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.apex.malhar.lib.join; import java.lang.reflect.Array; import java.util.HashMap; import java.util.Map; import org.apache.commons.lang3.ClassUtils; import com.datatorrent.api.Context; import com.datatorrent.api.DefaultInputPort; import com.datatorrent.api.DefaultOutputPort; import com.datatorrent.api.Operator; import com.datatorrent.api.StreamCodec; import com.datatorrent.api.annotation.InputPortFieldAnnotation; import com.datatorrent.api.annotation.OutputPortFieldAnnotation; import com.datatorrent.lib.util.PojoUtils; /** * Concrete implementation of AbstractManagedStateInnerJoinOperator and receives objects from both streams. * * @displayName POJO Inner Join Operator * @tags join * * @since 3.5.0 */ @org.apache.hadoop.classification.InterfaceStability.Evolving public class POJOInnerJoinOperator extends AbstractManagedStateInnerJoinOperator<Object, Object> implements Operator.ActivationListener<Context> { private transient long timeIncrement; private transient FieldObjectMap[] inputFieldObjects = (FieldObjectMap[]) Array .newInstance(FieldObjectMap.class, 2); protected transient Class<?> outputClass; private long time = System.currentTimeMillis(); @OutputPortFieldAnnotation(schemaRequired = true) public final transient DefaultOutputPort<Object> outputPort = new DefaultOutputPort<Object>() { @Override public void setup(Context.PortContext context) { outputClass = context.getValue(Context.PortContext.TUPLE_CLASS); } }; @InputPortFieldAnnotation(schemaRequired = true) public transient DefaultInputPort<Object> input1 = new DefaultInputPort<Object>() { @Override public void setup(Context.PortContext context) { inputFieldObjects[0].inputClass = context.getValue(Context.PortContext.TUPLE_CLASS); } @Override public void process(Object tuple) { processTuple(tuple, true); } @Override public StreamCodec<Object> getStreamCodec() { return getInnerJoinStreamCodec(true); } }; @InputPortFieldAnnotation(schemaRequired = true) public transient DefaultInputPort<Object> input2 = new DefaultInputPort<Object>() { @Override public void setup(Context.PortContext context) { inputFieldObjects[1].inputClass = context.getValue(Context.PortContext.TUPLE_CLASS); } @Override public void process(Object tuple) { processTuple(tuple, false); } @Override public StreamCodec<Object> getStreamCodec() { return getInnerJoinStreamCodec(false); } }; @Override public void setup(Context.OperatorContext context) { timeIncrement = context.getValue(Context.OperatorContext.APPLICATION_WINDOW_COUNT) * context.getValue(Context.DAGContext.STREAMING_WINDOW_SIZE_MILLIS); super.setup(context); for (int i = 0; i < 2; i++) { inputFieldObjects[i] = new FieldObjectMap(); } } /** * Extract the time value from the given tuple * @param tuple given tuple * @param isStream1Data Specifies whether the given tuple belongs to stream1 or not. * @return the time in milliseconds */ @Override public long extractTime(Object tuple, boolean isStream1Data) { return timeFields == null ? time : (long) (isStream1Data ? inputFieldObjects[0].timeFieldGet.get(tuple) : inputFieldObjects[1].timeFieldGet.get(tuple)); } /** * Create getters for the key and time fields and setters for the include fields. */ private void generateSettersAndGetters() { for (int i = 0; i < 2; i++) { Class inputClass = inputFieldObjects[i].inputClass; try { inputFieldObjects[i].keyGet = PojoUtils.createGetter(inputClass, keyFieldExpressions.get(i), Object.class); if (timeFields != null && timeFields.size() == 2) { Class timeField = ClassUtils .primitiveToWrapper(inputClass.getDeclaredField(timeFields.get(i)).getType()); inputFieldObjects[i].timeFieldGet = PojoUtils.createGetter(inputClass, timeFields.get(i), timeField); } for (int j = 0; j < includeFields[i].length; j++) { Class inputField = ClassUtils .primitiveToWrapper(inputClass.getDeclaredField(includeFields[i][j]).getType()); Class outputField = ClassUtils .primitiveToWrapper(outputClass.getDeclaredField(includeFields[i][j]).getType()); if (inputField != outputField) { continue; } inputFieldObjects[i].fieldMap.put( PojoUtils.createGetter(inputClass, includeFields[i][j], inputField), PojoUtils.createSetter(outputClass, includeFields[i][j], outputField)); } } catch (NoSuchFieldException e) { throw new RuntimeException(e); } } } /** * Extract the key value from the given tuple * @param tuple given tuple * @param isStream1Data Specifies whether the given tuple belongs to stream1 or not. * @return the key object */ @Override public Object extractKey(Object tuple, boolean isStream1Data) { return isStream1Data ? inputFieldObjects[0].keyGet.get(tuple) : inputFieldObjects[1].keyGet.get(tuple); } /** * Merge the given tuples * @param tuple1 tuple belongs to stream1 * @param tuple2 tuple belongs to stream1 * @return the merged output object */ @Override public Object mergeTuples(Object tuple1, Object tuple2) { Object o; try { o = outputClass.newInstance(); for (Map.Entry<PojoUtils.Getter, PojoUtils.Setter> g : inputFieldObjects[0].fieldMap.entrySet()) { g.getValue().set(o, g.getKey().get(tuple1)); } for (Map.Entry<PojoUtils.Getter, PojoUtils.Setter> g : inputFieldObjects[1].fieldMap.entrySet()) { g.getValue().set(o, g.getKey().get(tuple2)); } } catch (InstantiationException | IllegalAccessException e) { throw new RuntimeException(e); } return o; } /** * Emit the given tuple through the outputPort * @param tuple given tuple */ @Override public void emitTuple(Object tuple) { outputPort.emit(tuple); } @Override public void activate(Context context) { generateSettersAndGetters(); } @Override public void deactivate() { } @Override public void endWindow() { super.endWindow(); time += timeIncrement; } /** * Returns the streamcodec for the streams * @param isStream1data Specifies whether the codec needs for stream1 or stream2. * @return the object of JoinStreamCodec */ private StreamCodec<Object> getInnerJoinStreamCodec(boolean isStream1data) { if (isStream1data) { return new JoinStreamCodec(getLeftKeyExpression()); } return new JoinStreamCodec(getRightKeyExpression()); } private class FieldObjectMap { public Class<?> inputClass; public PojoUtils.Getter keyGet; public PojoUtils.Getter timeFieldGet; public Map<PojoUtils.Getter, PojoUtils.Setter> fieldMap; public FieldObjectMap() { fieldMap = new HashMap<>(); } } }