/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed 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.taglibs.standard.lang.jstl;
import java.beans.BeanInfo;
import java.beans.EventSetDescriptor;
import java.beans.IndexedPropertyDescriptor;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
/**
*
* <p>Manages the BeanInfo for one class - contains the BeanInfo, and
* also a mapping from property name to BeanInfoProperty. There are
* also static methods for accessing the BeanInfoManager for a class -
* those mappings are cached permanently so that once the
* BeanInfoManager is calculated, it doesn't have to be calculated
* again.
*
* @author Nathan Abramson - Art Technology Group
* @version $Change: 181181 $$DateTime: 2001/06/26 09:55:09 $$Author: pierred $
**/
public class BeanInfoManager
{
//-------------------------------------
// Properties
//-------------------------------------
// property beanClass
Class mBeanClass;
public Class getBeanClass ()
{ return mBeanClass; }
//-------------------------------------
// Member variables
//-------------------------------------
// The BeanInfo
BeanInfo mBeanInfo;
// Mapping from property name to BeanInfoProperty
Map mPropertyByName;
// Mapping from property name to BeanInfoIndexedProperty
Map mIndexedPropertyByName;
// Mapping from event set name to event set descriptor
Map mEventSetByName;
// Flag if this is initialized
boolean mInitialized;
// The global mapping from class to BeanInfoManager
static Map mBeanInfoManagerByClass = new HashMap ();
//-------------------------------------
/**
*
* Constructor
**/
BeanInfoManager (Class pBeanClass)
{
mBeanClass = pBeanClass;
}
//-------------------------------------
/**
*
* Returns the BeanInfoManager for the specified class
**/
public static BeanInfoManager getBeanInfoManager (Class pClass)
{
BeanInfoManager ret = (BeanInfoManager)
mBeanInfoManagerByClass.get (pClass);
if (ret == null) {
ret = createBeanInfoManager (pClass);
}
return ret;
}
//-------------------------------------
/**
*
* Creates and registers the BeanInfoManager for the given class if
* it isn't already registered.
**/
static synchronized BeanInfoManager createBeanInfoManager (Class pClass)
{
// Because this method is synchronized statically, the
// BeanInfoManager is not initialized at this time (otherwise it
// could end up being a bottleneck for the entire system). It is
// put into the map in an uninitialized state. The first time
// someone tries to use it, it will be initialized (with proper
// synchronizations in place to make sure it is only initialized
// once).
BeanInfoManager ret = (BeanInfoManager)
mBeanInfoManagerByClass.get (pClass);
if (ret == null) {
ret = new BeanInfoManager (pClass);
mBeanInfoManagerByClass.put (pClass, ret);
}
return ret;
}
//-------------------------------------
/**
*
* Returns the BeanInfoProperty for the specified property in the
* given class, or null if not found.
**/
public static BeanInfoProperty getBeanInfoProperty
(Class pClass,
String pPropertyName,
Logger pLogger)
throws ELException
{
return getBeanInfoManager (pClass).getProperty (pPropertyName, pLogger);
}
//-------------------------------------
/**
*
* Returns the BeanInfoIndexedProperty for the specified property in
* the given class, or null if not found.
**/
public static BeanInfoIndexedProperty getBeanInfoIndexedProperty
(Class pClass,
String pIndexedPropertyName,
Logger pLogger)
throws ELException
{
return getBeanInfoManager
(pClass).getIndexedProperty (pIndexedPropertyName, pLogger);
}
//-------------------------------------
/**
*
* Makes sure that this class has been initialized, and synchronizes
* the initialization if it's required.
