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 * 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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 * KIND, either express or implied.  See the License for the
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package org.apache.http.impl.client;

import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.http.HttpRequest;
import org.apache.http.annotation.Contract;
import org.apache.http.annotation.ThreadingBehavior;

HttpRequestRetryHandler which assumes that all requested HTTP methods which should be idempotent according to RFC-2616 are in fact idempotent and can be retried. 

According to RFC-2616 section 9.1.2 the idempotent HTTP methods are:
GET, HEAD, PUT, DELETE, OPTIONS, and TRACE

Since:
4.2/**
 * {@link org.apache.http.client.HttpRequestRetryHandler} which assumes
 * that all requested HTTP methods which should be idempotent according
 * to RFC-2616 are in fact idempotent and can be retried.
 * <p>
 * According to RFC-2616 section 9.1.2 the idempotent HTTP methods are:
 * GET, HEAD, PUT, DELETE, OPTIONS, and TRACE
 * </p>
 *
 * @since 4.2
 */
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class StandardHttpRequestRetryHandler extends DefaultHttpRequestRetryHandler {

    private final Map<String, Boolean> idempotentMethods;

    
Default constructor
/**
     * Default constructor
     */
    public StandardHttpRequestRetryHandler(final int retryCount, final boolean requestSentRetryEnabled) {
        super(retryCount, requestSentRetryEnabled);
        this.idempotentMethods = new ConcurrentHashMap<String, Boolean>();
        this.idempotentMethods.put("GET", Boolean.TRUE);
        this.idempotentMethods.put("HEAD", Boolean.TRUE);
        this.idempotentMethods.put("PUT", Boolean.TRUE);
        this.idempotentMethods.put("DELETE", Boolean.TRUE);
        this.idempotentMethods.put("OPTIONS", Boolean.TRUE);
        this.idempotentMethods.put("TRACE", Boolean.TRUE);
    }

    
Default constructor
/**
     * Default constructor
     */
    public StandardHttpRequestRetryHandler() {
        this(3, false);
    }

    @Override
    protected boolean handleAsIdempotent(final HttpRequest request) {
        final String method = request.getRequestLine().getMethod().toUpperCase(Locale.ROOT);
        final Boolean b = this.idempotentMethods.get(method);
        return b != null && b.booleanValue();
    }

}