| /* |
| * Copyright (c) 1995, 2012, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang; |
| |
| import java.io.*; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * The {@link ProcessBuilder#start()} and |
| * {@link Runtime#exec(String[],String[],File) Runtime.exec} |
| * methods create a native process and return an instance of a |
| * subclass of {@code Process} that can be used to control the process |
| * and obtain information about it. The class {@code Process} |
| * provides methods for performing input from the process, performing |
| * output to the process, waiting for the process to complete, |
| * checking the exit status of the process, and destroying (killing) |
| * the process. |
| * |
| * <p>The methods that create processes may not work well for special |
| * processes on certain native platforms, such as native windowing |
| * processes, daemon processes, Win16/DOS processes on Microsoft |
| * Windows, or shell scripts. |
| * |
| * <p>By default, the created subprocess does not have its own terminal |
| * or console. All its standard I/O (i.e. stdin, stdout, stderr) |
| * operations will be redirected to the parent process, where they can |
| * be accessed via the streams obtained using the methods |
| * {@link #getOutputStream()}, |
| * {@link #getInputStream()}, and |
| * {@link #getErrorStream()}. |
| * The parent process uses these streams to feed input to and get output |
| * from the subprocess. Because some native platforms only provide |
| * limited buffer size for standard input and output streams, failure |
| * to promptly write the input stream or read the output stream of |
| * the subprocess may cause the subprocess to block, or even deadlock. |
| * |
| * <p>Where desired, <a href="ProcessBuilder.html#redirect-input"> |
| * subprocess I/O can also be redirected</a> |
| * using methods of the {@link ProcessBuilder} class. |
| * |
| * <p>The subprocess is not killed when there are no more references to |
| * the {@code Process} object, but rather the subprocess |
| * continues executing asynchronously. |
| * |
| * <p>There is no requirement that a process represented by a {@code |
| * Process} object execute asynchronously or concurrently with respect |
| * to the Java process that owns the {@code Process} object. |
| * |
| * <p>As of 1.5, {@link ProcessBuilder#start()} is the preferred way |
| * to create a {@code Process}. |
| * |
| * @since JDK1.0 |
| */ |
| public abstract class Process { |
| /** |
| * Returns the output stream connected to the normal input of the |
| * subprocess. Output to the stream is piped into the standard |
| * input of the process represented by this {@code Process} object. |
| * |
| * <p>If the standard input of the subprocess has been redirected using |
| * {@link ProcessBuilder#redirectInput(Redirect) |
| * ProcessBuilder.redirectInput} |
| * then this method will return a |
| * <a href="ProcessBuilder.html#redirect-input">null output stream</a>. |
| * |
| * <p>Implementation note: It is a good idea for the returned |
| * output stream to be buffered. |
| * |
| * @return the output stream connected to the normal input of the |
| * subprocess |
| */ |
| public abstract OutputStream getOutputStream(); |
| |
| /** |
| * Returns the input stream connected to the normal output of the |
| * subprocess. The stream obtains data piped from the standard |
| * output of the process represented by this {@code Process} object. |
| * |
| * <p>If the standard output of the subprocess has been redirected using |
| * {@link ProcessBuilder#redirectOutput(Redirect) |
| * ProcessBuilder.redirectOutput} |
| * then this method will return a |
| * <a href="ProcessBuilder.html#redirect-output">null input stream</a>. |
| * |
| * <p>Otherwise, if the standard error of the subprocess has been |
| * redirected using |
| * {@link ProcessBuilder#redirectErrorStream(boolean) |
| * ProcessBuilder.redirectErrorStream} |
| * then the input stream returned by this method will receive the |
| * merged standard output and the standard error of the subprocess. |
| * |
| * <p>Implementation note: It is a good idea for the returned |
| * input stream to be buffered. |
| * |
| * @return the input stream connected to the normal output of the |
| * subprocess |
| */ |
| public abstract InputStream getInputStream(); |
| |
| /** |
| * Returns the input stream connected to the error output of the |
| * subprocess. The stream obtains data piped from the error output |
| * of the process represented by this {@code Process} object. |
| * |
| * <p>If the standard error of the subprocess has been redirected using |
| * {@link ProcessBuilder#redirectError(Redirect) |
| * ProcessBuilder.redirectError} or |
| * {@link ProcessBuilder#redirectErrorStream(boolean) |
| * ProcessBuilder.redirectErrorStream} |
| * then this method will return a |
