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/*
* 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.apache.naming.factory;
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NamingException;
import javax.naming.RefAddr;
import javax.naming.Reference;
import javax.naming.spi.ObjectFactory;
/**
* Abstract base class that provides common functionality required by
* sub-classes. This class exists primarily to reduce code duplication.
*/
public abstract class FactoryBase implements ObjectFactory {
/**
* Creates a new object instance.
*
* @param obj The reference object describing the object to create
*/
@Override
public final Object getObjectInstance(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment) throws Exception {
if (isReferenceTypeSupported(obj)) {
Reference ref = (Reference) obj;
Object linked = getLinked(ref);
if (linked != null) {
return linked;
}
ObjectFactory factory = null;
RefAddr factoryRefAddr = ref.get(Constants.FACTORY);
if (factoryRefAddr != null) {
// Using the specified factory
String factoryClassName = factoryRefAddr.getContent().toString();
// Loading factory
ClassLoader tcl = Thread.currentThread().getContextClassLoader();
Class<?> factoryClass = null;
try {
if (tcl != null) {
factoryClass = tcl.loadClass(factoryClassName);
} else {
factoryClass = Class.forName(factoryClassName);
}
} catch(ClassNotFoundException e) {
NamingException ex = new NamingException(
"Could not load resource factory class");
ex.initCause(e);
throw ex;
}
try {
factory = (ObjectFactory) factoryClass.newInstance();
} catch(Throwable t) {
if (t instanceof NamingException) {
throw (NamingException) t;
}
if (t instanceof ThreadDeath) {
throw (ThreadDeath) t;
}
if (t instanceof VirtualMachineError) {
throw (VirtualMachineError) t;
}
NamingException ex = new NamingException(
"Could not create resource factory instance");
ex.initCause(t);
throw ex;
}
} else {
// Check for a default factory
factory = getDefaultFactory(ref);
}
if (factory != null) {
return factory.getObjectInstance(obj, name, nameCtx, environment);
} else {
throw new NamingException("Cannot create resource instance");
}
}
return null;
}
/**
* Determines if this factory supports processing the provided reference
* object.
*
* @param obj The object to be processed
*
* @return <code>true</code> if this factory can process the object,
* otherwise <code>false</code>
*/
protected abstract boolean isReferenceTypeSupported(Object obj);
/**
* If a default factory is available for the given reference type, create
* the default factory.
*
* @param ref The reference object to be processed
*
* @return The default factory for the given reference object or
* <code>null</code> if no default factory exists.
*
* @throws NamingException If the default factory can not be craeted
*/
protected abstract ObjectFactory getDefaultFactory(Reference ref)
throws NamingException;
/**
* If this reference is a link to another JNDI object, obtain that object.
*
* @param ref The reference object to be processed
*
* @return The linked object or <code>null</code> if linked objects are
* not supported by or not configured for this reference object
*/
protected abstract Object getLinked(Reference ref) throws NamingException;
}
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