**/
void checkInitialized (Logger pLogger)
throws ELException
{
if (!mInitialized) {
synchronized (this) {
if (!mInitialized) {
initialize (pLogger);
mInitialized = true;
}
}
}
}
//-------------------------------------
/**
*
* Initializes by mapping property names to BeanInfoProperties
**/
void initialize (Logger pLogger)
throws ELException
{
try {
mBeanInfo = Introspector.getBeanInfo (mBeanClass);
mPropertyByName = new HashMap ();
mIndexedPropertyByName = new HashMap ();
PropertyDescriptor [] pds = mBeanInfo.getPropertyDescriptors ();
for (int i = 0; pds != null && i < pds.length; i++) {
// Treat as both an indexed property and a normal property
PropertyDescriptor pd = pds [i];
if (pd instanceof IndexedPropertyDescriptor) {
IndexedPropertyDescriptor ipd = (IndexedPropertyDescriptor) pd;
Method readMethod = getPublicMethod (ipd.getIndexedReadMethod ());
Method writeMethod = getPublicMethod (ipd.getIndexedWriteMethod ());
BeanInfoIndexedProperty property = new BeanInfoIndexedProperty
(readMethod,
writeMethod,
ipd);
mIndexedPropertyByName.put (ipd.getName (), property);
}
Method readMethod = getPublicMethod (pd.getReadMethod ());
Method writeMethod = getPublicMethod (pd.getWriteMethod ());
BeanInfoProperty property = new BeanInfoProperty
(readMethod,
writeMethod,
pd);
mPropertyByName.put (pd.getName (), property);
}
mEventSetByName = new HashMap ();
EventSetDescriptor [] esds = mBeanInfo.getEventSetDescriptors ();
for (int i = 0; esds != null && i < esds.length; i++) {
EventSetDescriptor esd = esds [i];
mEventSetByName.put (esd.getName (), esd);
}
}
catch (IntrospectionException exc) {
if (pLogger.isLoggingWarning ()) {
pLogger.logWarning
(Constants.EXCEPTION_GETTING_BEANINFO,
exc,
mBeanClass.getName ());
}
}
}
//-------------------------------------
/**
*
* Returns the BeanInfo for the class
**/
BeanInfo getBeanInfo (Logger pLogger)
throws ELException
{
checkInitialized (pLogger);
return mBeanInfo;
}
//-------------------------------------
/**
*
* Returns the BeanInfoProperty for the given property name, or null
* if not found.
**/
public BeanInfoProperty getProperty (String pPropertyName,
Logger pLogger)
throws ELException
{
checkInitialized (pLogger);
return (BeanInfoProperty) mPropertyByName.get (pPropertyName);
}
//-------------------------------------
/**
*
* Returns the BeanInfoIndexedProperty for the given property name,
* or null if not found.
**/
public BeanInfoIndexedProperty getIndexedProperty
(String pIndexedPropertyName,
Logger pLogger)
throws ELException
{
checkInitialized (pLogger);
return (BeanInfoIndexedProperty)
mIndexedPropertyByName.get (pIndexedPropertyName);
}
//-------------------------------------
/**
*
* Returns the EventSetDescriptor for the given event set name, or
* null if not found.
**/
public EventSetDescriptor getEventSet (String pEventSetName,
Logger pLogger)
throws ELException
{
checkInitialized (pLogger);
return (EventSetDescriptor) mEventSetByName.get (pEventSetName);
}
//-------------------------------------
// Finding the public version of a method - if a PropertyDescriptor
// is obtained for a non-public class that implements a public
// interface, the read/write methods will be for the class, and
// therefore inaccessible. To correct this, a version of the same
// method must be found in a superclass or interface.
//-------------------------------------
/**
*
* Returns a publicly-accessible version of the given method, by
* searching for a public declaring class.
**/
static Method getPublicMethod (Method pMethod)
{
if (pMethod == null) {
return null;
}
// See if the method is already available from a public class
Class cl = pMethod.getDeclaringClass ();
if (Modifier.isPublic (cl.getModifiers ())) {
return pMethod;
}
// Otherwise, try to find a public class that declares the method
Method ret = getPublicMethod (cl, pMethod);
if (ret != null) {
return ret;
}
else {
return pMethod;
}
}
//-------------------------------------
/**
*
* If the given class is public and has a Method that declares the
* same name and arguments as the given method, then that method is
* returned. Otherwise the superclass and interfaces are searched
* recursively.
**/
static Method getPublicMethod (Class pClass,
Method pMethod)
{
// See if this is a public class declaring the method
if (Modifier.isPublic (pClass.getModifiers ())) {
try {
Method m;
try {
m = pClass.getDeclaredMethod (pMethod.getName (),
pMethod.getParameterTypes ());
} catch (java.security.AccessControlException ex) {
// kludge to accommodate J2EE RI's default settings
// TODO: see if we can simply replace
// getDeclaredMethod() with getMethod() ...?
m = pClass.getMethod(pMethod.getName (),
pMethod.getParameterTypes ());
}
if (Modifier.isPublic (m.getModifiers ())) {
return m;
}
}
catch (NoSuchMethodException exc) {}
}
// Search the interfaces
{
Class [] interfaces = pClass.getInterfaces ();
if (interfaces != null) {
for (int i = 0; i < interfaces.length; i++) {
Method m = getPublicMethod (interfaces [i], pMethod);
if (m != null) {
return m;
}
}
}
}
// Search the superclass
{
Class superclass = pClass.getSuperclass ();
if (superclass != null) {
Method m = getPublicMethod (superclass, pMethod);
if (m != null) {
return m;
}
}
}
return null;
}
//-------------------------------------
}