Updated C_Expression

git-svn-id: https://svn.d4science.research-infrastructures.eu/gcube/trunk/portlets/user/tabular-data-expression-widget@113951 82a268e6-3cf1-43bd-a215-b396298e98cf

.gwt/.gwt-log

@@ -126,3 +126,35 @@ Compiling...
    Compilation completed in 0.00 seconds
 Removing invalidated units
 Finding entry point classes
+Public resources found in...
+Translatable source found in...
+Found 0 cached/archived units.  Used 0 / 2737 units from cache.
+Compiling...
+   30% complete (ETR: 8 seconds)
+   30% complete (ETR: 8 seconds)
+   30% complete (ETR: 8 seconds)
+   30% complete (ETR: 8 seconds)
+   40% complete (ETR: 8 seconds)
+   50% complete (ETR: 6 seconds)
+   60% complete (ETR: 4 seconds)
+   70% complete (ETR: 3 seconds)
+   80% complete (ETR: 2 seconds)
+   90% complete (ETR: 1 seconds)
+   100% complete (ETR: 0 seconds)
+   Compilation completed in 32.50 seconds
+Removing invalidated units
+Finding entry point classes
+Public resources found in...
+Translatable source found in...
+Found 2737 cached/archived units.  Used 2737 / 2737 units from cache.
+Compiling...
+   Compilation completed in 0.00 seconds
+Removing invalidated units
+Finding entry point classes
+Public resources found in...
+Translatable source found in...
+Found 2737 cached/archived units.  Used 2737 / 2737 units from cache.
+Compiling...
+   Compilation completed in 0.00 seconds
+Removing invalidated units
+Finding entry point classes

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/expression/C_MultivaluedExpression.java

@@ -4,4 +4,7 @@ public interface C_MultivaluedExpression {
 	
 	public String getIdMulti();
 	
+	public String getReadableMultivaluedString();
+	
+
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/C_ExternalReferenceExpression.java

@@ -21,9 +21,11 @@ public class C_ExternalReferenceExpression extends C_Expression implements
 			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "ExternalReferenceExpression("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "ExternalReferenceExpression("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	@Override
@@ -52,6 +54,13 @@ public class C_ExternalReferenceExpression extends C_Expression implements
 		this.rightArgument = rightArgument;
 	}
 	
+
+	@Override
+	public String getReadableMultivaluedString() {
+		return readableExpression;
+	}
+
+	
 	@Override
 	public String toString() {
 		return "ExternalReferenceExpression [ id=" + id + ", leftArgument="

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_AggregationExpression.java

@@ -22,9 +22,10 @@ public class C_AggregationExpression extends C_Expression {
 
 	public C_AggregationExpression(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "AggregationExpression("
-				+ argument.getReadableExpression() + ")";
-		
+		if (argument != null) {
+			this.readableExpression = "AggregationExpression("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	@Override
@@ -36,7 +37,6 @@ public class C_AggregationExpression extends C_Expression {
 		return "DataType";
 	}
 
-	
 	public C_Expression getArgument() {
 		return argument;
 	}

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_Avg.java

@@ -24,8 +24,10 @@ public class C_Avg extends C_AggregationExpression {
 	 */
 	public C_Avg(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "AVG("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "AVG(" + argument.getReadableExpression()
+					+ ")";
+		}
 
 	}
 

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_Count.java

@@ -5,8 +5,8 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
 public class C_Count extends C_AggregationExpression {
@@ -24,8 +24,10 @@ public class C_Count extends C_AggregationExpression {
 	 */
 	public C_Count(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "Count("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "Count("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -42,13 +44,9 @@ public class C_Count extends C_AggregationExpression {
 		return id;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Count [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_Max.java

@@ -24,8 +24,10 @@ public class C_Max extends C_AggregationExpression {
 	 */
 	public C_Max(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "Max("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "Max(" + argument.getReadableExpression()
+					+ ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_Min.java

@@ -24,21 +24,21 @@ public class C_Min extends C_AggregationExpression {
 	 */
 	public C_Min(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "Min("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "Min(" + argument.getReadableExpression()
+					+ ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.MIN;
 	}
 
-
 	@Override
 	public String getId() {
 		return id;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Min [id=" + id + ", argument=" + argument + "]";

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_ST_Extent.java

@@ -23,8 +23,10 @@ public class C_ST_Extent extends C_AggregationExpression {
 	 */
 	public C_ST_Extent(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "ST_Extent("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "ST_Extent("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/aggregation/C_Sum.java

