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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* 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.
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*
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package org.apache.http.examples.client;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.concurrent.FutureCallback;
import org.apache.http.impl.client.FutureRequestExecutionService;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpRequestFutureTask;
public class ClientWithRequestFuture {
public static void main(String[] args) throws Exception {
// the simplest way to create a HttpAsyncClientWithFuture
HttpClient httpclient = HttpClientBuilder.create()
.setMaxConnPerRoute(5)
.setMaxConnTotal(5).build();
ExecutorService execService = Executors.newFixedThreadPool(5);
FutureRequestExecutionService requestExecService = new FutureRequestExecutionService(
httpclient, execService);
try {
// Because things are asynchronous, you must provide a ResponseHandler
ResponseHandler<Boolean> handler = new ResponseHandler<Boolean>() {
public Boolean handleResponse(HttpResponse response) throws ClientProtocolException, IOException {
// simply return true if the status was OK
return response.getStatusLine().getStatusCode() == 200;
}
};
// Simple request ...
HttpGet request1 = new HttpGet("http://google.com");
HttpRequestFutureTask<Boolean> futureTask1 = requestExecService.execute(request1,
HttpClientContext.create(), handler);
Boolean wasItOk1 = futureTask1.get();
System.out.println("It was ok? " + wasItOk1);
// Cancel a request
try {
HttpGet request2 = new HttpGet("http://google.com");
HttpRequestFutureTask<Boolean> futureTask2 = requestExecService.execute(request2,
HttpClientContext.create(), handler);
futureTask2.cancel(true);
Boolean wasItOk2 = futureTask2.get();
System.out.println("It was cancelled so it should never print this: " + wasItOk2);
} catch (CancellationException e) {
System.out.println("We cancelled it, so this is expected");
}
// Request with a timeout
HttpGet request3 = new HttpGet("http://google.com");
HttpRequestFutureTask<Boolean> futureTask3 = requestExecService.execute(request3,
HttpClientContext.create(), handler);
Boolean wasItOk3 = futureTask3.get(10, TimeUnit.SECONDS);
System.out.println("It was ok? " + wasItOk3);
FutureCallback<Boolean> callback = new FutureCallback<Boolean>() {
public void completed(Boolean result) {
System.out.println("completed with " + result);
}
public void failed(Exception ex) {
System.out.println("failed with " + ex.getMessage());
}
public void cancelled() {
System.out.println("cancelled");
}
};
// Simple request with a callback
HttpGet request4 = new HttpGet("http://google.com");
// using a null HttpContext here since it is optional
// the callback will be called when the task completes, fails, or is cancelled
HttpRequestFutureTask<Boolean> futureTask4 = requestExecService.execute(request4,
HttpClientContext.create(), handler, callback);
Boolean wasItOk4 = futureTask4.get(10, TimeUnit.SECONDS);
System.out.println("It was ok? " + wasItOk4);
// Multiple requests, with a callback
HttpGet request5 = new HttpGet("http://google.com");
HttpGet request6 = new HttpGet("http://bing.com");
HttpGet request7 = new HttpGet("http://yahoo.com");
// using a null HttpContext here since it is optional
// the callback will be called for each request as their responses come back.
List<Future<Boolean>> futureTask = requestExecService.executeMultiple(
HttpClientContext.create(), handler, callback,
20,TimeUnit.SECONDS, request5, request6, request7);
// you can still access the futures directly, if you want. The futures are in the same order as the requests.
for (Future<Boolean> future : futureTask) {
System.out.println("another result " + future.get());
}
} finally {
requestExecService.close();
}
}
}