1 /*
2 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Additionally licensed with:
19 *
20 * Licensed under the Apache License, Version 2.0 (the "License");
21 * you may not use this file except in compliance with the License.
22 * You may obtain a copy of the License at
23 *
24 * http://www.apache.org/licenses/LICENSE-2.0
25 *
26 * Unless required by applicable law or agreed to in writing, software
27 * distributed under the License is distributed on an "AS IS" BASIS,
28 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
29 * See the License for the specific language governing permissions and
30 * limitations under the License.
31 */
32 package org.spf4j.io;
33
34 import java.io.Closeable;
35 import java.io.Flushable;
36 import java.io.IOException;
37 import java.io.Writer;
38 import java.nio.CharBuffer;
39
40 /**
41 * Utility class to adapt a Appendable to a Writer.
42 * this is a faster version of guava: CharStreams.asWriter
43 * @author zoly
44 */
45 public final class AppendableWriter extends Writer {
46
47 private final Appendable appendable;
48
49 private final boolean flushable;
50
51 private boolean closed;
52
53 public AppendableWriter(final Appendable appendable) {
54 this.appendable = appendable;
55 this.flushable = appendable instanceof Flushable;
56 this.closed = false;
57 }
58
59 @Override
60 public void write(final char[] cbuf, final int off, final int len) throws IOException {
61 checkNotClosed();
62 /* Guava claims:
63 It turns out that creating a new String is usually as fast,
64 or faster than wrapping cbuf in a light-weight CharSequence.
65
66 Since I am suspicious of claims that do not make much sense and most developers write rubbish benchmarks
67 (Linus I start to be like you more and more),
68 I wrote a JMH benchmark, and the results are as expected the opposite:
69
70 Benchmark Mode Cnt Score Error Units
71 AppendableWriterBenchmark.guavaAppendable thrpt 10 10731.940 ± 427.258 ops/s
72 AppendableWriterBenchmark.spf4jAppendable thrpt 10 17613.093 ± 344.769 ops/s
73
74 Using a light weight wrapper is more than 50% faster!
75
76 See AppendableWriterBenchmark for more detail...
77
78 */
79 appendable.append(CharBuffer.wrap(cbuf), off, off + len);
80 }
81
82 @Override
83 public void write(final int c) throws IOException {
84 checkNotClosed();
85 appendable.append((char) c);
86 }
87
88 @Override
89 public Writer append(final char c) throws IOException {
90 checkNotClosed();
91 appendable.append(c);
92 return this;
93 }
94
95 @Override
96 public Writer append(final CharSequence csq, final int start, final int end) throws IOException {
97 checkNotClosed();
98 appendable.append(csq, start, end);
99 return this;
100 }
101
102 @Override
103 public Writer append(final CharSequence csq) throws IOException {
104 checkNotClosed();
105 appendable.append(csq);
106 return this;
107 }
108
109 @Override
110 public void write(final String str, final int off, final int len) throws IOException {
111 checkNotClosed();
112 appendable.append(str, off, off + len);
113 }
114
115 @Override
116 public void write(final String str) throws IOException {
117 appendable.append(str);
118 }
119
120 @Override
121 public void write(final char[] cbuf) throws IOException {
122 appendable.append(CharBuffer.wrap(cbuf));
123 }
124
125 @Override
126 public void flush() throws IOException {
127 checkNotClosed();
128 if (flushable) {
129 ((Flushable) appendable).flush();
130 }
131 }
132
133 private void checkNotClosed() throws IOException {
134 if (closed) {
135 throw new IOException("Cannot write to closed writer " + this);
136 }
137 }
138
139 @Override
140 public void close() throws IOException {
141 if (!closed) {
142 flush();
143 if (appendable instanceof Closeable) {
144 ((Closeable) appendable).close();
145 }
146 closed = true;
147 }
148 }
149
150 @Override
151 public String toString() {
152 return "AppendableWriter{" + "appendable=" + appendable + ", flushable=" + flushable + ", closed=" + closed + '}';
153 }
154
155 }