@@ -24,8 +24,10 @@ public class C_Sum extends C_AggregationExpression {
 	 */
 	public C_Sum(C_Expression argument) {
 		this.argument = argument;
-		this.readableExpression = "Sum("
-				+ argument.getReadableExpression() + ")";
+		if (argument != null) {
+			this.readableExpression = "Sum(" + argument.getReadableExpression()
+					+ ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Addition.java

@@ -5,16 +5,15 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
-public class C_Addition  extends C_ArithmeticExpression {
+public class C_Addition extends C_ArithmeticExpression {
 
 	private static final long serialVersionUID = 3148009575987859751L;
 
-	private String id="Addition";
-	
+	private String id = "Addition";
 
 	public C_Addition() {
 
@@ -23,16 +22,17 @@ public class C_Addition  extends C_ArithmeticExpression {
 	public C_Addition(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Addition("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Addition("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.ADDITION;
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
@@ -40,8 +40,8 @@ public class C_Addition  extends C_ArithmeticExpression {
 
 	@Override
 	public String toString() {
-		return "Addition [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Addition [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_ArithmeticExpression.java

@@ -30,16 +30,19 @@ public class C_ArithmeticExpression extends C_Expression {
 			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "ArithmeticExpression("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "ArithmeticExpression("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	static {
 		acceptedDataTypes.add(ColumnDataType.Numeric);
 		acceptedDataTypes.add(ColumnDataType.Integer);
-		//acceptedDataTypes.add(ColumnDataType.Date); //Date+Date?
-		//acceptedDataTypes.add(ColumnDataType.Geometry); //Point+Point PostiGIS?
+		// acceptedDataTypes.add(ColumnDataType.Date); //Date+Date?
+		// acceptedDataTypes.add(ColumnDataType.Geometry); //Point+Point
+		// PostiGIS?
 	}
 
 	public String getReturnedDataType() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Division.java

@@ -5,15 +5,14 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
-public class C_Division  extends C_ArithmeticExpression {
+public class C_Division extends C_ArithmeticExpression {
 
 	private static final long serialVersionUID = 6678032753615890456L;
-	private String id="Division";
-	
+	private String id = "Division";
 
 	public C_Division() {
 
@@ -22,16 +21,17 @@ public class C_Division  extends C_ArithmeticExpression {
 	public C_Division(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Division("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Division("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.DIVISION;
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
@@ -39,8 +39,8 @@ public class C_Division  extends C_ArithmeticExpression {
 
 	@Override
 	public String toString() {
-		return "Division [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Division [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Exponentiation.java

@@ -14,8 +14,6 @@ public class C_Exponentiation extends C_ArithmeticExpression {
 	private static final long serialVersionUID = -8124478792466278925L;
 	private String id = "Exponentiation";
 
-	
-	
 	public C_Exponentiation() {
 
 	}
@@ -24,12 +22,15 @@ public class C_Exponentiation extends C_ArithmeticExpression {
 	 * 
 	 * @param argument
 	 */
-	public C_Exponentiation(C_Expression leftArgument, C_Expression rightArgument) {
+	public C_Exponentiation(C_Expression leftArgument,
+			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Exponentiation("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Exponentiation("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 
 	}
 
@@ -37,20 +38,15 @@ public class C_Exponentiation extends C_ArithmeticExpression {
 		return C_OperatorType.EXPONENTIATION;
 	}
 
-
 	@Override
 	public String getId() {
 		return id;
 	}
 
-	
-
 	@Override
 	public String toString() {
-		return "Exponentiation [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Exponentiation [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Modulus.java

@@ -5,15 +5,14 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
-public class C_Modulus  extends C_ArithmeticExpression {
+public class C_Modulus extends C_ArithmeticExpression {
 
 	private static final long serialVersionUID = -4068595785080246810L;
-	private String id="Modulus";
-	
+	private String id = "Modulus";
 
 	public C_Modulus() {
 
@@ -22,16 +21,17 @@ public class C_Modulus  extends C_ArithmeticExpression {
 	public C_Modulus(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Modulus("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Modulus("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.MODULUS;
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
@@ -39,8 +39,8 @@ public class C_Modulus  extends C_ArithmeticExpression {
 
 	@Override
 	public String toString() {
-		return "Modulus [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Modulus [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Multiplication.java

@@ -5,33 +5,34 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
-public class C_Multiplication  extends C_ArithmeticExpression {
+public class C_Multiplication extends C_ArithmeticExpression {
 
 	private static final long serialVersionUID = 4822682666900687606L;
-	private String id="Multiplication";
-	
+	private String id = "Multiplication";
 
 	public C_Multiplication() {
 
 	}
 
-	public C_Multiplication(C_Expression leftArgument, C_Expression rightArgument) {
+	public C_Multiplication(C_Expression leftArgument,
+			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Multiplication("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Multiplication("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.MULTIPLICATION;
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
@@ -39,8 +40,8 @@ public class C_Multiplication  extends C_ArithmeticExpression {
 
