forked from D-Net/dnet-hadoop
90 lines
2.8 KiB
Java
90 lines
2.8 KiB
Java
package eu.dnetlib.dhp.common.utils;
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import java.io.File;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.security.InvalidParameterException;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.Properties;
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import eu.dnetlib.dhp.common.java.PortBindings;
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import eu.dnetlib.dhp.common.java.Ports;
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import eu.dnetlib.dhp.common.java.Process;
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import eu.dnetlib.dhp.common.java.io.CloseableIterator;
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import eu.dnetlib.dhp.common.java.io.DataStore;
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import eu.dnetlib.dhp.common.java.io.FileSystemPath;
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import eu.dnetlib.dhp.common.java.porttype.AnyPortType;
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import eu.dnetlib.dhp.common.java.porttype.PortType;
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import org.apache.hadoop.conf.Configuration;
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import org.apache.hadoop.fs.FileSystem;
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import org.apache.hadoop.fs.Path;
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import static eu.dnetlib.dhp.common.WorkflowRuntimeParameters.OOZIE_ACTION_OUTPUT_FILENAME;
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/**
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* Simple process verifying whether given datastore is empty.
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* @author mhorst
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*
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*/
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public class EmptyDatastoreVerifierProcess implements Process {
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public static final String INPUT_PORT_NAME = "input";
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public static final String DEFAULT_ENCODING = "UTF-8";
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public static final String OUTPUT_PROPERTY_IS_EMPTY = "isEmpty";
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/**
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* Ports handled by this module.
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*/
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private final Ports ports;
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// ------------------------ CONSTRUCTORS --------------------------
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public EmptyDatastoreVerifierProcess() {
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// preparing ports
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Map<String, PortType> input = new HashMap<String, PortType>();
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input.put(INPUT_PORT_NAME, new AnyPortType());
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Map<String, PortType> output = Collections.emptyMap();
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ports = new Ports(input, output);
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}
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@Override
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public Map<String, PortType> getInputPorts() {
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return ports.getInput();
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}
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@Override
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public Map<String, PortType> getOutputPorts() {
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return ports.getOutput();
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}
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@Override
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public void run(PortBindings portBindings, Configuration conf, Map<String, String> parameters) throws Exception {
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if (!portBindings.getInput().containsKey(INPUT_PORT_NAME)) {
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throw new InvalidParameterException("missing input port!");
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}
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try (CloseableIterator<?> closeableIt = getIterator(conf, portBindings.getInput().get(INPUT_PORT_NAME))) {
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File file = new File(System.getProperty(OOZIE_ACTION_OUTPUT_FILENAME));
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Properties props = new Properties();
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props.setProperty(OUTPUT_PROPERTY_IS_EMPTY, Boolean.toString(!closeableIt.hasNext()));
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try (OutputStream os = new FileOutputStream(file)) {
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props.store(os, "");
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}
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}
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}
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/**
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* Returns iterator over datastore.
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*/
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protected CloseableIterator<?> getIterator(Configuration conf, Path path) throws IOException {
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return DataStore.getReader(new FileSystemPath(FileSystem.get(conf), path));
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}
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}
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