1 /*

     2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. 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.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  */

    23 

    24 package nsk.share.jdi;

    25 

    26 import java.util.concurrent.locks.Lock;

    27 import java.util.concurrent.locks.ReentrantLock;

    28 import java.util.concurrent.locks.Condition;

    29 import java.util.concurrent.TimeUnit;

    30 

    31 import nsk.share.Failure;

    32 

    33 /**

    34  * Functions to set and wait for states in threads.

    35  * Used to sync main thread and debuggee thread.

    36  */

    37 public class ThreadState {

    38     private final Lock lock = new ReentrantLock();

    39     private final Condition cond = lock.newCondition();

    40     private volatile String currentState;

    41     private long timeoutMs;

    42 

    43     public ThreadState(String startState, long timeoutMs) {

    44         currentState = startState;

    45         this.timeoutMs = timeoutMs;

    46     }

    47 

    48     /**

    49      * Set new state.

    50      */

    51     public void setState(String newState) {

    52         lock.lock();

    53         try {

    54             log(MSG_SET_STATE, newState);

    55             currentState = newState;

    56             cond.signalAll();

    57         } finally {

    58             lock.unlock();

    59         }

    60     }

    61 

    62     /**

    63      * Wait for the specified state.

    64      * Throws Failure if timeout.

    65      */

    66     public void waitForState(String waitState) {

    67         lock.lock();

    68         try {

    69             log(MSG_WAIT_STATE, waitState);

    70             while (!currentState.equals(waitState)) {

    71                 if (!cond.await(timeoutMs, TimeUnit.MILLISECONDS)) {

    72                     throw new Failure(format(MSG_TIMEOUT, waitState));

    73                 }

    74             }

    75             log(MSG_GOT_STATE, waitState);

    76         } catch (InterruptedException e) {

    77             e.printStackTrace();

    78             throw new Failure(e);

    79         } finally {

    80             lock.unlock();

    81         }

    82     }

    83 

    84     /**

    85      * Simple helper that sets a new state and then wait for another state.

    86      */

    87     public void setAndWait(String newState, String waitState) {

    88         setState(newState);

    89         waitForState(waitState);

    90     }

    91 

    92     private static final String MSG_TIMEOUT = "ThreadState(thread='%s', state='%s') timeout waiting for %s";

    93     private static final String MSG_SET_STATE = "ThreadState(thread='%s', state='%s') set state to %s";

    94     private static final String MSG_WAIT_STATE = "ThreadState(thread='%s', state='%s') waiting for state %s";

    95     private static final String MSG_GOT_STATE = "ThreadState(thread='%s', state='%s') got state %s";

    96 

    97     private String format(String pattern, String state) {

    98         final String threadName = Thread.currentThread().getName();

    99         return String.format(pattern, threadName, currentState, state);

   100     }

   101 

   102     private void log(String pattern, String state) {

   103         System.out.println(format(pattern, state));

   104     }

   105 }