 	@Override
 	public String toString() {
-		return "Multiplication [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Multiplication [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/arithmetic/C_Subtraction.java

@@ -5,16 +5,15 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
 
 /**
  * 
- * @author giancarlo
- * email: <a href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a> 
+ * @author giancarlo email: <a
+ *         href="mailto:g.panichi@isti.cnr.it">g.panichi@isti.cnr.it</a>
  *
  */
-public class C_Subtraction  extends C_ArithmeticExpression {
+public class C_Subtraction extends C_ArithmeticExpression {
 
 	private static final long serialVersionUID = 3148009575987859751L;
 
-	private String id="Subtraction";
-	
+	private String id = "Subtraction";
 
 	public C_Subtraction() {
 
@@ -23,16 +22,17 @@ public class C_Subtraction  extends C_ArithmeticExpression {
 	public C_Subtraction(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Subtraction("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Subtraction("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
 		return C_OperatorType.SUBTRACTION;
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
@@ -40,8 +40,8 @@ public class C_Subtraction  extends C_ArithmeticExpression {
 
 	@Override
 	public String toString() {
-		return "Subtraction [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "Subtraction [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_Equals.java

@@ -10,7 +10,7 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
  * 
  */
 public class C_Equals extends C_Expression {
-	protected String id="Equals";
+	protected String id = "Equals";
 
 	private static final long serialVersionUID = 3154667914317692836L;
 	protected C_Expression leftArgument;
@@ -23,9 +23,11 @@ public class C_Equals extends C_Expression {
 	public C_Equals(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Equals("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Equals("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -36,13 +38,11 @@ public class C_Equals extends C_Expression {
 		return "Boolean";
 	}
 
-	
 	@Override
 	public String getId() {
 		return id;
 	}
 
-
 	public C_Expression getLeftArgument() {
 		return leftArgument;
 	}
@@ -65,6 +65,4 @@ public class C_Equals extends C_Expression {
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_GreaterOrEquals.java

@@ -16,7 +16,7 @@ public class C_GreaterOrEquals extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_GreaterOrEquals(){
+	public C_GreaterOrEquals() {
 
 	}
 
@@ -24,9 +24,11 @@ public class C_GreaterOrEquals extends C_Expression {
 			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "GreaterOrEquals("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "GreaterOrEquals("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_GreaterThan.java

@@ -15,16 +15,18 @@ public class C_GreaterThan extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_GreaterThan(){
+	public C_GreaterThan() {
 
 	}
 
 	public C_GreaterThan(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "GreaterThan("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "GreaterThan("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_LessOrEquals.java

@@ -15,16 +15,18 @@ public class C_LessOrEquals extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_LessOrEquals(){
+	public C_LessOrEquals() {
 
 	}
 
 	public C_LessOrEquals(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "LessOrEquals("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "LessOrEquals("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_LessThan.java

@@ -15,16 +15,19 @@ public class C_LessThan extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_LessThan(){
+	public C_LessThan() {
 
 	}
 
 	public C_LessThan(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "LessThan("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "LessThan("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
+
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_NotEquals.java

@@ -11,20 +11,22 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
  */
 public class C_NotEquals extends C_Expression {
 	private static final long serialVersionUID = 7587723477959909679L;
-	protected String id="NotEquals";
+	protected String id = "NotEquals";
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_NotEquals(){
+	public C_NotEquals() {
 
 	}
 
 	public C_NotEquals(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "NotEquals("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "NotEquals("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -40,7 +42,6 @@ public class C_NotEquals extends C_Expression {
 		return id;
 	}
 
-
 	public C_Expression getLeftArgument() {
 		return leftArgument;
 	}
@@ -63,5 +64,4 @@ public class C_NotEquals extends C_Expression {
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_NotGreater.java

@@ -11,20 +11,22 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.expression.C_Expressi
  */
 public class C_NotGreater extends C_Expression {
 	private static final long serialVersionUID = 6783019184437499833L;
-	protected String id="NotGreater";
+	protected String id = "NotGreater";
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_NotGreater(){
+	public C_NotGreater() {
 
 	}
 
 	public C_NotGreater(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "NotGreater("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "NotGreater("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -35,14 +37,11 @@ public class C_NotGreater extends C_Expression {
 		return "Boolean";
 	}
 
