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'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* Copyright (C) 2004-2014 Volker Bergmann ([email protected]).
* All rights reserved.
*
* 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.databene.commons.converter;
import java.util.HashSet;
import java.util.Set;
import org.databene.commons.ConversionException;
/**
* Assures uniqueness for all processed Strings by appending unique numbers to recurring instances.
*
* Created: 24.06.2008 19:41:08
* @since 0.4.4
* @author Volker Bergmann
*/
public class UniqueStringConverter extends AbstractConverter {
private static final int MAX_TRIES = 10000;
private Set usedStrings;
public UniqueStringConverter() {
super(String.class, String.class);
usedStrings = new HashSet();
}
@Override
public synchronized String convert(String sourceValue) throws ConversionException {
String resultValue = sourceValue;
if (usedStrings.contains(sourceValue)) {
boolean ok = false;
for (int i = 0; !ok && i < MAX_TRIES; i++) {
resultValue = sourceValue + i;
if (!usedStrings.contains(resultValue)) {
ok = true;
}
}
if (!ok)
throw new UnsupportedOperationException("not more than " + MAX_TRIES + " identical Strings can be made unique");
}
usedStrings.add(resultValue);
return resultValue;
}
@Override
public boolean isParallelizable() {
return false;
}
@Override
public boolean isThreadSafe() {
return true;
}
}