001/**
002 * Copyright 2010-2014 The Kuali Foundation
003 *
004 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
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.kuali.common.util.runonce.smart;
017
018import org.kuali.common.util.execute.Executable;
019import org.kuali.common.util.log.LoggerUtils;
020import org.slf4j.Logger;
021
022import com.google.common.base.Preconditions;
023
024public class RunOnceExecutable implements Executable {
025
026        private static final Logger logger = LoggerUtils.make();
027
028        private final Executable executable;
029        private final RunOnce runOnce;
030        private final boolean skip;
031
032        @Override
033        public void execute() {
034
035                // Skip has been explicitly configured
036                if (skip) {
037                        logger.info("Skipping RunOnce");
038                        return;
039                }
040
041                // Give the RunOnce logic a chance to initialize itself
042                runOnce.initialize();
043
044                // If run once is not enabled, we are done
045                if (!runOnce.isTrue()) {
046                        return;
047                }
048
049                // Transition to INPROGRESS
050                runOnce.changeState(RunOnceState.INPROGRESS);
051
052                // Make sure the run once indicator no longer returns true
053                Preconditions.checkState(!runOnce.isTrue(), "Run once must be false");
054
055                try {
056                        // Now that we have transitioned things to INPROGRESS and verified that the RunOnce indicator
057                        // no longer returns true, it is safe to fire the executable
058                        // This sequence of events is what prevents us from running the executable more than once
059                        executable.execute();
060
061                        // Transition to COMPLETED
062                        runOnce.changeState(RunOnceState.COMPLETED);
063                } catch (Exception e) {
064                        // Transition to FAILED
065                        runOnce.changeState(RunOnceState.FAILED);
066                        throw new IllegalStateException("Unexpected execution error", e);
067                }
068        }
069
070        public static Builder builder(Executable executable, RunOnce runOnce) {
071                return new Builder(executable, runOnce);
072        }
073
074        public static class Builder {
075
076                // Required
077                private final Executable executable;
078                private final RunOnce runOnce;
079
080                // Optional
081                private boolean skip = false;
082
083                public Builder(Executable executable, RunOnce runOnce) {
084                        this.executable = executable;
085                        this.runOnce = runOnce;
086                }
087
088                public Builder skip(boolean skip) {
089                        this.skip = skip;
090                        return this;
091                }
092
093                public RunOnceExecutable build() {
094                        RunOnceExecutable instance = new RunOnceExecutable(this);
095                        validate(instance);
096                        return instance;
097                }
098
099                private void validate(RunOnceExecutable instance) {
100                        Preconditions.checkNotNull(instance.getExecutable(), "executable cannot be null");
101                        Preconditions.checkNotNull(instance.getRunOnce(), "runOnce cannot be null");
102                }
103        }
104
105        private RunOnceExecutable(Builder builder) {
106                this.executable = builder.executable;
107                this.runOnce = builder.runOnce;
108                this.skip = builder.skip;
109        }
110
111        public Executable getExecutable() {
112                return executable;
113        }
114
115        public boolean isSkip() {
116                return skip;
117        }
118
119        public RunOnce getRunOnce() {
120                return runOnce;
121        }
122
123}