Java tutorial
/* * 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.samza.translation; import com.google.common.collect.Iterables; import java.util.Map; import org.apache.beam.runners.samza.SamzaPipelineOptions; import org.apache.beam.sdk.runners.AppliedPTransform; import org.apache.beam.sdk.runners.TransformHierarchy; import org.apache.beam.sdk.transforms.PTransform; import org.apache.beam.sdk.values.PValue; /** Helper that provides context data such as output for config generation. */ public class ConfigContext { private final Map<PValue, String> idMap; private AppliedPTransform<?, ?, ?> currentTransform; private final SamzaPipelineOptions options; public ConfigContext(Map<PValue, String> idMap, SamzaPipelineOptions options) { this.idMap = idMap; this.options = options; } public void setCurrentTransform(AppliedPTransform<?, ?, ?> currentTransform) { this.currentTransform = currentTransform; } public void clearCurrentTransform() { this.currentTransform = null; } @SuppressWarnings("unchecked") public <OutT extends PValue> OutT getOutput(PTransform<?, OutT> transform) { return (OutT) Iterables.getOnlyElement(this.currentTransform.getOutputs().values()); } public String getOutputId(TransformHierarchy.Node node) { return getIdForPValue(Iterables.getOnlyElement(node.getOutputs().values())); } public SamzaPipelineOptions getPipelineOptions() { return this.options; } private String getIdForPValue(PValue pvalue) { final String id = idMap.get(pvalue); if (id == null) { throw new IllegalArgumentException("No id mapping for value: " + pvalue); } return id; } }