--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/lang/ProcessHandle.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,438 @@
+/*
+ * 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);
+
+}