| /* |
| * Copyright (c) 2014, 2017, 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.time.Duration; |
| import java.time.Instant; |
| import java.util.Optional; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.stream.Stream; |
| |
| /** |
| * ProcessHandle identifies and provides control of native processes. Each |
| * individual process can be monitored for liveness, list its children, |
| * get information about the process or destroy it. |
| * By comparison, {@link java.lang.Process Process} instances were started |
| * by the current process and additionally provide access to the process |
| * input, output, and error streams. |
| * <p> |
| * The native process ID is an identification number that the |
| * operating system assigns to the process. |
| * The range for process id values is dependent on the operating system. |
| * For example, an embedded system might use a 16-bit value. |
| * Status information about a process is retrieved from the native system |
| * and may change asynchronously; processes may be created or terminate |
| * spontaneously. |
| * The time between when a process terminates and the process id |
| * is reused for a new process is unpredictable. |
| * Race conditions can exist between checking the status of a process and |
| * acting upon it. When using ProcessHandles avoid assumptions |
| * about the liveness or identity of the underlying process. |
| * <p> |
| * Each ProcessHandle identifies and allows control of a process in the native |
| * system. ProcessHandles are returned from the factory methods {@link #current()}, |
| * {@link #of(long)}, |
| * {@link #children}, {@link #descendants}, {@link #parent()} and |
| * {@link #allProcesses()}. |
| * <p> |
| * The {@link Process} instances created by {@link ProcessBuilder} can be queried |
| * for a ProcessHandle that provides information about the Process. |
| * ProcessHandle references should not be freely distributed. |
| * |
| * <p> |
| * A {@link java.util.concurrent.CompletableFuture} available from {@link #onExit} |
| * can be used to wait for process termination, and possibly trigger dependent |
| * actions. |
| * <p> |
| * The factory methods limit access to ProcessHandles using the |
| * SecurityManager checking the {@link RuntimePermission RuntimePermission("manageProcess")}. |
| * The ability to control processes is also restricted by the native system, |
| * ProcessHandle provides no more access to, or control over, the native process |
| * than would be allowed by a native application. |
| * |
| * @implSpec |
| * In the case where ProcessHandles cannot be supported then the factory |
| * methods must consistently throw {@link java.lang.UnsupportedOperationException}. |
| * The methods of this class throw {@link java.lang.UnsupportedOperationException} |
| * if the operating system does not allow access to query or kill a process. |
| * |
| * <p> |
| * The {@code ProcessHandle} static factory methods return instances that are |
| * <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>, |
| * immutable and thread-safe. |
| * Use of identity-sensitive operations (including reference equality |
| * ({@code ==}), identity hash code, or synchronization) on these instances of |
| * {@code ProcessHandle} may have unpredictable results and should be avoided. |
| * Use {@link #equals(Object) equals} or |
| * {@link #compareTo(ProcessHandle) compareTo} methods to compare ProcessHandles. |
| * |
| * @see Process |
| * @since 9 |
| */ |
| public interface ProcessHandle extends Comparable<ProcessHandle> { |
| |
| /** |
| * Returns the native process ID of the process. The native process ID is an |
| * identification number that the operating system assigns to the process. |
| * The operating system may reuse the process ID after a process terminates. |
| * Use {@link #equals(Object) equals} or |
| * {@link #compareTo(ProcessHandle) compareTo} to compare ProcessHandles. |
| * |
| * @return the native process ID of the process |
| * @throws UnsupportedOperationException if the implementation |
| * does not support this operation |
| */ |
| long pid(); |
| |
| /** |
| * Returns an {@code Optional<ProcessHandle>} for an existing native process. |
| * |
| * @param pid a native process ID |
| * @return an {@code Optional<ProcessHandle>} of the PID for the process; |
