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Groovy example source code file (SynchronizedBytecodeBug.groovy)

This example Groovy source code file (SynchronizedBytecodeBug.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

groovytestcase, illegalmonitorstateexception, illegalmonitorstateexception, integer, integer, missingpropertyexception, object, object, synchronizedbytecodebug, synchronizedbytecodebug

The Groovy SynchronizedBytecodeBug.groovy source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package groovy.bugs

/**
 * @author Guillaume Laforge
 */
class SynchronizedBytecodeBug extends GroovyTestCase {

    /**
     * Groovy's bytecode associated with syncrhonized(foo) construct used to generate invalid bytecode
     * This test method shows that the standard wait()/notify() works.
     */
    void testSynchronized() {
        Integer foo = 0

        Thread.start{
            println "sleeping for a moment"
            sleep 1000
            println "slept and synchronizing from thread"
            synchronized(foo) {
                println "notifying"
                foo.notify()
                println "notified"
            }
        }

        println "synchronizing"
        synchronized(foo) {
            println "starting to wait"
            foo.wait()
            println "waited"
        }

        // if this point is reached, the test worked :-)
        assert true
    }
  
  /* more tests to ensure a monitor exit is done at the right place */
    
  void testBreakInSynchronized() {
    Object lock = new Object()
    while (true) {
        synchronized(lock) {
            break
        }
    }
    checkNotHavingAMonitor(lock)
  }
  
  void testContinueInSynchronized() {
    Object lock = new Object()  
    boolean b = true
    while (b) {
        synchronized(lock) {
            b = false
            continue
        }
    }
    checkNotHavingAMonitor(lock)
  }
  
  void testReturnInSynchronized() {
    Object lock = new Object()  
    methodWithReturn(lock)
    checkNotHavingAMonitor(lock)
  }
  
  def methodWithReturn(lock) {
    synchronized (lock) {
      return
    }
  }
  
  void testBreakInClosureWithSynchronized() {
    Object lock = new Object()
    def c = {
      while (true) {
          synchronized(lock) {
            break
          }
      }
      checkNotHavingAMonitor(lock)
    }
    c()
    checkNotHavingAMonitor(lock)
  }
  
  void testContinueInClosureWithSynchronized() {
    Object lock = new Object()
    def c = {
      boolean b = true
      while (b) {
          synchronized(lock) {
            b = false
            continue
          }
      }
      checkNotHavingAMonitor(lock)
    }
    c()
    checkNotHavingAMonitor(lock)
  }

  // GROOVY-4159
  void testExceptionInSynchronized() {
    def obj = 1
    try {
      synchronized(obj) {
        obj.e
      }
      assert false
    } catch (MissingPropertyException e) {
      assert true
    }
    checkNotHavingAMonitor(obj) 
  }
  
  def checkNotHavingAMonitor(Object lock){
    // if we call notify* or wait without having the
    // monitor, we get an exception.
    try {
      lock.notifyAll()
      assert false,"should have no monitor!"
    } catch (IllegalMonitorStateException imse) {
      assert true
    }
  }
}

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