/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.event.xml;
import com.espertech.esper.client.ConfigurationEventTypeXMLDOM;
import com.espertech.esper.client.EPException;
import com.espertech.esper.client.EventPropertyGetter;
import com.espertech.esper.client.FragmentEventType;
import com.espertech.esper.event.EventAdapterService;
import com.espertech.esper.event.EventTypeMetadata;
import com.espertech.esper.event.EventBeanWriter;
import com.espertech.esper.event.property.Property;
import com.espertech.esper.event.property.PropertyParser;
import org.antlr.runtime.tree.Tree;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import javax.xml.namespace.QName;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* Optimistic try to resolve the property string into an appropiate xPath,
* and use it as getter.
* Mapped and Indexed properties supported.
* Because no type information is given, all property are resolved to String.
* No namespace support.
* Cannot access to xml attributes, only elements content.
*
* If an xsd is present, then use {@link com.espertech.esper.event.xml.SchemaXMLEventType SchemaXMLEventType }
*
* @author pablo
*
*/
public class SimpleXMLEventType extends BaseXMLEventType {
private static final Log log = LogFactory.getLog(SimpleXMLEventType.class);
private final Map<String, EventPropertyGetter> propertyGetterCache;
private String defaultNamespacePrefix;
private final boolean isResolvePropertiesAbsolute;
/**
* Ctor.
* @param configurationEventTypeXMLDOM configures the event type
* @param eventTypeMetadata event type metadata
* @param eventAdapterService for type looking and registration
*/
public SimpleXMLEventType(EventTypeMetadata eventTypeMetadata, ConfigurationEventTypeXMLDOM configurationEventTypeXMLDOM, EventAdapterService eventAdapterService)
{
super(eventTypeMetadata, configurationEventTypeXMLDOM, eventAdapterService);
isResolvePropertiesAbsolute = configurationEventTypeXMLDOM.isXPathResolvePropertiesAbsolute();
// Set of namespace context for XPath expressions
XPathNamespaceContext xPathNamespaceContext = new XPathNamespaceContext();
for (Map.Entry<String, String> entry : configurationEventTypeXMLDOM.getNamespacePrefixes().entrySet())
{
xPathNamespaceContext.addPrefix(entry.getKey(), entry.getValue());
}
if (configurationEventTypeXMLDOM.getDefaultNamespace() != null)
{
String defaultNamespace = configurationEventTypeXMLDOM.getDefaultNamespace();
xPathNamespaceContext.setDefaultNamespace(defaultNamespace);
// determine a default namespace prefix to use to construct XPath expressions from pure property names
defaultNamespacePrefix = null;
for (Map.Entry<String, String> entry : configurationEventTypeXMLDOM.getNamespacePrefixes().entrySet())
{
if (entry.getValue().equals(defaultNamespace))
{
defaultNamespacePrefix = entry.getKey();
break;
}
}
}
super.setNamespaceContext(xPathNamespaceContext);
super.initialize(configurationEventTypeXMLDOM.getXPathProperties().values(), Collections.EMPTY_LIST);
propertyGetterCache = new HashMap<String, EventPropertyGetter>();
}
protected Class doResolvePropertyType(String propertyExpression) {
Tree ast = PropertyParser.parse(propertyExpression);
if (PropertyParser.isPropertyDynamic(ast))
{
return org.w3c.dom.Node.class;
}
else
{
return String.class;
}
}
protected EventPropertyGetter doResolvePropertyGetter(String propertyExpression) {
EventPropertyGetter getter = propertyGetterCache.get(propertyExpression);
if (getter != null) {
return getter;
}
if (!this.getConfigurationEventTypeXMLDOM().isXPathPropertyExpr())
{
Property prop = PropertyParser.parse(propertyExpression, false);
getter = prop.getGetterDOM();
if (!prop.isDynamic())
{
getter = new DOMConvertingGetter(propertyExpression, (DOMPropertyGetter) getter, String.class);
}
}
else
{
XPathExpression xPathExpression;
String xPathExpr;
boolean isDynamic;
try
{
Tree ast = PropertyParser.parse(propertyExpression);
isDynamic = PropertyParser.isPropertyDynamic(ast);
xPathExpr = SimpleXMLPropertyParser.parse(ast, propertyExpression,getRootElementName(), defaultNamespacePrefix, isResolvePropertiesAbsolute);
XPath xpath = getXPathFactory().newXPath();
xpath.setNamespaceContext(namespaceContext);
if (log.isInfoEnabled())
{
log.info("Compiling XPath expression for property '" + propertyExpression + "' as '" + xPathExpr + "'");
}
xPathExpression = xpath.compile(xPathExpr);
}
catch (XPathExpressionException e)
{
throw new EPException("Error constructing XPath expression from property name '" + propertyExpression + '\'', e);
}
QName xPathReturnType;
if (isDynamic)
{
xPathReturnType = XPathConstants.NODE;
}
else
{
xPathReturnType = XPathConstants.STRING;
}
getter = new XPathPropertyGetter(propertyExpression, xPathExpr, xPathExpression, xPathReturnType, null, null);
}
// no fragment factory, fragments not allowed
propertyGetterCache.put(propertyExpression, getter);
return getter;
}
protected FragmentEventType doResolveFragmentType(String property)
{
return null; // Since we have no type information, the fragments are not allowed unless explicitly configured via XPath getter
}
}