| * the {@code Optional} is empty if the process does not exist |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| * @throws UnsupportedOperationException if the implementation |
| * does not support this operation |
| */ |
| public static Optional<ProcessHandle> of(long pid) { |
| return ProcessHandleImpl.get(pid); |
| } |
| |
| /** |
| * Returns a ProcessHandle for the current process. The ProcessHandle cannot be |
| * used to destroy the current process, use {@link System#exit System.exit} instead. |
| * |
| * @return a ProcessHandle for the current process |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| * @throws UnsupportedOperationException if the implementation |
| * does not support this operation |
| */ |
| public static ProcessHandle current() { |
| return ProcessHandleImpl.current(); |
| } |
| |
| /** |
| * Returns an {@code Optional<ProcessHandle>} for the parent process. |
| * Note that Processes in a zombie state usually don't have a parent. |
| * |
| * @return an {@code Optional<ProcessHandle>} of the parent process; |
| * the {@code Optional} is empty if the child process does not have a parent |
| * or if the parent is not available, possibly due to operating system limitations |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| */ |
| Optional<ProcessHandle> parent(); |
| |
| /** |
| * Returns a snapshot of the current direct children of the process. |
| * The {@link #parent} of a direct child process is the process. |
| * Typically, a process that is {@link #isAlive not alive} has no children. |
| * <p> |
| * <em>Note that processes are created and terminate asynchronously. |
| * There is no guarantee that a process is {@link #isAlive alive}. |
| * </em> |
| * |
| * @return a sequential Stream of ProcessHandles for processes that are |
| * direct children of the process |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| */ |
| Stream<ProcessHandle> children(); |
| |
| /** |
| * Returns a snapshot of the descendants of the process. |
| * The descendants of a process are the children of the process |
| * plus the descendants of those children, recursively. |
| * Typically, a process that is {@link #isAlive not alive} has no children. |
| * <p> |
| * <em>Note that processes are created and terminate asynchronously. |
| * There is no guarantee that a process is {@link #isAlive alive}. |
| * </em> |
| * |
| * @return a sequential Stream of ProcessHandles for processes that |
| * are descendants of the process |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| */ |
| Stream<ProcessHandle> descendants(); |
| |
| /** |
| * Returns a snapshot of all processes visible to the current process. |
| * <p> |
| * <em>Note that processes are created and terminate asynchronously. There |
| * is no guarantee that a process in the stream is alive or that no other |
| * processes may have been created since the inception of the snapshot. |
| * </em> |
| * |
| * @return a Stream of ProcessHandles for all processes |
| * @throws SecurityException if a security manager has been installed and |
| * it denies RuntimePermission("manageProcess") |
| * @throws UnsupportedOperationException if the implementation |
| * does not support this operation |
| */ |
| static Stream<ProcessHandle> allProcesses() { |
| return ProcessHandleImpl.children(0); |
| } |
| |
| /** |
| * Returns a snapshot of information about the process. |
| * |
| * <p> A {@link ProcessHandle.Info} instance has accessor methods that return |
| * information about the process if it is available. |
| * |
| * @return a snapshot of information about the process, always non-null |
| */ |
| Info info(); |
| |
| /** |
| * Information snapshot about the process. |
| * The attributes of a process vary by operating system and are not available |
| * in all implementations. Information about processes is limited |
| * by the operating system privileges of the process making the request. |
| * The return types are {@code Optional<T>} allowing explicit tests |
| * and actions if the value is available. |
| * @since 9 |
| */ |
| public interface Info { |
| /** |
| * Returns the executable pathname of the process. |
| * |
| * @return an {@code Optional<String>} of the executable pathname |
| * of the process |
| */ |
| public Optional<String> command(); |
| |
| /** |
| * Returns the command line of the process. |
| * <p> |
| * If {@link #command command()} and {@link #arguments arguments()} return |
| * non-empty optionals, this is simply a convenience method which concatenates |
