org.force66.insanity.RetryManager.java Source code

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Here is the source code for org.force66.insanity.RetryManager.java

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/*
 * This software is licensed under the Apache License, Version 2.0
 * (the "License") agreement; 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.force66.insanity;

import java.util.concurrent.Callable;

import org.apache.commons.lang3.Validate;

/**
 * Implementation of the Retry pattern.
 * @author D. Ashmore
 * @see RetryAlgorithm
 */
public class RetryManager<T> {

    private RetryAlgorithm retryAlgorithm;

    /**
     * @see DefaultRetryAlgorithm
     */
    public RetryManager() {
        this(new DefaultRetryAlgorithm());
    }

    public RetryManager(RetryAlgorithm algorithm) {
        Validate.notNull(algorithm, "Null algorithm not allowed.");
        retryAlgorithm = algorithm;

    }

    public T invoke(Callable<T> operation) {
        Validate.notNull(operation, "Null operation not allowed.");
        int nbrTries = 0;
        Exception lastFailure = null;
        retryAlgorithm.reset();

        while (retryAlgorithm.isExecutionAllowed()) {
            nbrTries++;
            try {
                T output = operation.call();
                return output;
            } catch (Exception e) {
                lastFailure = e;
                retryAlgorithm.reportExecutionFailure(e);
            }
        }

        throw new RetryException("invocation not successful.", lastFailure)
                .addContextValue("callable class", operation.getClass().getName())
                .addContextValue("callable", operation.toString()).addContextValue("nbrTries", nbrTries);
    }

    protected RetryAlgorithm getRetryAlgorithm() {
        return retryAlgorithm;
    }

}