| /** |
| * 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.appdata.snapshot; |
| |
| import java.util.Map; |
| |
| import javax.validation.constraints.NotNull; |
| |
| import org.apache.apex.malhar.lib.appdata.gpo.GPOGetters; |
| import org.apache.apex.malhar.lib.appdata.gpo.GPOMutable; |
| import org.apache.apex.malhar.lib.appdata.gpo.GPOUtils; |
| import org.apache.hadoop.classification.InterfaceStability.Evolving; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * This operator accepts a list of POJOs, and serves the data under the {@link SnapshotSchema}. |
| * Each POJO represents a row in the table, and the full list of POJOs represents a table. |
| * @displayName App Data Snapshot POJO Server |
| * @category DT View Integration |
| * @tags app data, snapshot, pojo |
| * @since 3.0.0 |
| */ |
| @Evolving |
| public class AppDataSnapshotServerPOJO extends AbstractAppDataSnapshotServer<Object> |
| { |
| /** |
| * Flag indicating whether or not the first tuple was processed. |
| */ |
| private boolean firstTupleProcessed = false; |
| |
| @NotNull |
| private Map<String, String> fieldToGetter; |
| /** |
| * The getters for retrieving values from input POJOs. |
| */ |
| private GPOGetters getters; |
| |
| /** |
| * Create the operator. |
| */ |
| public AppDataSnapshotServerPOJO() |
| { |
| //Do nothing |
| } |
| |
| @Override |
| public GPOMutable convert(Object inputEvent) |
| { |
| firstTuple(inputEvent); |
| |
| GPOMutable convertedResult = new GPOMutable(schema.getValuesDescriptor()); |
| |
| GPOUtils.copyPOJOToGPO(convertedResult, getters, inputEvent); |
| return convertedResult; |
| } |
| |
| /** |
| * A helper method which builds the getter methods for retrieving fields from pojos. |
| * @param inputEvent An input POJO. |
| */ |
| private void firstTuple(Object inputEvent) |
| { |
| if (firstTupleProcessed) { |
| return; |
| } |
| |
| firstTupleProcessed = true; |
| |
| Class<?> clazz = inputEvent.getClass(); |
| |
| getters = GPOUtils.buildGPOGetters(fieldToGetter, |
| schema.getValuesDescriptor(), |
| clazz); |
| } |
| |
| /** |
| * This sets the fieldToGetter map. The fieldToGetter map defines how to retrieve a field specified |
| * in the schema from an input POJO. |
| * @param fieldToGetter The map from a field in the schema to its corresponding getter. |
| */ |
| public void setFieldToGetter(@NotNull Map<String, String> fieldToGetter) |
| { |
| this.fieldToGetter = Preconditions.checkNotNull(fieldToGetter); |
| } |
| |
| /** |
| * This gets the fieldToGetter map. |
| * @return The fieldToGetter map. |
| */ |
| public Map<String, String> getFieldToGetter() |
| { |
| return fieldToGetter; |
| } |
| } |