| * <a href="ProcessBuilder.html#redirect-output">null input stream</a>. |
| * |
| * <p>Implementation note: It is a good idea for the returned |
| * input stream to be buffered. |
| * |
| * @return the input stream connected to the error output of |
| * the subprocess |
| */ |
| public abstract InputStream getErrorStream(); |
| |
| /** |
| * Causes the current thread to wait, if necessary, until the |
| * process represented by this {@code Process} object has |
| * terminated. This method returns immediately if the subprocess |
| * has already terminated. If the subprocess has not yet |
| * terminated, the calling thread will be blocked until the |
| * subprocess exits. |
| * |
| * @return the exit value of the subprocess represented by this |
| * {@code Process} object. By convention, the value |
| * {@code 0} indicates normal termination. |
| * @throws InterruptedException if the current thread is |
| * {@linkplain Thread#interrupt() interrupted} by another |
| * thread while it is waiting, then the wait is ended and |
| * an {@link InterruptedException} is thrown. |
| */ |
| public abstract int waitFor() throws InterruptedException; |
| |
| /** |
| * Causes the current thread to wait, if necessary, until the |
| * subprocess represented by this {@code Process} object has |
| * terminated, or the specified waiting time elapses. |
| * |
| * <p>If the subprocess has already terminated then this method returns |
| * immediately with the value {@code true}. If the process has not |
| * terminated and the timeout value is less than, or equal to, zero, then |
| * this method returns immediately with the value {@code false}. |
| * |
| * <p>The default implementation of this methods polls the {@code exitValue} |
| * to check if the process has terminated. Concrete implementations of this |
| * class are strongly encouraged to override this method with a more |
| * efficient implementation. |
| * |
| * @param timeout the maximum time to wait |
| * @param unit the time unit of the {@code timeout} argument |
| * @return {@code true} if the subprocess has exited and {@code false} if |
| * the waiting time elapsed before the subprocess has exited. |
| * @throws InterruptedException if the current thread is interrupted |
| * while waiting. |
| * @throws NullPointerException if unit is null |
| * @since 1.8 |
| */ |
| public boolean waitFor(long timeout, TimeUnit unit) |
| throws InterruptedException |
| { |
| long startTime = System.nanoTime(); |
| long rem = unit.toNanos(timeout); |
| |
| do { |
| try { |
| exitValue(); |
| return true; |
| } catch(IllegalThreadStateException ex) { |
| if (rem > 0) |
| Thread.sleep( |
| Math.min(TimeUnit.NANOSECONDS.toMillis(rem) + 1, 100)); |
| } |
| rem = unit.toNanos(timeout) - (System.nanoTime() - startTime); |
| } while (rem > 0); |
| return false; |
| } |
| |
| /** |
| * Returns the exit value for the subprocess. |
| * |
| * @return the exit value of the subprocess represented by this |
| * {@code Process} object. By convention, the value |
| * {@code 0} indicates normal termination. |
| * @throws IllegalThreadStateException if the subprocess represented |
| * by this {@code Process} object has not yet terminated |
| */ |
| public abstract int exitValue(); |
| |
| /** |
| * Kills the subprocess. Whether the subprocess represented by this |
| * {@code Process} object is forcibly terminated or not is |
| * implementation dependent. |
| */ |
| public abstract void destroy(); |
| |
| /** |
| * Kills the subprocess. The subprocess represented by this |
| * {@code Process} object is forcibly terminated. |
| * |
| * <p>The default implementation of this method invokes {@link #destroy} |
| * and so may not forcibly terminate the process. Concrete implementations |
| * of this class are strongly encouraged to override this method with a |
| * compliant implementation. Invoking this method on {@code Process} |
| * objects returned by {@link ProcessBuilder#start} and |
| * {@link Runtime#exec} will forcibly terminate the process. |
| * |
| * <p>Note: The subprocess may not terminate immediately. |
| * i.e. {@code isAlive()} may return true for a brief period |
| * after {@code destroyForcibly()} is called. This method |
| * may be chained to {@code waitFor()} if needed. |
| * |
| * @return the {@code Process} object representing the |
| * subprocess to be forcibly destroyed. |
| * @since 1.8 |
| */ |
| public Process destroyForcibly() { |
| destroy(); |
| return this; |
| } |
| |
| /** |
| * Tests whether the subprocess represented by this {@code Process} is |
| * alive. |
| * |
| * @return {@code true} if the subprocess represented by this |
| * {@code Process} object has not yet terminated. |
| * @since 1.8 |
| */ |
| public boolean isAlive() { |
| try { |
| exitValue(); |
| return false; |
| } catch(IllegalThreadStateException e) { |
| return true; |
| } |
| } |
| } |