Java tutorial
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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.http2.impl.client; import java.io.IOException; import java.io.InterruptedIOException; import java.net.URI; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http2.HttpHost; import org.apache.http2.HttpRequest; import org.apache.http2.HttpResponse; import org.apache.http2.annotation.ThreadSafe; import org.apache.http2.client.HttpClient; import org.apache.http2.client.ResponseHandler; import org.apache.http2.client.ServiceUnavailableRetryStrategy; import org.apache.http2.client.methods.HttpUriRequest; import org.apache.http2.conn.ClientConnectionManager; import org.apache.http2.params.HttpParams; import org.apache.http2.protocol.HttpContext; import org.apache.http2.util.EntityUtils; /** * {@link HttpClient} implementation that can automatically retry the request in case of * a non-2xx response using the {@link ServiceUnavailableRetryStrategy} interface. * * @since 4.2 */ @ThreadSafe public class AutoRetryHttpClient implements HttpClient { private final HttpClient backend; private final ServiceUnavailableRetryStrategy retryStrategy; private final Log log = LogFactory.getLog(getClass()); public AutoRetryHttpClient(final HttpClient client, final ServiceUnavailableRetryStrategy retryStrategy) { super(); if (client == null) { throw new IllegalArgumentException("HttpClient may not be null"); } if (retryStrategy == null) { throw new IllegalArgumentException("ServiceUnavailableRetryStrategy may not be null"); } this.backend = client; this.retryStrategy = retryStrategy; } /** * Constructs a {@code AutoRetryHttpClient} with default caching settings that * stores cache entries in memory and uses a vanilla * {@link DefaultHttpClient} for backend requests. */ public AutoRetryHttpClient() { this(new DefaultHttpClient(), new DefaultServiceUnavailableRetryStrategy()); } /** * Constructs a {@code AutoRetryHttpClient} with the given caching options that * stores cache entries in memory and uses a vanilla * {@link DefaultHttpClient} for backend requests. * * @param config * retry configuration module options */ public AutoRetryHttpClient(ServiceUnavailableRetryStrategy config) { this(new DefaultHttpClient(), config); } /** * Constructs a {@code AutoRetryHttpClient} with default caching settings that * stores cache entries in memory and uses the given {@link HttpClient} for * backend requests. * * @param client * used to make origin requests */ public AutoRetryHttpClient(HttpClient client) { this(client, new DefaultServiceUnavailableRetryStrategy()); } public HttpResponse execute(HttpHost target, HttpRequest request) throws IOException { HttpContext defaultContext = null; return execute(target, request, defaultContext); } public <T> T execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler) throws IOException { return execute(target, request, responseHandler, null); } public <T> T execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context) throws IOException { HttpResponse resp = execute(target, request, context); return responseHandler.handleResponse(resp); } public HttpResponse execute(HttpUriRequest request) throws IOException { HttpContext context = null; return execute(request, context); } public HttpResponse execute(HttpUriRequest request, HttpContext context) throws IOException { URI uri = request.getURI(); HttpHost httpHost = new HttpHost(uri.getHost(), uri.getPort(), uri.getScheme()); return execute(httpHost, request, context); } public <T> T execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler) throws IOException { return execute(request, responseHandler, null); } public <T> T execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context) throws IOException { HttpResponse resp = execute(request, context); return responseHandler.handleResponse(resp); } public HttpResponse execute(HttpHost target, HttpRequest request, HttpContext context) throws IOException { for (int c = 1;; c++) { HttpResponse response = backend.execute(target, request, context); try { if (retryStrategy.retryRequest(response, c, context)) { EntityUtils.consume(response.getEntity()); long nextInterval = retryStrategy.getRetryInterval(); try { log.trace("Wait for " + nextInterval); Thread.sleep(nextInterval); } catch (InterruptedException e) { throw new InterruptedIOException(e.getMessage()); } } else { return response; } } catch (RuntimeException ex) { try { EntityUtils.consume(response.getEntity()); } catch (IOException ioex) { log.warn("I/O error consuming response content", ioex); } throw ex; } } } public ClientConnectionManager getConnectionManager() { return backend.getConnectionManager(); } public HttpParams getParams() { return backend.getParams(); } }