workspace-uploader/src/main/java/org/gcube/portlets/widgets/workspaceuploader/client/uploader/GenerateUUID.java

72 lines
1.9 KiB
Java

/**
*
*/
package org.gcube.portlets.widgets.workspaceuploader.client.uploader;
/**
*
* @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it Aug 6, 2015
*/
public class GenerateUUID {
private static final char[] CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();
/**
* Generate a random uuid of the specified length. Example: uuid(15) returns
* "VcydxgltxrVZSTV"
*
* @param len
* the desired number of characters
*/
public static String get(int len) {
return get(len, CHARS.length);
}
/**
* Generate a random uuid of the specified length, and radix. Examples:
* <ul>
* <li>uuid(8, 2) returns "01001010" (8 character ID, base=2)
* <li>uuid(8, 10) returns "47473046" (8 character ID, base=10)
* <li>uuid(8, 16) returns "098F4D35" (8 character ID, base=16)
* </ul>
*
* @param len
* the desired number of characters
* @param radix
* the number of allowable values for each character (must be <=
* 62)
*/
public static String get(int len, int radix) {
if (radix > CHARS.length) {
throw new IllegalArgumentException();
}
char[] uuid = new char[len];
// Compact form
for (int i = 0; i < len; i++) {
uuid[i] = CHARS[(int) (Math.random() * radix)];
}
return new String(uuid);
}
/**
* Generate a RFC4122, version 4 ID. Example:
* "92329D39-6F5C-4520-ABFC-AAB64544E172"
*/
public static String get() {
char[] uuid = new char[36];
int r;
// rfc4122 requires these characters
uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
uuid[14] = '4';
// Fill in random data. At i==19 set the high bits of clock sequence as
// per rfc4122, sec. 4.1.5
for (int i = 0; i < 36; i++) {
if (uuid[i] == 0) {
r = (int) (Math.random() * 16);
uuid[i] = CHARS[(i == 19) ? (r & 0x3) | 0x8 : r & 0xf];
}
}
return new String(uuid);
}
}