package org.apache.velocity.context;
/*
* 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.
*/
import java.util.HashSet;
import java.util.Set;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.util.ClassUtils;
/**
* This is a special, internal-use-only context implementation to be
* used for the #evaluate directive.
*
* We use this context to chain the existing context, preventing any changes
* from impacting the parent context. By separating this context into a
* separate class it also allows for the future possibility of changing
* the context behavior for the #evaluate directive.
*
* Note that the context used to store values local to #evaluate()
* is user defined but defaults to {@link VelocityContext}.
*
* @author <a href="mailto:[email protected]">Will Glass-Husain</a>
* @version $Id: EvaluateContext.java 898032 2010-01-11 19:51:03Z nbubna $
* @since 1.6
* @deprecated Will be removed in 2.0
*/
public class EvaluateContext extends ChainedInternalContextAdapter
{
/** container for any local items */
Context localContext;
/**
* CTOR, wraps an ICA
* @param inner context for parent template
* @param rsvc
*/
public EvaluateContext( InternalContextAdapter inner, RuntimeServices rsvc )
{
super(inner);
initContext(rsvc);
}
/**
* Initialize the context based on user-configured class
* @param rsvc
*/
private void initContext( RuntimeServices rsvc )
{
String contextClass = rsvc.getString(RuntimeConstants.EVALUATE_CONTEXT_CLASS);
if (contextClass != null && contextClass.length() > 0)
{
rsvc.getLog().warn("The "+RuntimeConstants.EVALUATE_CONTEXT_CLASS+
" property has been deprecated. It will be removed in Velocity 2.0. "+
" Instead, please use the automatically provided $evaluate"+
" namespace to get and set local references"+
" (e.g. #set($evaluate.foo = 'bar') and $evaluate.foo).");
Object o = null;
try
{
o = ClassUtils.getNewInstance( contextClass );
}
catch (ClassNotFoundException cnfe)
{
String err = "The specified class for #evaluate() context (" + contextClass
+ ") does not exist or is not accessible to the current classloader.";
rsvc.getLog().error(err);
throw new RuntimeException(err,cnfe);
}
catch (Exception e)
{
String err = "The specified class for #evaluate() context (" + contextClass
+ ") can not be loaded.";
rsvc.getLog().error(err,e);
throw new RuntimeException(err);
}
if (!(o instanceof Context))
{
String err = "The specified class for #evaluate() context (" + contextClass
+ ") does not implement " + Context.class.getName() + ".";
rsvc.getLog().error(err);
throw new RuntimeException(err);
}
localContext = (Context) o;
}
else
{
if (rsvc.getLog().isDebugEnabled())
{
rsvc.getLog().debug("No class specified for #evaluate() context, "+
"so #set calls will now alter the global context and no longer be local. "+
"This is a change from earlier versions due to VELOCITY-704. "+
"If you need references within #evaluate to stay local, "+
"please use the automatically provided $evaluate namespace instead "+
"(e.g. #set($evaluate.foo = 'bar') and $evaluate.foo).");
}
}
}
/**
* Put method also stores values in local scope
*
* @param key name of item to set
* @param value object to set to key
* @return old stored object
*/
public Object put(String key, Object value)
{
if (localContext != null)
{
return localContext.put(key, value);
}
return super.put(key, value);
}
/**
* Retrieves from local or global context.
*
* @param key name of item to get
* @return stored object or null
*/
public Object get( String key )
{
/*
* always try the local context then innerContext
*/
Object o = null;
if (localContext != null)
{
o = localContext.get(key);
}
if (o == null)
{
o = super.get( key );
}
return o;
}
/**
* @see org.apache.velocity.context.Context#containsKey(java.lang.Object)
*/
public boolean containsKey(Object key)
{
return (localContext != null && localContext.containsKey(key)) ||
super.containsKey(key);
}
/**
* @see org.apache.velocity.context.Context#getKeys()
*/
public Object[] getKeys()
{
if (localContext != null)
{
Set keys = new HashSet();
Object[] localKeys = localContext.getKeys();
for (int i=0; i < localKeys.length; i++)
{
keys.add(localKeys[i]);
}
Object[] innerKeys = super.getKeys();
for (int i=0; i < innerKeys.length; i++)
{
keys.add(innerKeys[i]);
}
return keys.toArray();
}
return super.getKeys();
}
/**
* @see org.apache.velocity.context.Context#remove(java.lang.Object)
*/
public Object remove(Object key)
{
if (localContext != null)
{
return localContext.remove(key);
}
return super.remove(key);
}
/**
* Allows callers to explicitly put objects in the local context.
* Objects added to the context through this method always end up
* in the top-level context of possible wrapped contexts.
*
* @param key name of item to set.
* @param value object to set to key.
* @return old stored object
*/
public Object localPut(final String key, final Object value)
{
if (localContext != null)
{
return localContext.put(key, value);
}
return super.localPut(key, value);
}
}
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