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.engine; 016 017 import org.apache.tapestry.IMarkupWriter; 018 import org.apache.tapestry.NestedMarkupWriter; 019 020 /** 021 * A {@link IMarkupWriter}that does absolutely <em>nothing</em>; this is used during the rewind 022 * phase of the request cycle when output is discarded anyway. 023 * 024 * @author Howard Lewis Ship, David Solis 025 * @since 0.2.9 026 */ 027 028 public class NullWriter implements NestedMarkupWriter 029 { 030 private static IMarkupWriter shared; 031 032 public static IMarkupWriter getSharedInstance() 033 { 034 if (shared == null) 035 shared = new NullWriter(); 036 037 return shared; 038 } 039 040 public String getBuffer() 041 { 042 return null; 043 } 044 045 public void printRaw(char[] buffer, int offset, int length) 046 { 047 } 048 049 public void printRaw(String value) 050 { 051 } 052 053 public void println() 054 { 055 } 056 057 public void print(char[] data, int offset, int length) 058 { 059 } 060 061 public void print(char value) 062 { 063 } 064 065 public void print(int value) 066 { 067 } 068 069 public void print(String value) 070 { 071 } 072 073 /** 074 * Returns <code>this</code>: since a NullWriter doesn't actually do anything, one is as good 075 * as another!. 076 */ 077 078 public NestedMarkupWriter getNestedWriter() 079 { 080 return this; 081 } 082 083 public String getContentType() 084 { 085 return null; 086 } 087 088 public void flush() 089 { 090 } 091 092 public void end() 093 { 094 } 095 096 public void end(String name) 097 { 098 } 099 100 public void comment(String value) 101 { 102 } 103 104 public void closeTag() 105 { 106 } 107 108 public void close() 109 { 110 } 111 112 /** 113 * Always returns false. 114 */ 115 116 public boolean checkError() 117 { 118 return false; 119 } 120 121 public void beginEmpty(String name) 122 { 123 } 124 125 public void begin(String name) 126 { 127 } 128 129 public void attribute(String name, int value) 130 { 131 } 132 133 public void attribute(String name, String value) 134 { 135 } 136 137 /** 138 * @see org.apache.tapestry.IMarkupWriter#attribute(java.lang.String, boolean) 139 * @since 3.0 140 */ 141 142 public void attribute(String name, boolean value) 143 { 144 } 145 146 /** 147 * @see org.apache.tapestry.IMarkupWriter#attributeRaw(java.lang.String, java.lang.String) 148 * @since 3.0 149 */ 150 151 public void attributeRaw(String name, String value) 152 { 153 } 154 155 public void print(char[] data, int offset, int length, boolean raw) 156 { 157 } 158 159 public void print(String value, boolean raw) 160 { 161 } 162 }