001 /*
002 * This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 * This file is licensed to You under the Eclipse Public License (EPL);
005 * You may not use this file except in compliance with the License. You
006 * may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 * See the COPYRIGHT.txt file distributed with this work for information
011 * regarding copyright ownership.
012 */
013 package org.jikesrvm;
014
015 import java.io.PrintStream;
016 import java.io.PrintWriter;
017 import org.jikesrvm.classloader.Atom;
018 import org.jikesrvm.classloader.RVMMember;
019
020 /**
021 * The subclasses of PrintContainer all implement the {@link PrintLN}
022 * interface. They are used by our {@link java.lang.Throwable} to print stack
023 * traces; it lets one use a single class to operate on {@link PrintWriter}
024 * and {@link PrintStream} output streams and for the {@link VM#sysWrite}
025 * output method.
026 *
027 * <p> We use it so we can print stack traces without having to provide
028 * multiple versions of each method, one for each kind of output stream.
029 */
030 public final class PrintContainer {
031 /** Can not be instantiated. */
032 private PrintContainer() {}
033
034 /** Print via PrintWriter */
035 private static class WithPrintWriter extends PrintLN {
036 private PrintWriter out;
037
038 WithPrintWriter(PrintWriter out) {
039 this.out = out;
040 }
041
042 @Override
043 public void flush() {
044 out.flush();
045 }
046
047 @Override
048 public void println() {
049 out.println();
050 }
051
052 @Override
053 public void print(String s) {
054 if (s == null) {
055 s = "(*null String pointer*)";
056 }
057 out.print(s);
058 }
059
060 @Override
061 public void print(char c) {
062 out.print(c);
063 }
064 }
065
066 /** Print via PrintStream */
067 private static class WithPrintStream extends PrintLN {
068 private PrintStream out;
069
070 WithPrintStream(PrintStream out) {
071 this.out = out;
072 }
073
074 @Override
075 public boolean isSystemErr() {
076 return this.out == System.err;
077 }
078
079 @Override
080 public void flush() {
081 out.flush();
082 }
083
084 @Override
085 public void println() {
086 out.println();
087 }
088
089 @Override
090 public void print(String s) {
091 if (s == null) {
092 s = "(*null String pointer*)";
093 }
094 out.print(s);
095 }
096
097 @Override
098 public void print(char c) {
099 out.print(c);
100 }
101 }
102
103 public static PrintLN get(PrintStream out) {
104 return new WithPrintStream(out);
105 }
106
107 public static PrintLN get(PrintWriter out) {
108 return new WithPrintWriter(out);
109 }
110
111 // Keep this one ready to go at all times :)
112 public static final PrintLN readyPrinter = new WithSysWrite();
113
114 /** This (nested) class does printing via {@link VM#sysWrite} */
115 private static class WithSysWrite extends PrintLN {
116 /** This doesn't carry any state, but we have a constructor so that we can
117 * pass an instance of this to something expecting a {@link PrintLN} . */
118 WithSysWrite() {}
119
120 @Override
121 public boolean isSysWrite() {
122 return true;
123 }
124
125 @Override
126 public void flush() {
127 }
128
129 @Override
130 public void println() {
131 VM.sysWriteln();
132 }
133
134 @Override
135 public void print(String s) {
136 if (s == null) {
137 s = "(*null String pointer*)";
138 }
139
140 VM.sysWrite(s);
141 }
142
143 @Override
144 public void println(String s) {
145 print(s);
146 println();
147 }
148
149 @Override
150 public void print(int i) {
151 VM.sysWrite(i);
152 }
153
154 @Override
155 public void printHex(int i) {
156 VM.sysWriteHex(i);
157 }
158
159 @Override
160 public void print(char c) {
161 VM.sysWrite(c);
162 }
163
164 @Override
165 public void print(RVMMember m) {
166 VM.sysWrite(m);
167 }
168
169 @Override
170 public void print(Atom a) {
171 VM.sysWrite(a);
172 }
173 }
174 }
175