J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2007 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.lang; |
| 27 | |
| 28 | import java.io.*; |
| 29 | |
| 30 | /** |
| 31 | * The {@link ProcessBuilder#start()} and |
| 32 | * {@link Runtime#exec(String[],String[],File) Runtime.exec} |
| 33 | * methods create a native process and return an instance of a |
| 34 | * subclass of {@code Process} that can be used to control the process |
| 35 | * and obtain information about it. The class {@code Process} |
| 36 | * provides methods for performing input from the process, performing |
| 37 | * output to the process, waiting for the process to complete, |
| 38 | * checking the exit status of the process, and destroying (killing) |
| 39 | * the process. |
| 40 | * |
| 41 | * <p>The methods that create processes may not work well for special |
| 42 | * processes on certain native platforms, such as native windowing |
| 43 | * processes, daemon processes, Win16/DOS processes on Microsoft |
| 44 | * Windows, or shell scripts. The created subprocess does not have |
| 45 | * its own terminal or console. All its standard I/O (i.e. stdin, |
| 46 | * stdout, stderr) operations will be redirected to the parent process |
| 47 | * through three streams |
| 48 | * ({@link #getOutputStream()}, |
| 49 | * {@link #getInputStream()}, |
| 50 | * {@link #getErrorStream()}). |
| 51 | * The parent process uses these streams to feed input to and get output |
| 52 | * from the subprocess. Because some native platforms only provide |
| 53 | * limited buffer size for standard input and output streams, failure |
| 54 | * to promptly write the input stream or read the output stream of |
| 55 | * the subprocess may cause the subprocess to block, and even deadlock. |
| 56 | * |
| 57 | * <p>The subprocess is not killed when there are no more references to |
| 58 | * the {@code Process} object, but rather the subprocess |
| 59 | * continues executing asynchronously. |
| 60 | * |
| 61 | * <p>There is no requirement that a process represented by a {@code |
| 62 | * Process} object execute asynchronously or concurrently with respect |
| 63 | * to the Java process that owns the {@code Process} object. |
| 64 | * |
| 65 | * @author unascribed |
| 66 | * @see ProcessBuilder |
| 67 | * @since JDK1.0 |
| 68 | */ |
| 69 | public abstract class Process { |
| 70 | /** |
| 71 | * Returns the output stream connected to the normal input of the |
| 72 | * subprocess. Output to the stream is piped into the standard |
| 73 | * input stream of the process represented by this {@code Process} |
| 74 | * object. |
| 75 | * |
| 76 | * <p>Implementation note: It is a good idea for the returned |
| 77 | * output stream to be buffered. |
| 78 | * |
| 79 | * @return the output stream connected to the normal input of the |
| 80 | * subprocess |
| 81 | */ |
| 82 | abstract public OutputStream getOutputStream(); |
| 83 | |
| 84 | /** |
| 85 | * Returns the input stream connected to the normal output of the |
| 86 | * subprocess. The stream obtains data piped from the standard |
| 87 | * output stream of the process represented by this {@code |
| 88 | * Process} object. |
| 89 | * |
| 90 | * <p>Implementation note: It is a good idea for the returned |
| 91 | * input stream to be buffered. |
| 92 | * |
| 93 | * @return the input stream connected to the normal output of the |
| 94 | * subprocess |
| 95 | * @see ProcessBuilder#redirectErrorStream() |
| 96 | */ |
| 97 | abstract public InputStream getInputStream(); |
| 98 | |
| 99 | /** |
| 100 | * Returns the input stream connected to the error output stream of |
| 101 | * the subprocess. The stream obtains data piped from the error |
| 102 | * output stream of the process represented by this {@code Process} |
| 103 | * object. |
| 104 | * |
| 105 | * <p>Implementation note: It is a good idea for the returned |
| 106 | * input stream to be buffered. |
| 107 | * |
| 108 | * @return the input stream connected to the error output stream of |
| 109 | * the subprocess |
| 110 | * @see ProcessBuilder#redirectErrorStream() |
| 111 | */ |
| 112 | abstract public InputStream getErrorStream(); |
| 113 | |
| 114 | /** |
| 115 | * Causes the current thread to wait, if necessary, until the |
| 116 | * process represented by this {@code Process} object has |
| 117 | * terminated. This method returns immediately if the subprocess |
| 118 | * has already terminated. If the subprocess has not yet |
| 119 | * terminated, the calling thread will be blocked until the |
| 120 | * subprocess exits. |
| 121 | * |
| 122 | * @return the exit value of the subprocess represented by this |
| 123 | * {@code Process} object. By convention, the value |
| 124 | * {@code 0} indicates normal termination. |
| 125 | * @throws InterruptedException if the current thread is |
| 126 | * {@linkplain Thread#interrupt() interrupted} by another |
| 127 | * thread while it is waiting, then the wait is ended and |
| 128 | * an {@link InterruptedException} is thrown. |
| 129 | */ |
| 130 | abstract public int waitFor() throws InterruptedException; |
| 131 | |
| 132 | /** |
| 133 | * Returns the exit value for the subprocess. |
| 134 | * |
| 135 | * @return the exit value of the subprocess represented by this |
| 136 | * {@code Process} object. By convention, the value |
| 137 | * {@code 0} indicates normal termination. |
| 138 | * @throws IllegalThreadStateException if the subprocess represented |
| 139 | * by this {@code Process} object has not yet terminated |
| 140 | */ |
| 141 | abstract public int exitValue(); |
| 142 | |
| 143 | /** |
| 144 | * Kills the subprocess. The subprocess represented by this |
| 145 | * {@code Process} object is forcibly terminated. |
| 146 | */ |
| 147 | abstract public void destroy(); |
| 148 | } |