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/*******************************************************************************
* Copyright (c) 2011 Wind River Systems and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* Wind River Systems - initial API and implementation
*******************************************************************************/
//#ifdef exercises
package org.eclipse.cdt.examples.dsf.dataviewer;
//#else
//#package org.eclipse.cdt.examples.dsf.dataviewer.answers;
//#endif
import java.util.Arrays;
import java.util.concurrent.TimeUnit;
import org.eclipse.cdt.dsf.concurrent.CountingRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.DsfExecutor;
import org.eclipse.cdt.dsf.concurrent.ImmediateExecutor;
import org.eclipse.cdt.dsf.concurrent.RequestMonitor;
/**
* A data generator which performs a sum computation on data retrieved from a
* number of other data generators. The data retrieval from other generators
* is performed in parallel and the result is calculated once all data is
* received.
* <p>
* This calculating generator does not listen to events from the data
* providers so it relies on the client to re-retrieve data as needed.
* </p>
*/
public class AsyncSumDataGenerator implements IDataGenerator {
/**
* DSF executor used to serialize data access within this data generator.
*/
final private DsfExecutor fExecutor;
/**
* Data generators to retrieve original data to perform calculations on.
*/
final private IDataGenerator[] fDataGenerators;
public AsyncSumDataGenerator(DsfExecutor executor, IDataGenerator[] generators) {
fExecutor = executor;
fDataGenerators = generators;
}
@Override
public void getCount(final DataRequestMonitor<Integer> rm) {
// Artificially delay the retrieval of the sum data to simulate
// real processing time.
fExecutor.schedule(new Runnable() {
@Override
public void run() {
doGetCount(rm);
}
}, PROCESSING_DELAY, TimeUnit.MILLISECONDS);
}
/**
* Performs the actual count retrieval and calculation.
* @param rm Request monitor to complete with data.
*/
private void doGetCount(final DataRequestMonitor<Integer> rm) {
// Array to store counts retrieved asynchronously
final int[] counts = new int[fDataGenerators.length];
// Counting request monitor is called once all data is retrieved.
final CountingRequestMonitor crm = new CountingRequestMonitor(fExecutor, rm) {
@Override
protected void handleSuccess() {
// Pick the highest count value.
Arrays.sort(counts, 0, counts.length - 1);
int maxCount = counts[counts.length - 1];
rm.setData(maxCount);
rm.done();
};
};
// Each call to data generator fills in one value in array.
for (int i = 0; i < fDataGenerators.length; i++) {
final int finalI = i;
fDataGenerators[i].getCount(new DataRequestMonitor<Integer>(ImmediateExecutor.getInstance(), crm) {
@Override
protected void handleSuccess() {
counts[finalI] = getData();
crm.done();
}
});
}
crm.setDoneCount(fDataGenerators.length);
}
@Override
public void getValue(final int index, final DataRequestMonitor<Integer> rm) {
// Artificially delay the retrieval of the sum data to simulate
// real processing time.
fExecutor.schedule(new Runnable() {
@Override
public void run() {
doGetValue(index, rm);
}
}, PROCESSING_DELAY, TimeUnit.MILLISECONDS);
}
/**
* Performs the actual value retrieval and calculation.
* @param rm Request monitor to complete with data.
*/
private void doGetValue(int index, final DataRequestMonitor<Integer> rm) {
// Array to store counts retrieved asynchronously
final int[] values = new int[fDataGenerators.length];
// Counting request monitor is called once all data is retrieved.
final CountingRequestMonitor crm = new CountingRequestMonitor(fExecutor, rm) {
@Override
protected void handleSuccess() {
// Sum up values in array.
int sum = 0;
for (int value : values) {
sum += value;
}
rm.setData(sum);
rm.done();
};
};
// Each call to data generator fills in one value in array.
for (int i = 0; i < fDataGenerators.length; i++) {
final int finalI = i;
fDataGenerators[i].getValue(index, new DataRequestMonitor<Integer>(ImmediateExecutor.getInstance(), crm) {
@Override
protected void handleSuccess() {
values[finalI] = getData();
crm.done();
}
});
}
crm.setDoneCount(fDataGenerators.length);
}
@Override
public void shutdown(RequestMonitor rm) {
rm.done();
}
@Override
public void addListener(final Listener listener) {
// no events generated
}
@Override
public void removeListener(Listener listener) {
// no events generated
}
}
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