// GPars - Groovy Parallel Systems
//
// Copyright © 2008-2012 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 org.codehaus.gpars.javademo;
import groovyx.gpars.MessagingRunnable;
import groovyx.gpars.dataflow.DataflowVariable;
import groovyx.gpars.dataflow.Promise;
import groovyx.gpars.group.DefaultPGroup;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import static org.junit.Assert.assertEquals;
@SuppressWarnings({"MagicNumber"})
public class DataflowTaskTest {
@Test
public void testDataflowVariable() throws Throwable {
final List<String> logMessages = new ArrayList<String>();
final DefaultPGroup group = new DefaultPGroup(10);
// variable can be assigned once only, read allowed multiple times
final DataflowVariable<Integer> a = new DataflowVariable<Integer>();
// group.task will use thread from pool and uses it to execute value bind
group.task(new Runnable() {
public void run() {
// first thread binding value succeeds, other attempts would fail with IllegalStateException
logMessages.add("Value bound");
a.bind(10);
}
});
// group.task will use thread from pool and uses it to execute call method
final Promise<?> result = group.task(new Callable() {
public Object call() throws Exception {
// getVal will wait for the value to be assigned
final int result = a.getVal() + 10;
logMessages.add("Value calculated");
return result;
}
});
// Specify, what will happen when value is bound
result.whenBound(new MessagingRunnable<Integer>() {
@Override
protected void doRun(final Integer resultValue) {
logMessages.add("Result calculated");
assertEquals("Result value invalid", 20L, resultValue.intValue());
assertEquals("Wrong order of calls", Arrays.asList("Value bound", "Value calculated", "Result calculated"), logMessages);
}
});
System.out.println("result = " + result.get());
}
}