001/*
002 * (C) Copyright 2006-2014 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.nuxeo.ecm.core.redis.retry;
017
018import org.apache.commons.logging.LogFactory;
019
020public class Retry {
021
022    public interface Block<T> {
023        T retry() throws FailException, ContinueException;
024    }
025
026    public interface Policy {
027        boolean allow();
028
029        void pause();
030    }
031
032    public static class ContinueException extends Exception {
033
034        private static final long serialVersionUID = 1L;
035
036        public ContinueException(Throwable cause) {
037            super(cause);
038        }
039
040    }
041
042    public static class FailException extends Exception {
043
044        public FailException(String message) {
045            super(message);
046        }
047
048        public FailException(Throwable cause) {
049            super(cause);
050        }
051
052        private static final long serialVersionUID = 1L;
053
054    }
055
056    public <T> T retry(Block<T> block, Policy policy) throws FailException {
057        FailException causes = new FailException(
058                "Cannot execute block, retry policy failed, check supressed exception for more infos");
059        while (policy.allow()) {
060            try {
061                return block.retry();
062            } catch (ContinueException error) {
063                causes.addSuppressed(error.getCause());
064            } catch (FailException error) {
065                causes.addSuppressed(error.getCause());
066                throw causes;
067            }
068            policy.pause();
069        }
070        throw causes;
071    }
072
073}