001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.fusesource.hawtdb.api;
018    
019    
020    /**
021     * StringPrefixer is a {@link Prefixer} implementation that works on strings.
022     * 
023     * @author <a href="http://hiramchirino.com">Hiram Chirino</a>
024     */
025    public class StringPrefixer implements Prefixer<String> {
026    
027        /**
028         * Example: If value1 is "Hello World" and value 2 is "Help Me" then the
029         * result will be: "Help"
030         * 
031         * @see Prefixer#getSimplePrefix
032         */
033        public String getSimplePrefix(String value1, String value2) {
034            char[] c1 = value1.toCharArray();
035            char[] c2 = value2.toCharArray();
036            int n = Math.min(c1.length, c2.length);
037            int i = 0;
038            while (i < n) {
039                if (c1[i] != c2[i]) {
040                    return value2.substring(0, i + 1);
041                }
042                i++;
043            }
044    
045            if (n == c2.length) {
046                return value2;
047            }
048            return value2.substring(0, n);
049        }
050    }