-	
-	
 	@Override
 	public String getId() {
 		return id;
 	}
 
-
 	public C_Expression getLeftArgument() {
 		return leftArgument;
 	}
@@ -65,6 +64,4 @@ public class C_NotGreater extends C_Expression {
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/comparable/C_NotLess.java

@@ -15,16 +15,18 @@ public class C_NotLess extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_NotLess(){
+	public C_NotLess() {
 
 	}
 
 	public C_NotLess(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "NotLess("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "NotLess("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/functions/C_Cast.java

@@ -17,19 +17,19 @@ public class C_Cast extends C_Expression {
 	protected C_Expression leftArgument;
 	protected ColumnDataType rightArgument;
 
-	public C_Cast(){
+	public C_Cast() {
 		super();
 	}
 
-	
-	public C_Cast(C_Expression leftArgument,
-			ColumnDataType rightArgument) {
+	public C_Cast(C_Expression leftArgument, ColumnDataType rightArgument) {
 		super();
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Cast("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getColumnDataTypeLabel() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Cast("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getColumnDataTypeLabel() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -61,23 +61,25 @@ public class C_Cast extends C_Expression {
 		this.rightArgument = rightArgument;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Cast [id=" + id + ", leftArgument=" + leftArgument
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-	
-	public boolean isCastSupported(ColumnDataType sourceType,ColumnDataType targetType){
+	public boolean isCastSupported(ColumnDataType sourceType,
+			ColumnDataType targetType) {
 		// from / to text
-		if(targetType==ColumnDataType.Text||sourceType==ColumnDataType.Text) return true;
+		if (targetType == ColumnDataType.Text
+				|| sourceType == ColumnDataType.Text)
+			return true;
 		// same class
-		if(sourceType==targetType) return true;
+		if (sourceType == targetType)
+			return true;
 		// integer <--> numeric
-		if((sourceType==ColumnDataType.Integer && targetType==ColumnDataType.Numeric)
-				|| (sourceType==ColumnDataType.Numeric && targetType==ColumnDataType.Integer))return true;
+		if ((sourceType == ColumnDataType.Integer && targetType == ColumnDataType.Numeric)
+				|| (sourceType == ColumnDataType.Numeric && targetType == ColumnDataType.Integer))
+			return true;
 		return false;
 	}
 

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Concat.java

@@ -16,19 +16,19 @@ public class C_Concat extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_Concat(){
+	public C_Concat() {
 		super();
 	}
 
-	
-	public C_Concat(C_Expression leftArgument,
-			C_Expression rightArgument) {
+	public C_Concat(C_Expression leftArgument, C_Expression rightArgument) {
 		super();
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Concat("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Concat("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -60,13 +60,10 @@ public class C_Concat extends C_Expression {
 		this.rightArgument = rightArgument;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Concat [id=" + id + ", leftArgument=" + leftArgument
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Lenght.java

@@ -14,17 +14,18 @@ public class C_Lenght extends C_Expression {
 	protected String id = "Length";
 	protected C_Expression argument;
 
-	public C_Lenght(){
+	public C_Lenght() {
 
 	}
 
 	public C_Lenght(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "Lenght("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Lenght("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.LENGTH;
 	}

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Levenshtein.java

@@ -16,18 +16,18 @@ public class C_Levenshtein extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_Levenshtein(){
+	public C_Levenshtein() {
 
 	}
 
-	
-	public C_Levenshtein(C_Expression leftArgument,
-			C_Expression rightArgument) {
+	public C_Levenshtein(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Levenshtein("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Levenshtein("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -59,14 +59,10 @@ public class C_Levenshtein extends C_Expression {
 		this.rightArgument = rightArgument;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Levenshtein [id=" + id + ", leftArgument=" + leftArgument
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-	
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Lower.java

@@ -14,17 +14,18 @@ public class C_Lower extends C_Expression {
 	protected String id = "Lower";
 	protected C_Expression argument;
 
-	public C_Lower(){
+	public C_Lower() {
 
 	}
 
 	public C_Lower(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "Lower("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Lower("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.LOWER;
 	}
@@ -51,8 +52,4 @@ public class C_Lower extends C_Expression {
 		return "Lower [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-	
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_MD5.java

@@ -14,17 +14,18 @@ public class C_MD5 extends C_Expression {
 	protected String id = "MD5";
 	protected C_Expression argument;
 
-	public C_MD5(){
+	public C_MD5() {
 
 	}
 
 	public C_MD5(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "MD5("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "MD5(" + argument.getReadableExpression()
+					+ ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.MD5;
 	}
@@ -51,8 +52,4 @@ public class C_MD5 extends C_Expression {
 		return "MD5 [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-	
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Similarity.java

