PublishEventMediatorFactory.java

/*
 * Copyright (c) 2014, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * 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.wso2.carbon.mediator.publishevent;

import org.apache.axiom.om.OMAttribute;
import org.apache.axiom.om.OMElement;
import org.apache.synapse.Mediator;
import org.apache.synapse.SynapseConstants;
import org.apache.synapse.SynapseException;
import org.apache.synapse.config.xml.AbstractMediatorFactory;
import org.apache.synapse.config.xml.SynapseXPathFactory;
import org.apache.synapse.config.xml.XMLConfigConstants;
import org.jaxen.JaxenException;

import javax.xml.namespace.QName;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

/**
 * Creates the publishEvent mediator with given configuration
 */
public class PublishEventMediatorFactory extends AbstractMediatorFactory {
	public static final QName PUBLISH_EVENT_QNAME = new QName(SynapseConstants.SYNAPSE_NAMESPACE, getTagName());
	public static final QName EVENT_SINK_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "eventSink");
	public static final QName STREAM_NAME_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "streamName");
	public static final QName STREAM_VERSION_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "streamVersion");
	public static final QName ATTRIBUTES_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "attributes");
	public static final QName ATTRIBUTE_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "attribute");
	public static final QName META_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "meta");
	public static final QName CORRELATION_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "correlation");
	public static final QName PAYLOAD_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "payload");
	public static final QName ARBITRARY_QNAME = new QName(XMLConfigConstants.SYNAPSE_NAMESPACE, "arbitrary");
	public static final QName TYPE_QNAME = new QName("type");
	public static final QName DEFAULT_QNAME = new QName("defaultValue");

	public static String getTagName() {
		return "publishEvent";
	}

	@Override
	public QName getTagQName() {
		return PUBLISH_EVENT_QNAME;
	}

	/**
	 * Creates a publishEvent mediator instance from given OMElement xml config
	 *
	 * @param omElement XML config of the mediator
	 * @param properties
	 * @return Created publishEvent mediator object
	 */
	@Override
	public Mediator createSpecificMediator(OMElement omElement, Properties properties) {
		PublishEventMediator mediator = new PublishEventMediator();

		OMElement streamName = omElement.getFirstChildWithName(STREAM_NAME_QNAME);
		if (streamName == null) {
			throw new SynapseException(STREAM_NAME_QNAME.getLocalPart() + " element missing");
		}
		mediator.setStreamName(streamName.getText());

		OMElement streamVersion = omElement.getFirstChildWithName(STREAM_VERSION_QNAME);
		if (streamVersion == null) {
			throw new SynapseException(STREAM_VERSION_QNAME.getLocalPart() + " element missing");
		}
		mediator.setStreamVersion(streamVersion.getText());

		OMElement attributes = omElement.getFirstChildWithName(ATTRIBUTES_QNAME);
		if (attributes != null) {
			OMElement meta = attributes.getFirstChildWithName(META_QNAME);
			if (meta != null) {
				Iterator<OMElement> iterator = meta.getChildrenWithName(ATTRIBUTE_QNAME);
				List<Property> propertyList = generatePropertyList(iterator);
				mediator.setMetaProperties(propertyList);
			}
			OMElement correlation = attributes.getFirstChildWithName(CORRELATION_QNAME);
			if (correlation != null) {
				Iterator<OMElement> iterator = correlation.getChildrenWithName(ATTRIBUTE_QNAME);
				List<Property> propertyList = generatePropertyList(iterator);
				mediator.setCorrelationProperties(propertyList);
			}
			OMElement payload = attributes.getFirstChildWithName(PAYLOAD_QNAME);
			if (payload != null) {
				Iterator<OMElement> iterator = payload.getChildrenWithName(ATTRIBUTE_QNAME);
				List<Property> propertyList = generatePropertyList(iterator);
				mediator.setPayloadProperties(propertyList);
			}
			OMElement arbitrary = attributes.getFirstChildWithName(ARBITRARY_QNAME);
			if (arbitrary != null) {
				Iterator<OMElement> iterator = arbitrary.getChildrenWithName(ATTRIBUTE_QNAME);
				List<Property> propertyList = generatePropertyList(iterator);

				for (Property property : propertyList) {
					if (!property.getType().equals(Property.DATA_TYPE_STRING)) {
						throw new SynapseException(
								"Invalid type " + property.getType() + " for arbitrary property " + property.getKey() +
								". Type of arbitrary attributes must be " +
								Property.DATA_TYPE_STRING);
					}
				}

				mediator.setArbitraryProperties(propertyList);
			}
		} else {
			throw new SynapseException(ATTRIBUTES_QNAME.getLocalPart() + " attribute missing");
		}

		OMElement eventSinkElement = omElement.getFirstChildWithName(EVENT_SINK_QNAME);
		if (eventSinkElement == null) {
			throw new SynapseException(EVENT_SINK_QNAME.getLocalPart() + " element missing");
		}
		mediator.setEventSinkName(eventSinkElement.getText());
		return mediator;
	}

	/**
	 * Creates a list of Property objects with XML elements pointed by provided iterator
	 *
	 * @param iterator OMElement iterator. (Each OMElement contains XML config for a Property object)
	 * @return Created Property list
	 */
	private List<Property> generatePropertyList(Iterator<OMElement> iterator) {
		List<Property> propertyList = new ArrayList<Property>();
		while (iterator.hasNext()) {
			OMElement element = iterator.next();
			OMAttribute nameAttr = element.getAttribute(ATT_NAME);
			if (nameAttr == null) {
				throw new SynapseException(ATT_NAME.getLocalPart() + " attribute missing in " + element.getLocalName());
			}
			OMAttribute typeAttr = element.getAttribute(TYPE_QNAME);
			if (typeAttr == null) {
				throw new SynapseException(
						TYPE_QNAME.getLocalPart() + " attribute missing in " + element.getLocalName());
			}
			OMAttribute valueAttr = element.getAttribute(ATT_VALUE);
			OMAttribute expressionAttr = element.getAttribute(ATT_EXPRN);
			if (valueAttr != null && expressionAttr != null) {
				throw new SynapseException(
						element.getLocalName() + " element can either have \"" + ATT_VALUE.getLocalPart() +
						"\" or \"" + ATT_EXPRN.getLocalPart() + "\" attribute but not both");
			}

			if (valueAttr == null && expressionAttr == null) {
				throw new SynapseException(
						element.getLocalName() + " element must have either \"" + ATT_VALUE.getLocalPart() +
						"\" or \"" + ATT_EXPRN.getLocalPart() + "\" attribute");
			}

			Property property = new Property();
			property.setKey(nameAttr.getAttributeValue());
			property.setType(typeAttr.getAttributeValue());
			if (valueAttr != null) {
				property.setValue(valueAttr.getAttributeValue());
			} else {
				try {
					property.setExpression(SynapseXPathFactory.getSynapseXPath(element, ATT_EXPRN));
				} catch (JaxenException e) {
					throw new SynapseException("Invalid expression attribute in " + element.getLocalName(), e);
				}
			}

			OMAttribute defaultAtr = element.getAttribute(DEFAULT_QNAME);
			if (defaultAtr != null) {
				property.setDefaultValue(defaultAtr.getAttributeValue());
			}

			propertyList.add(property);
		}
		return propertyList;
	}

	public static QName getNameAttributeQ() {
		return ATT_NAME;
	}

	public static QName getValueAttributeQ() {
		return ATT_VALUE;
	}

	public static QName getExpressionAttributeQ() {
		return ATT_EXPRN;
	}
}