WBE22TextMessageHandler.java

/*******************************************************************************
 * Copyright (C) 2013, 2014, International Business Machines Corporation
 * All Rights Reserved
 *******************************************************************************/
package com.ibm.streamsx.messaging.jms;

import java.util.List;

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import com.ibm.streams.operator.Tuple;
import com.ibm.streams.operator.metrics.Metric;

//This class handles the wbe22 message type 
class WBE22TextMessageHandler extends BaseXMLMessageHandler {
	
	// the document builder
	private DocumentBuilder documentBuilder;

	// constructor
	public WBE22TextMessageHandler(List<NativeSchema> nativeSchemaObjects,
			String eventName) throws TransformerConfigurationException,
			ParserConfigurationException {
		// call the base class constructor to initialize the native schema
		// attributes and event name

		super(nativeSchemaObjects, eventName);

		documentBuilder = DocumentBuilderFactory.newInstance()
				.newDocumentBuilder();
	}

	// constructor
	public WBE22TextMessageHandler(List<NativeSchema> nativeSchemaObjects,
			String eventName, Metric nTruncatedInserts)
			throws TransformerConfigurationException,
			ParserConfigurationException {
		// call the base class constructor to initialize the native schema
		// attributes,nTruncatedInserts and event name

		super(nativeSchemaObjects, eventName, nTruncatedInserts);
		documentBuilder = DocumentBuilderFactory.newInstance()
				.newDocumentBuilder();
	}

	// For JMSSink operator, convert the incoming tuple to a JMS TextMessage
	public Message convertTupleToMessage(Tuple tuple, Session session)
			throws JMSException, ParserConfigurationException,
			TransformerException {
		// create a new TextMessage
		TextMessage message;
		synchronized (session) {
			message = (TextMessage) session.createTextMessage();
		}
		// create document element
		Document document;
		synchronized (documentBuilder) {
			document = documentBuilder.newDocument();
		}
		// create elements for constructing the xml document
		// with wbe22 mesage format
		Element field;
		// creates an element for root tuple
		Element rootElement = document.createElement("connector");	//$NON-NLS-1$ 
		rootElement.setAttribute("name", "System S"); //$NON-NLS-1$ //$NON-NLS-2$
		rootElement.setAttribute("version", "2.2"); //$NON-NLS-1$ //$NON-NLS-2$
		Element rootEle1 = document.createElement("connector-object"); //$NON-NLS-1$
		rootEle1.setAttribute("name", eventName); //$NON-NLS-1$
		rootElement.appendChild(rootEle1);
		String stringdata = new String();
		// variable to specify if any of the attributes in the message is
		// truncated
		boolean isTruncated = false;

		for (NativeSchema currentObject : nativeSchemaObjects) {
			// iterate through the native schema elements
			// extract the name, type and length

			final String name = currentObject.getName();
			final int length = currentObject.getLength();
			field = document.createElement("field"); // create another element //$NON-NLS-1$
			field.setAttribute("name", name); //$NON-NLS-1$
			// handle based on data type
			switch (tuple.getStreamSchema().getAttribute(name).getType()
					.getMetaType()) {
			// BLOB is not supported for wbe22 message class
			case RSTRING:
			case USTRING:
				// extract the String
				// get its length
				String rdata = tuple.getString(name);
				int size = rdata.length();
				// If no length was specified in native schema or
				// if the length of the String rdata is less than the length
				// specified in native schema
				if (length == LENGTH_ABSENT_IN_NATIVE_SCHEMA || size <= length) {
					stringdata = rdata;
				}
				// if the length of rdate is greater than the length specified
				// in native schema
				// set the isTruncated to true
				// truncate the String
				else if (size > length) {
					isTruncated = true;
					stringdata = rdata.substring(0, length);
				}
				break;
			// spl types decimal32, decimal64,decimal128, timestamp are mapped
			// to String.
			case TIMESTAMP:
				stringdata = (tuple.getTimestamp(name).getTimeAsSeconds())
						.toString();
				break;

			case DECIMAL32:
			case DECIMAL64:
			case DECIMAL128:

				// for decimal
				stringdata = tuple.getBigDecimal(name).toString();
				break;
			default:
				stringdata = tuple.getString(name);
				break;
			}

			field.appendChild(document.createTextNode(stringdata));
			// append to root element
			rootEle1.appendChild(field);
		}
		// append rootElement to the document
		document.appendChild(rootElement);
		// set the message
		message.setText(createFinalDocument(document));
		// if the isTruncated boolean is set, increment the metric
		// nTruncatedInserts
		if (isTruncated) {
			nTruncatedInserts.incrementValue(1);
		}
		// return the message
		return message;
	}

}