@@ -16,18 +16,18 @@ public class C_Similarity extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_Similarity(){
+	public C_Similarity() {
 
 	}
 
-	
-	public C_Similarity(C_Expression leftArgument,
-			C_Expression rightArgument) {
+	public C_Similarity(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "Similarity("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Similarity("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {
@@ -59,14 +59,10 @@ public class C_Similarity extends C_Expression {
 		this.rightArgument = rightArgument;
 	}
 
-
 	@Override
 	public String toString() {
 		return "Similarity [id=" + id + ", leftArgument=" + leftArgument
 				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-	
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Soundex.java

@@ -14,17 +14,18 @@ public class C_Soundex extends C_Expression {
 	protected String id = "Soundex";
 	protected C_Expression argument;
 
-	public C_Soundex(){
+	public C_Soundex() {
 
 	}
 
 	public C_Soundex(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "Soundex("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Soundex("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.SOUNDEX;
 	}
@@ -51,8 +52,4 @@ public class C_Soundex extends C_Expression {
 		return "Soundex [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-	
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_SubstringByIndex.java

@@ -18,22 +18,22 @@ public class C_SubstringByIndex extends C_Expression {
 	private C_Expression fromIndex;
 	private C_Expression toIndex;
 
-	public C_SubstringByIndex(){
+	public C_SubstringByIndex() {
 		super();
 	}
 
-	
-	public  C_SubstringByIndex(C_Expression sourceString, C_Expression fromIndex, C_Expression toIndex) {
+	public C_SubstringByIndex(C_Expression sourceString,
+			C_Expression fromIndex, C_Expression toIndex) {
 		super();
 		this.sourceString = sourceString;
-		this.fromIndex=fromIndex;
-		this.toIndex=toIndex;
-		this.readableExpression = "SubstringByIndex("
-				+ sourceString.getReadableExpression() + ","
-				+ fromIndex.getReadableExpression() + ","
-				+ toIndex.getReadableExpression() + ")";
-		
-		
+		this.fromIndex = fromIndex;
+		this.toIndex = toIndex;
+		if (sourceString != null && fromIndex != null && toIndex != null) {
+			this.readableExpression = "SubstringByIndex("
+					+ sourceString.getReadableExpression() + ","
+					+ fromIndex.getReadableExpression() + ","
+					+ toIndex.getReadableExpression() + ")";
+		}
 
 	}
 
@@ -50,46 +50,34 @@ public class C_SubstringByIndex extends C_Expression {
 		return id;
 	}
 
-
 	public C_Expression getSourceString() {
 		return sourceString;
 	}
 
-
 	public void setSourceString(C_Expression sourceString) {
 		this.sourceString = sourceString;
 	}
 
-
 	public C_Expression getFromIndex() {
 		return fromIndex;
 	}
 
-
 	public void setFromIndex(C_Expression fromIndex) {
 		this.fromIndex = fromIndex;
 	}
 
-
 	public C_Expression getToIndex() {
 		return toIndex;
 	}
 
-
 	public void setToIndex(C_Expression toIndex) {
 		this.toIndex = toIndex;
 	}
 
-
 	@Override
 	public String toString() {
-		return "SubstringByIndex [id=" + id + ", sourceString="
-				+ sourceString + ", fromIndex=" + fromIndex + ", toIndex="
-				+ toIndex + "]";
+		return "SubstringByIndex [id=" + id + ", sourceString=" + sourceString
+				+ ", fromIndex=" + fromIndex + ", toIndex=" + toIndex + "]";
 	}
 
-	
-
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_SubstringByRegex.java

@@ -21,14 +21,15 @@ public class C_SubstringByRegex extends C_Expression {
 		super();
 	}
 
-	public C_SubstringByRegex(C_Expression sourceString,
-			C_Expression regex) {
+	public C_SubstringByRegex(C_Expression sourceString, C_Expression regex) {
 		super();
 		this.sourceString = sourceString;
 		this.regex = regex;
-		this.readableExpression = "SubstringByRegex("
-				+ sourceString.getReadableExpression() + ","
-				+ regex.getReadableExpression() + ")";
+		if (sourceString != null && regex != null) {
+			this.readableExpression = "SubstringByRegex("
+					+ sourceString.getReadableExpression() + ","
+					+ regex.getReadableExpression() + ")";
+		}
 
 	}
 
@@ -63,8 +64,8 @@ public class C_SubstringByRegex extends C_Expression {
 
 	@Override
 	public String toString() {
-		return "SubstringByRegex [id=" + id + ", sourceString="
-				+ sourceString + ", regex=" + regex + "]";
+		return "SubstringByRegex [id=" + id + ", sourceString=" + sourceString
+				+ ", regex=" + regex + "]";
 	}
 
