/**************************************************************************************
* 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.bean;
import com.asper.sources.net.sf.cglib.reflect.FastClass;
import com.asper.sources.net.sf.cglib.reflect.FastMethod;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.PropertyAccessException;
import com.espertech.esper.event.EventAdapterService;
import com.espertech.esper.event.bean.DynamicPropertyDescriptor;
import com.espertech.esper.event.bean.BeanEventPropertyGetter;
import java.lang.reflect.Method;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* Base class for getters for a dynamic property (syntax field.inner?), caches methods to use for classes.
*/
public abstract class DynamicPropertyGetterBase implements BeanEventPropertyGetter
{
private final EventAdapterService eventAdapterService;
private final CopyOnWriteArrayList<DynamicPropertyDescriptor> cache;
/**
* To be implemented to return the method required, or null to indicate an appropriate method could not be found.
* @param clazz to search for a matching method
* @return method if found, or null if no matching method exists
*/
protected abstract Method determineMethod(Class clazz);
/**
* Call the getter to obtains the return result object, or null if no such method exists.
* @param descriptor provides method information for the class
* @param underlying is the underlying object to ask for the property value
* @return underlying
*/
protected abstract Object call(DynamicPropertyDescriptor descriptor, Object underlying);
/**
* Ctor.
* @param eventAdapterService factory for event beans and event types
*/
public DynamicPropertyGetterBase(EventAdapterService eventAdapterService)
{
this.cache = new CopyOnWriteArrayList<DynamicPropertyDescriptor>();
this.eventAdapterService = eventAdapterService;
}
public Object getBeanProp(Object object) throws PropertyAccessException
{
DynamicPropertyDescriptor desc = getPopulateCache(object);
if (desc.getMethod() == null)
{
return null;
}
return call(desc, object);
}
public boolean isBeanExistsProperty(Object object)
{
DynamicPropertyDescriptor desc = getPopulateCache(object);
if (desc.getMethod() == null)
{
return false;
}
return true;
}
public final Object get(EventBean obj) throws PropertyAccessException
{
DynamicPropertyDescriptor desc = getPopulateCache(obj.getUnderlying());
if (desc.getMethod() == null)
{
return null;
}
return call(desc, obj.getUnderlying());
}
public boolean isExistsProperty(EventBean eventBean)
{
DynamicPropertyDescriptor desc = getPopulateCache(eventBean.getUnderlying());
if (desc.getMethod() == null)
{
return false;
}
return true;
}
private DynamicPropertyDescriptor getPopulateCache(Object obj)
{
// Check if the method is already there
Class target = obj.getClass();
for (DynamicPropertyDescriptor desc : cache)
{
if (desc.getClazz() == target)
{
return desc;
}
}
// need to add it
synchronized(this)
{
for (DynamicPropertyDescriptor desc : cache)
{
if (desc.getClazz() == target)
{
return desc;
}
}
// Lookup method to use
Method method = determineMethod(target);
// Cache descriptor and create fast method
DynamicPropertyDescriptor propertyDescriptor;
if (method == null)
{
propertyDescriptor = new DynamicPropertyDescriptor(target, null, false);
}
else
{
FastClass fastClass = FastClass.create(Thread.currentThread().getContextClassLoader(), target);
FastMethod fastMethod = fastClass.getMethod(method);
propertyDescriptor = new DynamicPropertyDescriptor(target, fastMethod, fastMethod.getParameterTypes().length > 0);
}
cache.add(propertyDescriptor);
return propertyDescriptor;
}
}
public Object getFragment(EventBean eventBean)
{
Object result = get(eventBean);
return BaseNativePropertyGetter.getFragmentDynamic(result, eventAdapterService);
}
}