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Common code used in all samples

There is a newer version: 0.9.6

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jboss.gwt.elemento.sample.common;

final class UUID {

    private UUID() {
    }

    private static final char[] CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

    /**
     * Generate a RFC4122, version 4 ID. Example:
     * "92329D39-6F5C-4520-ABFC-AAB64544E172"
     */
    static String uuid() {
        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);
    }
}