/*
* $Id: PrefixTrie.java 651946 2008-04-27 13:41:38Z apetrelli $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.struts2.util;
/**
* Quickly matches a prefix to an object.
*
*/
public class PrefixTrie {
// supports 7-bit chars.
private static final int SIZE = 128;
Node root = new Node();
public void put(String prefix, Object value) {
Node current = root;
for (int i = 0; i < prefix.length(); i++) {
char c = prefix.charAt(i);
if (c > SIZE)
throw new IllegalArgumentException("'" + c + "' is too big.");
if (current.next[c] == null)
current.next[c] = new Node();
current = current.next[c];
}
current.value = value;
}
public Object get(String key) {
Node current = root;
for (int i = 0; i < key.length(); i++) {
char c = key.charAt(i);
if (c > SIZE)
return null;
current = current.next[c];
if (current == null)
return null;
if (current.value != null)
return current.value;
}
return null;
}
static class Node {
Object value;
Node[] next = new Node[SIZE];
}
}
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