| /* |
| * 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.beam.runners.core.triggers; |
| |
| import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument; |
| |
| import java.util.Arrays; |
| import java.util.List; |
| import org.apache.beam.sdk.annotations.Experimental; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Joiner; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableList; |
| |
| /** |
| * Create a composite {@link TriggerStateMachine} that fires once after at least one of its |
| * sub-triggers have fired. |
| */ |
| @Experimental(Experimental.Kind.TRIGGER) |
| public class AfterFirstStateMachine extends TriggerStateMachine { |
| |
| AfterFirstStateMachine(List<TriggerStateMachine> subTriggers) { |
| super(subTriggers); |
| checkArgument(subTriggers.size() > 1); |
| } |
| |
| /** Returns an {@code AfterFirst} {@code Trigger} with the given subtriggers. */ |
| @SafeVarargs |
| public static TriggerStateMachine of(TriggerStateMachine... triggers) { |
| return new AfterFirstStateMachine(Arrays.asList(triggers)); |
| } |
| |
| public static TriggerStateMachine of(Iterable<? extends TriggerStateMachine> triggers) { |
| return new AfterFirstStateMachine(ImmutableList.copyOf(triggers)); |
| } |
| |
| @Override |
| public void onElement(OnElementContext c) throws Exception { |
| for (ExecutableTriggerStateMachine subTrigger : c.trigger().subTriggers()) { |
| subTrigger.invokeOnElement(c); |
| } |
| } |
| |
| @Override |
| public void onMerge(OnMergeContext c) throws Exception { |
| for (ExecutableTriggerStateMachine subTrigger : c.trigger().subTriggers()) { |
| subTrigger.invokeOnMerge(c); |
| } |
| updateFinishedStatus(c); |
| } |
| |
| @Override |
| public boolean shouldFire(TriggerStateMachine.TriggerContext context) throws Exception { |
| for (ExecutableTriggerStateMachine subtrigger : context.trigger().subTriggers()) { |
| if (context.forTrigger(subtrigger).trigger().isFinished() |
| || subtrigger.invokeShouldFire(context)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public void onFire(TriggerContext context) throws Exception { |
| for (ExecutableTriggerStateMachine subTrigger : context.trigger().subTriggers()) { |
| TriggerContext subContext = context.forTrigger(subTrigger); |
| if (subTrigger.invokeShouldFire(subContext)) { |
| // If the trigger is ready to fire, then do whatever it needs to do. |
| subTrigger.invokeOnFire(subContext); |
| } else { |
| // If the trigger is not ready to fire, it is nonetheless true that whatever |
| // pending pane it was tracking is now gone. |
| subTrigger.invokeClear(subContext); |
| } |
| } |
| context.trigger().setFinished(true); |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder builder = new StringBuilder("AfterFirst.of("); |
| Joiner.on(", ").appendTo(builder, subTriggers); |
| builder.append(")"); |
| |
| return builder.toString(); |
| } |
| |
| private void updateFinishedStatus(TriggerContext c) { |
| boolean anyFinished = false; |
| for (ExecutableTriggerStateMachine subTrigger : c.trigger().subTriggers()) { |
| anyFinished |= c.forTrigger(subTrigger).trigger().isFinished(); |
| } |
| c.trigger().setFinished(anyFinished); |
| } |
| } |