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_SubstringPosition.java

@@ -21,19 +21,18 @@ public class C_SubstringPosition extends C_Expression {
 		super();
 	}
 
-
 	public C_SubstringPosition(C_Expression leftArgument,
 			C_Expression rightArgument) {
 		super();
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "SubstringPosition("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "SubstringPosition("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
-
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.SUBSTRING_BY_REGEX;
 	}
@@ -47,33 +46,26 @@ public class C_SubstringPosition extends C_Expression {
 		return id;
 	}
 
-
 	public C_Expression getLeftArgument() {
 		return leftArgument;
 	}
 
-
 	public void setLeftArgument(C_Expression leftArgument) {
 		this.leftArgument = leftArgument;
 	}
 
-
 	public C_Expression getRightArgument() {
 		return rightArgument;
 	}
 
-
 	public void setRightArgument(C_Expression rightArgument) {
 		this.rightArgument = rightArgument;
 	}
 
-
 	@Override
 	public String toString() {
-		return "SubstringPosition [id=" + id + ", leftArgument="
-				+ leftArgument + ", rightArgument=" + rightArgument + "]";
+		return "SubstringPosition [id=" + id + ", leftArgument=" + leftArgument
+				+ ", rightArgument=" + rightArgument + "]";
 	}
 
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_TextBeginsWith.java

@@ -16,18 +16,19 @@ public class C_TextBeginsWith extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_TextBeginsWith(){
+	public C_TextBeginsWith() {
 
 	}
 
-	
 	public C_TextBeginsWith(C_Expression leftArgument,
 			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "TextBeginsWith("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "TextBeginsWith("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_TextContains.java

@@ -15,16 +15,18 @@ public class C_TextContains extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_TextContains(){
+	public C_TextContains() {
 
 	}
 
 	public C_TextContains(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "TextContains("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "TextContains("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_TextEndsWith.java

@@ -15,16 +15,18 @@ public class C_TextEndsWith extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_TextEndsWith(){
+	public C_TextEndsWith() {
 
 	}
 
 	public C_TextEndsWith(C_Expression leftArgument, C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "TextEndsWith("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "TextEndsWith("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_TextMatchSQLRegexp.java

@@ -15,7 +15,7 @@ public class C_TextMatchSQLRegexp extends C_Expression {
 	protected C_Expression leftArgument;
 	protected C_Expression rightArgument;
 
-	public C_TextMatchSQLRegexp(){
+	public C_TextMatchSQLRegexp() {
 
 	}
 
@@ -23,9 +23,11 @@ public class C_TextMatchSQLRegexp extends C_Expression {
 			C_Expression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
-		this.readableExpression = "TextMatchSQLRegexp("
-				+ leftArgument.getReadableExpression() + ","
-				+ rightArgument.getReadableExpression() + ")";
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "TextMatchSQLRegexp("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_TextReplaceMatchingRegex.java

@@ -30,10 +30,12 @@ public class C_TextReplaceMatchingRegex extends C_Expression {
 		this.toCheckText = toCheckText;
 		this.regexp = regexp;
 		this.replacing = replacing;
-		this.readableExpression = "TextReplaceMatchingRegex("
-				+ toCheckText.getReadableExpression() + ","
-				+ regexp.getReadableExpression() + ","
-				+ replacing.getReadableExpression() + ")";
+		if (toCheckText != null && regexp != null && replacing != null) {
+			this.readableExpression = "TextReplaceMatchingRegex("
+					+ toCheckText.getReadableExpression() + ","
+					+ regexp.getReadableExpression() + ","
+					+ replacing.getReadableExpression() + ")";
+		}
 
 	}
 

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Trim.java

@@ -14,17 +14,18 @@ public class C_Trim extends C_Expression {
 	protected String id = "Trim";
 	protected C_Expression argument;
 
-	public C_Trim(){
+	public C_Trim() {
 
 	}
 
 	public C_Trim(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "Trim("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Trim("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.TRIM;
 	}
@@ -51,7 +52,4 @@ public class C_Trim extends C_Expression {
 		return "Trim [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/composite/text/C_Upper.java

@@ -14,17 +14,18 @@ public class C_Upper extends C_Expression {
 	protected String id = "Upper";
 	protected C_Expression argument;
 
-	public C_Upper(){
+	public C_Upper() {
 
 	}
 
 	public C_Upper(C_Expression argument) {
-		this.argument=argument;
-		this.readableExpression = "Upper("
-				+ argument.getReadableExpression() + ")";
+		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Upper("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
-
 	public C_OperatorType getOperator() {
 		return C_OperatorType.UPPER;
 	}
@@ -51,8 +52,4 @@ public class C_Upper extends C_Expression {
 		return "Upper [id=" + id + ", argument=" + argument + "]";
 	}
 
