Java tutorial
/** * Copyright 2011-2015 John Ericksen * * Licensed 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.androidtransfuse.transaction; import com.google.common.collect.ImmutableSet; import java.util.HashMap; import java.util.Map; /** * @author John Ericksen */ public class TransactionProcessorChain implements TransactionProcessor<Void, Void> { private final TransactionProcessor beforeProcessor; private final TransactionProcessor afterProcessor; public TransactionProcessorChain(TransactionProcessor beforeProcessor, TransactionProcessor afterProcessor) { this.beforeProcessor = beforeProcessor; this.afterProcessor = afterProcessor; } @Override public void execute() { beforeProcessor.execute(); if (beforeProcessor.isComplete() && !afterProcessor.isComplete()) { afterProcessor.execute(); } } @Override public boolean isComplete() { return beforeProcessor.isComplete() && afterProcessor.isComplete(); } @Override public ImmutableSet<Exception> getErrors() { ImmutableSet.Builder<Exception> exceptions = ImmutableSet.builder(); exceptions.addAll(beforeProcessor.getErrors()); exceptions.addAll(afterProcessor.getErrors()); return exceptions.build(); } @Override public Map<Void, Void> getResults() { return new HashMap<Void, Void>(); } }