wayang-platforms/wayang-java/src/main/java/org/apache/wayang/java/execution/JavaExecutionContext.java

/*
 * 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.wayang.java.execution;

import java.util.Collection;
import org.apache.wayang.core.api.exception.WayangException;
import org.apache.wayang.core.function.ExecutionContext;
import org.apache.wayang.core.plan.wayangplan.InputSlot;
import org.apache.wayang.core.platform.ChannelInstance;
import org.apache.wayang.java.channels.CollectionChannel;
import org.apache.wayang.java.operators.JavaExecutionOperator;
import org.apache.wayang.java.platform.JavaPlatform;

/**
 * {@link ExecutionContext} implementation for the {@link JavaPlatform}.
 */
public class JavaExecutionContext implements ExecutionContext {

    private final JavaExecutionOperator operator;

    private final ChannelInstance[] inputs;

    private final int iterationNumber;

    public JavaExecutionContext(JavaExecutionOperator operator, ChannelInstance[] inputs, int iterationNumber) {
        this.operator = operator;
        this.inputs = inputs;
        this.iterationNumber = iterationNumber;
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> Collection<T> getBroadcast(String name) {
        for (int i = 0; i < this.operator.getNumInputs(); i++) {
            final InputSlot<?> input = this.operator.getInput(i);
            if (input.isBroadcast() && input.getName().equals(name)) {
                final CollectionChannel.Instance broadcastChannelInstance = (CollectionChannel.Instance) this.inputs[i];
                return (Collection<T>) broadcastChannelInstance.provideCollection();
            }
        }

        throw new WayangException("No such broadcast found: " + name);
    }

    @Override
    public int getCurrentIteration() {
        return this.iterationNumber;
    }
}