org.xerial.util.PrefixTree Maven / Gradle / Ivy
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* Copyright 2009 Taro L. Saito
*
* 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
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*--------------------------------------------------------------------------*/
//--------------------------------------
// XerialJ
//
// PrefixTree.java
// Since: 2010/03/25 23:11:30
//
// $URL$
// $Author$
//--------------------------------------
package org.xerial.util;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
/**
* Tree with prefix-search capability
*
* @author leo
*
* @param
*/
public class PrefixTree {
private TreeMap holder = new TreeMap();
public void clear() {
holder.clear();
}
public void add(String key, T entry) {
holder.put(key, entry);
}
public T findBy(String prefix) {
if (prefix == null)
return null;
String nextKey = holder.ceilingKey(prefix);
if (nextKey == null)
return null;
SortedMap tail = holder.tailMap(nextKey);
for (String key : tail.keySet()) {
if (key.startsWith(prefix)) {
return tail.get(key);
}
}
return null;
}
public T get(String key) {
return holder.get(key);
}
public Set keySet() {
return holder.keySet();
}
}
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