-	
-	
-	
-
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/C_ColumnReference.java

@@ -29,8 +29,10 @@ public class C_ColumnReference extends C_Leaf {
 				tableId = trId.getTableId();
 			}
 		}
-		this.readableExpression = "ColumnReference(" + tableId + ","
-				+ dataType.getColumnDataTypeLabel() + "," + columnId + ")";
+		if (tableId != null && columnId != null && dataType != null) {
+			this.readableExpression = "ColumnReference(" + tableId + ","
+					+ dataType.getColumnDataTypeLabel() + "," + columnId + ")";
+		}
 
 	}
 

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/C_ColumnReferencePlaceholder.java

@@ -9,13 +9,18 @@ public class C_ColumnReferencePlaceholder extends C_Leaf {
 	protected String columnId;
 	protected ColumnDataType dataType;
 
-	public C_ColumnReferencePlaceholder(){
+	public C_ColumnReferencePlaceholder() {
 
 	}
 
 	public C_ColumnReferencePlaceholder(ColumnDataType dataType, String columnId) {
 		this.dataType = dataType;
 		this.columnId = columnId;
+		if (dataType != null && columnId != null) {
+			this.readableExpression = "PlaceHolder("
+					+ dataType.getColumnDataTypeLabel() +
+					"," + columnId + ")";
+		}
 
 	}
 

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/C_ConstantList.java

@@ -14,6 +14,18 @@ public class C_ConstantList extends C_Leaf implements C_MultivaluedExpression {
 	
 	public C_ConstantList(List<TD_Value> arguments) {
 		this.arguments = arguments;
+		String cList=new String();
+		for(TD_Value tdValue:arguments){
+			if(tdValue!=null){
+				if(cList.isEmpty()){
+					cList=cList.concat(tdValue.getReadableExpression());
+				} else {
+					cList=cList.concat(",").concat(tdValue.getReadableExpression());
+				}	
+
+			}
+		}
+		this.readableExpression = "CostantList("+cList+")";
 	}
 	
 	@Override
@@ -35,6 +47,11 @@ public class C_ConstantList extends C_Leaf implements C_MultivaluedExpression {
 		this.arguments = arguments;
 	}
 
+	@Override
+	public String getReadableMultivaluedString() {
+		return readableExpression;
+	}
+	
 	@Override
 	public String toString() {
 		return "ConstantList [id=" + id + ", arguments=" + arguments + "]";
@@ -44,4 +61,6 @@ public class C_ConstantList extends C_Leaf implements C_MultivaluedExpression {
 
 	
 	
+	
+
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/C_Leaf.java

@@ -10,7 +10,7 @@ public class C_Leaf extends C_Expression {
 	protected String id="Leaf";
 	
 	public C_Leaf(){
-		
+		this.readableExpression = "Leaf()";
 	}
 	
 	@Override

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/C_Range.java

@@ -10,13 +10,18 @@ public class C_Range extends C_Leaf implements C_MultivaluedExpression {
 	protected TD_Value minimum;
 	protected TD_Value maximum;
 
-	public C_Range(){
+	public C_Range() {
 
 	}
 
 	public C_Range(TD_Value minimum, TD_Value maximum) {
 		this.minimum = minimum;
 		this.maximum = maximum;
+		if (minimum != null && maximum != null) {
+			this.readableExpression = "Range("
+					+ minimum.getReadableExpression() + ","
+					+ maximum.getReadableExpression() + ")";
+		}
 	}
 
 	@Override
@@ -29,7 +34,6 @@ public class C_Range extends C_Leaf implements C_MultivaluedExpression {
 		return id;
 	}
 
-
 	public TD_Value getMinimum() {
 		return minimum;
 	}
@@ -46,6 +50,11 @@ public class C_Range extends C_Leaf implements C_MultivaluedExpression {
 		this.maximum = maximum;
 	}
 
+	@Override
+	public String getReadableMultivaluedString() {
+		return readableExpression;
+	}
+	
 	@Override
 	public String toString() {
 		return "Range [id=" + id + ", minimum=" + minimum + ", maximum="

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/leaf/TD_Value.java

@@ -5,17 +5,22 @@ import org.gcube.portlets.user.td.widgetcommonevent.shared.tr.column.ColumnDataT
 public class TD_Value extends C_Leaf {
 
 	private static final long serialVersionUID = 2802022467528178596L;
-	protected String id="TD_Value";
+	protected String id = "TD_Value";
 	protected String value;
 	protected ColumnDataType valueType;
 
