| /** |
| * 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.xml; |
| |
| import javax.xml.parsers.DocumentBuilder; |
| import javax.xml.parsers.DocumentBuilderFactory; |
| import javax.xml.parsers.ParserConfigurationException; |
| |
| import org.w3c.dom.Document; |
| import org.xml.sax.InputSource; |
| |
| import com.datatorrent.api.Context; |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.common.util.BaseOperator; |
| import com.datatorrent.netlet.util.DTThrowable; |
| |
| /** |
| * This is the base implementation for an xml operator, |
| * which parses incoming tuples using the Java XML DOM parser. |
| * Subclasses must implement the methods which are use to process the parsed XML. |
| * <p></p> |
| * @displayName Abstract XML DOM |
| * @category XML |
| * @tags abstract, xml, dom |
| * |
| * @since 1.0.2 |
| */ |
| @org.apache.hadoop.classification.InterfaceStability.Evolving |
| public abstract class AbstractXmlDOMOperator<T> extends BaseOperator |
| { |
| protected transient DocumentBuilderFactory docFactory; |
| protected transient DocumentBuilder docBuilder; |
| |
| @Override |
| public void setup(Context.OperatorContext context) |
| { |
| try { |
| docFactory = DocumentBuilderFactory.newInstance(); |
| docBuilder = docFactory.newDocumentBuilder(); |
| } catch (ParserConfigurationException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| /** |
| * This port receives the tuples which will be parsed as xml. |
| */ |
| public transient DefaultInputPort<T> input = new DefaultInputPort<T>() |
| { |
| @Override |
| public void process(T tuple) |
| { |
| processTuple(tuple); |
| } |
| }; |
| |
| protected void processTuple(T tuple) |
| { |
| try { |
| InputSource source = getInputSource(tuple); |
| Document document = docBuilder.parse(source); |
| processDocument(document, tuple); |
| } catch (Exception e) { |
| DTThrowable.rethrow(e); |
| } |
| } |
| |
| protected abstract InputSource getInputSource(T tuple); |
| |
| protected abstract void processDocument(Document document, T tuple); |
| |
| } |