/*
* #!
* Ontopia Webed
* #-
* Copyright (C) 2001 - 2013 The Ontopia Project
* #-
* 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 net.ontopia.topicmaps.webed.impl.utils;
/**
* INTERNAL: Systematically generates strings that are guaranteed not to be
* repeated.
*/
public class UniqueStringCreator {
long basicCounter;
UniqueStringCreator parent;
public UniqueStringCreator() {
basicCounter = 0;
parent = null;
}
/**
* Each time this method is called, it will return a String that was not
* returned on any previous call, and thus will not be returned by any
* subsequent call.
*/
public String getNextUniqueString() {
String retVal = getNextUniqueStringRecursively();
increment();
return retVal;
}
private String getNextUniqueStringRecursively() {
String retVal = "";
if (parent != null) {
retVal += parent.getNextUniqueStringRecursively() + ".";
}
retVal += basicCounter;
return retVal;
}
private void increment() {
if (basicCounter == Long.MAX_VALUE) {
basicCounter = 0;
if (parent == null)
parent = new UniqueStringCreator();
else
parent.increment();
} else
basicCounter++;
}
private static void evaluate() {
UniqueStringCreator tested = new UniqueStringCreator();
for (int j = 0; j < 6; j++) {
for (int i = 0; i < 6; i++)
System.out.println(tested.getNextUniqueString());
System.out.println();
tested.basicCounter = Long.MAX_VALUE - 1;
}
tested.parent.basicCounter = Long.MAX_VALUE;
for (int i = 0; i < 6; i++)
System.out.println(tested.getNextUniqueString());
System.out.println();
tested.basicCounter = Long.MAX_VALUE;
for (int i = 0; i < 6; i++)
System.out.println(tested.getNextUniqueString());
System.out.println();
}
}