-	public TD_Value(){
+	public TD_Value() {
 
 	}
 
-	public TD_Value(ColumnDataType valueType, String value){
-		this.valueType=valueType;
-		this.value=value;
+	public TD_Value(ColumnDataType valueType, String value) {
+		this.valueType = valueType;
+		this.value = value;
+		if (valueType != null) {
+			this.readableExpression = "TDValue("
+					+ valueType.getColumnDataTypeLabel() + "," + value + ")";
+		}
+
 	}
 
 	@Override
@@ -44,6 +49,4 @@ public class TD_Value extends C_Leaf {
 		return "TD_Value [value=" + value + ", valueType=" + valueType + "]";
 	}
 
-	
-	
 }

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_And.java

@@ -23,10 +23,35 @@ public class C_And extends C_Expression {
 	
 	public C_And(C_Expression... arguments) {
 		this.arguments = Arrays.asList(arguments);
+		String cList=new String();
+		for(C_Expression arg:arguments){
+			if(arg!=null){
+				if(cList.isEmpty()){
+					cList=cList.concat(arg.getReadableExpression());
+				} else {
+					cList=cList.concat(",").concat(arg.getReadableExpression());
+				}	
+
+			}
+		}
+		this.readableExpression = "And("+cList+")";
+		
 	}
 
 	public C_And(List<C_Expression> arguments) {
 		this.arguments = arguments;
+		String cList=new String();
+		for(C_Expression arg:arguments){
+			if(arg!=null){
+				if(cList.isEmpty()){
+					cList=cList.concat(arg.getReadableExpression());
+				} else {
+					cList=cList.concat(",").concat(arg.getReadableExpression());
+				}	
+
+			}
+		}
+		this.readableExpression = "And("+cList+")";
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_Between.java

@@ -24,6 +24,11 @@ public class C_Between extends C_Expression {
 	public C_Between(C_Expression leftArgument, C_Range rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "Between("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableExpression() + ")";
+		}
 	}
 
 	

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_IsNotNull.java

@@ -21,6 +21,10 @@ public class C_IsNotNull extends C_Expression {
 	
 	public C_IsNotNull(C_Expression argument) {
 		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "IsNotNull("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_IsNull.java

@@ -21,6 +21,10 @@ public class C_IsNull extends C_Expression {
 	
 	public C_IsNull(C_Expression argument) {
 		this.argument=argument;
+		if (argument != null) {
+			this.readableExpression = "IsNull("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_Not.java

@@ -20,6 +20,10 @@ public class C_Not extends C_Expression {
 	
 	public C_Not(C_Expression argument) {
 		this.argument = argument;
+		if (argument != null) {
+			this.readableExpression = "Not("
+					+ argument.getReadableExpression() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_Or.java

@@ -23,10 +23,35 @@ public class C_Or extends C_Expression {
 	
 	public C_Or(C_Expression... arguments) {
 		this.arguments = Arrays.asList(arguments);
+		String cList=new String();
+		for(C_Expression arg:arguments){
+			if(arg!=null){
+				if(cList.isEmpty()){
+					cList=cList.concat(arg.getReadableExpression());
+				} else {
+					cList=cList.concat(",").concat(arg.getReadableExpression());
+				}	
+
+			}
+		}
+		this.readableExpression = "Or("+cList+")";
+		
 	}
 
 	public C_Or(List<C_Expression> arguments) {
 		this.arguments = arguments;
+		String cList=new String();
+		for(C_Expression arg:arguments){
+			if(arg!=null){
+				if(cList.isEmpty()){
+					cList=cList.concat(arg.getReadableExpression());
+				} else {
+					cList=cList.concat(",").concat(arg.getReadableExpression());
+				}	
+
+			}
+		}
+		this.readableExpression = "Or("+cList+")";
 	}
 
 	public C_OperatorType getOperator() {

src/main/java/org/gcube/portlets/user/td/expressionwidget/shared/model/logical/C_ValueIsIn.java

@@ -24,6 +24,11 @@ public class C_ValueIsIn extends C_Expression {
 	public C_ValueIsIn(C_Expression leftArgument, C_MultivaluedExpression rightArgument) {
 		this.leftArgument = leftArgument;
 		this.rightArgument = rightArgument;
+		if (leftArgument != null && rightArgument != null) {
+			this.readableExpression = "ValueIsIn("
+					+ leftArgument.getReadableExpression() + ","
+					+ rightArgument.getReadableMultivaluedString() + ")";
+		}
 	}
 
 	public C_OperatorType getOperator() {