001// *************************************************************************************************************************** 002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * 003// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * 004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * 005// * with the License. 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 distributed under the License is distributed on an * 010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * 011// * specific language governing permissions and limitations under the License. * 012// *************************************************************************************************************************** 013package org.apache.juneau.internal; 014 015import java.io.*; 016 017/** 018 * Similar to {@link StringReader} except reads from a generic {@link CharSequenceReader}. 019 */ 020public final class CharSequenceReader extends BufferedReader { 021 022 private final CharSequence cs; 023 private String s; 024 private StringBuffer sb; 025 private StringBuilder sb2; 026 private int length; 027 private int next = 0; 028 029 /** 030 * Constructor. 031 * 032 * @param cs The char sequence to read from. Can be <jk>null</jk>. 033 */ 034 public CharSequenceReader(CharSequence cs) { 035 super(new StringReader(""), 1); // Does not actually use a reader. 036 if (cs == null) 037 cs = ""; 038 this.cs = cs; 039 if (cs instanceof String) 040 s = (String)cs; 041 else if (cs instanceof StringBuffer) 042 sb = (StringBuffer)cs; 043 else if (cs instanceof StringBuilder) 044 sb2 = (StringBuilder)cs; 045 this.length = cs.length(); 046 } 047 048 @Override /* Reader */ 049 public int read() { 050 if (next >= length) 051 return -1; 052 return cs.charAt(next++); 053 } 054 055 @Override /* Reader */ 056 public boolean markSupported() { 057 return false; 058 } 059 060 @Override /* Reader */ 061 public int read(final char[] cbuf, final int off, final int len) { 062 if (next >= length) 063 return -1; 064 int n = Math.min(length - next, len); 065 if (s != null) 066 s.getChars(next, next + n, cbuf, off); 067 else if (sb != null) 068 sb.getChars(next, next + n, cbuf, off); 069 else if (sb2 != null) 070 sb2.getChars(next, next + n, cbuf, off); 071 else { 072 for (int i = 0; i < n; i++) 073 cbuf[off+i] = cs.charAt(next+i); 074 } 075 next += n; 076 return n; 077 } 078 079 @Override /* Reader */ 080 public long skip(long ns) { 081 if (next >= length) 082 return 0; 083 long n = Math.min(length - next, ns); 084 n = Math.max(-next, n); 085 next += n; 086 return n; 087 } 088 089 @Override /* Reader */ 090 public void close() { 091 // no-op 092 } 093 094 @Override /* Object */ 095 public String toString() { 096 return cs.toString(); 097 } 098}