org.apache.hadoop.io.retry.RetryProxy.java Source code

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Here is the source code for org.apache.hadoop.io.retry.RetryProxy.java

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/*
 * 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.
 */
package org.apache.hadoop.io.retry;

import java.lang.reflect.Proxy;
import java.util.Map;

/**
 * <p>
 * A factory for creating retry proxies.
 * </p>
 */
public class RetryProxy {
    /**
     * <p>
     * Create a proxy for an interface of an implementation class
     * using the same retry policy for each method in the interface. 
     * </p>
     * @param iface the interface that the retry will implement
     * @param implementation the instance whose methods should be retried
     * @param retryPolicy the policy for retrying method call failures
     * @return the retry proxy
     */
    public static <T> Object create(Class<T> iface, T implementation, RetryPolicy retryPolicy) {
        return RetryProxy.create(iface, new DefaultFailoverProxyProvider<T>(iface, implementation), retryPolicy);
    }

    /**
     * Create a proxy for an interface of implementations of that interface using
     * the given {@link FailoverProxyProvider} and the same retry policy for each
     * method in the interface.
     * 
     * @param iface the interface that the retry will implement
     * @param proxyProvider provides implementation instances whose methods should be retried
     * @param retryPolicy the policy for retrying or failing over method call failures
     * @return the retry proxy
     */
    public static <T> Object create(Class<T> iface, FailoverProxyProvider<T> proxyProvider,
            RetryPolicy retryPolicy) {
        return Proxy.newProxyInstance(proxyProvider.getInterface().getClassLoader(), new Class<?>[] { iface },
                new RetryInvocationHandler<T>(proxyProvider, retryPolicy));
    }

    /**
     * Create a proxy for an interface of an implementation class
     * using the a set of retry policies specified by method name.
     * If no retry policy is defined for a method then a default of
     * {@link RetryPolicies#TRY_ONCE_THEN_FAIL} is used.
     * 
     * @param iface the interface that the retry will implement
     * @param implementation the instance whose methods should be retried
     * @param methodNameToPolicyMap a map of method names to retry policies
     * @return the retry proxy
     */
    public static <T> Object create(Class<T> iface, T implementation,
            Map<String, RetryPolicy> methodNameToPolicyMap) {
        return create(iface, new DefaultFailoverProxyProvider<T>(iface, implementation), methodNameToPolicyMap,
                RetryPolicies.TRY_ONCE_THEN_FAIL);
    }

    /**
     * Create a proxy for an interface of implementations of that interface using
     * the given {@link FailoverProxyProvider} and the a set of retry policies
     * specified by method name. If no retry policy is defined for a method then a
     * default of {@link RetryPolicies#TRY_ONCE_THEN_FAIL} is used.
     * 
     * @param iface the interface that the retry will implement
     * @param proxyProvider provides implementation instances whose methods should be retried
     * @param methodNameToPolicyMapa map of method names to retry policies
     * @return the retry proxy
     */
    public static <T> Object create(Class<T> iface, FailoverProxyProvider<T> proxyProvider,
            Map<String, RetryPolicy> methodNameToPolicyMap, RetryPolicy defaultPolicy) {
        return Proxy.newProxyInstance(proxyProvider.getInterface().getClassLoader(), new Class<?>[] { iface },
                new RetryInvocationHandler<T>(proxyProvider, defaultPolicy, methodNameToPolicyMap));
    }
}