| * the values of the two functions separated by spaces. Otherwise it will return a |
| * best-effort, platform dependent representation of the command line. |
| * |
| * @apiNote Note that the returned executable pathname and the |
| * arguments may be truncated on some platforms due to system |
| * limitations. |
| * <p> |
| * The executable pathname may contain only the |
| * name of the executable without the full path information. |
| * It is undecideable whether white space separates different |
| * arguments or is part of a single argument. |
| * |
| * @return an {@code Optional<String>} of the command line |
| * of the process |
| */ |
| public Optional<String> commandLine(); |
| |
| /** |
| * Returns an array of Strings of the arguments of the process. |
| * |
| * @apiNote On some platforms, native applications are free to change |
| * the arguments array after startup and this method may only |
| * show the changed values. |
| * |
| * @return an {@code Optional<String[]>} of the arguments of the process |
| */ |
| public Optional<String[]> arguments(); |
| |
| /** |
| * Returns the start time of the process. |
| * |
| * @return an {@code Optional<Instant>} of the start time of the process |
| */ |
| public Optional<Instant> startInstant(); |
| |
| /** |
| * Returns the total cputime accumulated of the process. |
| * |
| * @return an {@code Optional<Duration>} for the accumulated total cputime |
| */ |
| public Optional<Duration> totalCpuDuration(); |
| |
| /** |
| * Return the user of the process. |
| * |
| * @return an {@code Optional<String>} for the user of the process |
| */ |
| public Optional<String> user(); |
| } |
| |
| /** |
| * Returns a {@code CompletableFuture<ProcessHandle>} for the termination |
| * of the process. |
| * The {@link java.util.concurrent.CompletableFuture} provides the ability |
| * to trigger dependent functions or actions that may be run synchronously |
| * or asynchronously upon process termination. |
| * When the process has terminated the CompletableFuture is |
| * {@link java.util.concurrent.CompletableFuture#complete completed} regardless |
| * of the exit status of the process. |
| * The {@code onExit} method can be called multiple times to invoke |
| * independent actions when the process exits. |
| * <p> |
| * Calling {@code onExit().get()} waits for the process to terminate and returns |
| * the ProcessHandle. The future can be used to check if the process is |
| * {@link java.util.concurrent.CompletableFuture#isDone done} or to |
| * {@link java.util.concurrent.Future#get() wait} for it to terminate. |
| * {@link java.util.concurrent.Future#cancel(boolean) Cancelling} |
| * the CompleteableFuture does not affect the Process. |
| * @apiNote |
| * The process may be observed to have terminated with {@link #isAlive} |
| * before the ComputableFuture is completed and dependent actions are invoked. |
| * |
| * @return a new {@code CompletableFuture<ProcessHandle>} for the ProcessHandle |
| * |
| * @throws IllegalStateException if the process is the current process |
| */ |
| CompletableFuture<ProcessHandle> onExit(); |
| |
| /** |
| * Returns {@code true} if the implementation of {@link #destroy} |
| * normally terminates the process. |
| * Returns {@code false} if the implementation of {@code destroy} |
| * forcibly and immediately terminates the process. |
| * |
| * @return {@code true} if the implementation of {@link #destroy} |
| * normally terminates the process; |
| * otherwise, {@link #destroy} forcibly terminates the process |
| */ |
| boolean supportsNormalTermination(); |
| |
| /** |
| * Requests the process to be killed. |
| * Whether the process represented by this {@code ProcessHandle} object is |
| * {@link #supportsNormalTermination normally terminated} or not is |
| * implementation dependent. |
| * Forcible process destruction is defined as the immediate termination of the |
| * process, whereas normal termination allows the process to shut down cleanly. |
| * If the process is not alive, no action is taken. |
| * The operating system access controls may prevent the process |
| * from being killed. |
| * <p> |
| * The {@link java.util.concurrent.CompletableFuture} from {@link #onExit} is |
| * {@link java.util.concurrent.CompletableFuture#complete completed} |
| * when the process has terminated. |
| * <p> |
