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Java example source code file (DefaultHttpRequestRetryHandler.java)

This example source code file (DefaultHttpRequestRetryHandler.java) 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 tags/keywords

boolean, connectexception, defaulthttprequestretryhandler, httpcontext, httpentityenclosingrequest, httprequest, illegalargumentexception, immutable, interruptedioexception, io, ioexception, net, network, nohttpresponseexception, ssl, sslhandshakeexception, unknownhostexception

The DefaultHttpRequestRetryHandler.java example source code

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * 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
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.impl.client;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.ConnectException;
import java.net.UnknownHostException;

import javax.net.ssl.SSLHandshakeException;

import org.apache.http.annotation.Immutable;

import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpRequest;
import org.apache.http.NoHttpResponseException;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.ExecutionContext;

/**
 * The default {@link HttpRequestRetryHandler} used by request executors.
 * 
 *
 * @since 4.0
 */
@Immutable
public class DefaultHttpRequestRetryHandler implements HttpRequestRetryHandler {

    /** the number of times a method will be retried */
    private final int retryCount;
    
    /** Whether or not methods that have successfully sent their request will be retried */
    private final boolean requestSentRetryEnabled;
    
    /**
     * Default constructor
     */
    public DefaultHttpRequestRetryHandler(int retryCount, boolean requestSentRetryEnabled) {
        super();
        this.retryCount = retryCount;
        this.requestSentRetryEnabled = requestSentRetryEnabled;
    }
    
    /**
     * Default constructor
     */
    public DefaultHttpRequestRetryHandler() {
        this(3, false);
    }
    /** 
     * Used <code>retryCount and requestSentRetryEnabled to determine
     * if the given method should be retried.
     */
    public boolean retryRequest(
            final IOException exception, 
            int executionCount,
            final HttpContext context) {
        if (exception == null) {
            throw new IllegalArgumentException("Exception parameter may not be null");
        }
        if (context == null) {
            throw new IllegalArgumentException("HTTP context may not be null");
        }
        if (executionCount > this.retryCount) {
            // Do not retry if over max retry count
            return false;
        }
        if (exception instanceof NoHttpResponseException) {
            // Retry if the server dropped connection on us
            return true;
        }
        if (exception instanceof InterruptedIOException) {
            // Timeout
            return false;
        }
        if (exception instanceof UnknownHostException) {
            // Unknown host
            return false;
        }
        if (exception instanceof ConnectException) {
            // Connection refused 
            return false;
        }
        if (exception instanceof SSLHandshakeException) {
            // SSL handshake exception
            return false;
        }
        
        HttpRequest request = (HttpRequest)
            context.getAttribute(ExecutionContext.HTTP_REQUEST);
        boolean idempotent = !(request instanceof HttpEntityEnclosingRequest); 
        if (idempotent) {
            // Retry if the request is considered idempotent 
            return true;
        }
        
        Boolean b = (Boolean)
            context.getAttribute(ExecutionContext.HTTP_REQ_SENT);
        boolean sent = (b != null && b.booleanValue());
        
        if (!sent || this.requestSentRetryEnabled) {
            // Retry if the request has not been sent fully or
            // if it's OK to retry methods that have been sent
            return true;
        }
        // otherwise do not retry
        return false;
    }
    
    /**
     * @return <code>true if this handler will retry methods that have 
     * successfully sent their request, <code>false otherwise
     */
    public boolean isRequestSentRetryEnabled() {
        return requestSentRetryEnabled;
    }

    /**
     * @return the maximum number of times a method will be retried
     */
    public int getRetryCount() {
        return retryCount;
    }
}

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