001 // Copyright 2004, 2005 The Apache Software Foundation 002 // 003 // Licensed under the Apache License, Version 2.0 (the "License"); 004 // you may not use this file except in compliance with the License. 005 // You may obtain a copy of the License at 006 // 007 // http://www.apache.org/licenses/LICENSE-2.0 008 // 009 // Unless required by applicable law or agreed to in writing, software 010 // distributed under the License is distributed on an "AS IS" BASIS, 011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012 // See the License for the specific language governing permissions and 013 // limitations under the License. 014 015 package org.apache.tapestry.util; 016 017 /** 018 * Used to split a string into substrings based on a single character 019 * delimiter. A fast, simple version of 020 * {@link java.util.StringTokenizer}. 021 * 022 * @author Howard Lewis Ship 023 * 024 **/ 025 026 public class StringSplitter 027 { 028 private char delimiter; 029 030 public StringSplitter(char delimiter) 031 { 032 this.delimiter = delimiter; 033 } 034 035 public char getDelimiter() 036 { 037 return delimiter; 038 } 039 040 /** 041 * Splits a string on the delimter into an array of String 042 * tokens. The delimiters are not included in the tokens. Null 043 * tokens (caused by two consecutive delimiter) are reduced to an 044 * empty string. Leading delimiters are ignored. 045 * 046 **/ 047 048 public String[] splitToArray(String value) 049 { 050 char[] buffer; 051 int i; 052 String[] result; 053 int resultCount = 0; 054 int start; 055 int length; 056 String token; 057 String[] newResult; 058 boolean first = true; 059 060 buffer = value.toCharArray(); 061 062 result = new String[3]; 063 064 start = 0; 065 length = 0; 066 067 for (i = 0; i < buffer.length; i++) 068 { 069 if (buffer[i] != delimiter) 070 { 071 length++; 072 continue; 073 } 074 075 // This is used to ignore leading delimiter(s). 076 077 if (length > 0 || !first) 078 { 079 token = new String(buffer, start, length); 080 081 if (resultCount == result.length) 082 { 083 newResult = new String[result.length * 2]; 084 085 System.arraycopy(result, 0, newResult, 0, result.length); 086 087 result = newResult; 088 } 089 090 result[resultCount++] = token; 091 092 first = false; 093 } 094 095 start = i + 1; 096 length = 0; 097 } 098 099 // Special case: if the string contains no delimiters 100 // then it isn't really split. Wrap the input string 101 // in an array and return. This is a little optimization 102 // to prevent a new String instance from being 103 // created unnecessarily. 104 105 if (start == 0 && length == buffer.length) 106 { 107 result = new String[1]; 108 result[0] = value; 109 return result; 110 } 111 112 // If the string is all delimiters, then this 113 // will result in a single empty token. 114 115 token = new String(buffer, start, length); 116 117 newResult = new String[resultCount + 1]; 118 System.arraycopy(result, 0, newResult, 0, resultCount); 119 newResult[resultCount] = token; 120 121 return newResult; 122 } 123 }