| * Note: The process may not terminate immediately. |
| * For example, {@code isAlive()} may return true for a brief period |
| * after {@code destroy()} is called. |
| * |
| * @return {@code true} if termination was successfully requested, |
| * otherwise {@code false} |
| * @throws IllegalStateException if the process is the current process |
| */ |
| boolean destroy(); |
| |
| /** |
| * Requests the process to be killed forcibly. |
| * The process represented by this {@code ProcessHandle} object is |
| * forcibly terminated. |
| * Forcible process destruction is defined as the immediate termination of the |
| * process, whereas normal termination allows the process to shut down cleanly. |
| * If the process is not alive, no action is taken. |
| * The operating system access controls may prevent the process |
| * from being killed. |
| * <p> |
| * The {@link java.util.concurrent.CompletableFuture} from {@link #onExit} is |
| * {@link java.util.concurrent.CompletableFuture#complete completed} |
| * when the process has terminated. |
| * <p> |
| * Note: The process may not terminate immediately. |
| * For example, {@code isAlive()} may return true for a brief period |
| * after {@code destroyForcibly()} is called. |
| * |
| * @return {@code true} if termination was successfully requested, |
| * otherwise {@code false} |
| * @throws IllegalStateException if the process is the current process |
| */ |
| boolean destroyForcibly(); |
| |
| /** |
| * Tests whether the process represented by this {@code ProcessHandle} is alive. |
| * Process termination is implementation and operating system specific. |
| * The process is considered alive as long as the PID is valid. |
| * |
| * @return {@code true} if the process represented by this |
| * {@code ProcessHandle} object has not yet terminated |
| */ |
| boolean isAlive(); |
| |
| /** |
| * Returns a hash code value for this ProcessHandle. |
| * The hashcode value follows the general contract for {@link Object#hashCode()}. |
| * The value is a function of the {@link #pid pid()} value and |
| * may be a function of additional information to uniquely identify the process. |
| * If two ProcessHandles are equal according to the {@link #equals(Object) equals} |
| * method, then calling the hashCode method on each of the two objects |
| * must produce the same integer result. |
| * |
| * @return a hash code value for this object |
| */ |
| @Override |
| int hashCode(); |
| |
| /** |
| * Returns {@code true} if {@code other} object is non-null, is of the |
| * same implementation, and represents the same system process; |
| * otherwise it returns {@code false}. |
| * @implNote |
| * It is implementation specific whether ProcessHandles with the same PID |
| * represent the same system process. ProcessHandle implementations |
| * should contain additional information to uniquely identify the process. |
| * For example, the start time of the process could be used |
| * to determine if the PID has been re-used. |
| * The implementation of {@code equals} should return {@code true} for two |
| * ProcessHandles with the same PID unless there is information to |
| * distinguish them. |
| * |
| * @param other another object |
| * @return {@code true} if the {@code other} object is non-null, |
| * is of the same implementation class and represents |
| * the same system process; otherwise returns {@code false} |
| */ |
| @Override |
| boolean equals(Object other); |
| |
| /** |
| * Compares this ProcessHandle with the specified ProcessHandle for order. |
| * The order is not specified, but is consistent with {@link Object#equals}, |
| * which returns {@code true} if and only if two instances of ProcessHandle |
| * are of the same implementation and represent the same system process. |
| * Comparison is only supported among objects of same implementation. |
| * If attempt is made to mutually compare two different implementations |
| * of {@link ProcessHandle}s, {@link ClassCastException} is thrown. |
| * |
| * @param other the ProcessHandle to be compared |
| * @return a negative integer, zero, or a positive integer as this object |
| * is less than, equal to, or greater than the specified object. |
| * @throws NullPointerException if the specified object is null |
| * @throws ClassCastException if the specified object is not of same class |
| * as this object |
| */ |
| @Override |
| int compareTo(ProcessHandle other); |
| |
| } |