package org.apache.velocity.runtime.parser.node;
/*
* Copyright 2000-2004 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.
*/
import java.lang.reflect.InvocationTargetException;
import org.apache.velocity.app.event.EventHandlerUtil;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.runtime.parser.Parser;
import org.apache.velocity.runtime.parser.ParserVisitor;
import org.apache.velocity.util.introspection.Info;
import org.apache.velocity.util.introspection.IntrospectionCacheData;
import org.apache.velocity.util.introspection.VelMethod;
/**
* ASTMethod.java
*
* Method support for references : $foo.method()
*
* NOTE :
*
* introspection is now done at render time.
*
* Please look at the Parser.jjt file which is
* what controls the generation of this class.
*
* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @version $Id: ASTMethod.java 373415 2006-01-30 02:34:47Z wglass $
*/
public class ASTMethod extends SimpleNode
{
private String methodName = "";
private int paramCount = 0;
public ASTMethod(int id)
{
super(id);
}
public ASTMethod(Parser p, int id)
{
super(p, id);
}
/** Accept the visitor. **/
public Object jjtAccept(ParserVisitor visitor, Object data)
{
return visitor.visit(this, data);
}
/**
* simple init - init our subtree and get what we can from
* the AST
*/
public Object init( InternalContextAdapter context, Object data)
throws Exception
{
super.init( context, data );
/*
* this is about all we can do
*/
methodName = getFirstToken().image;
paramCount = jjtGetNumChildren() - 1;
return data;
}
/**
* invokes the method. Returns null if a problem, the
* actual return if the method returns something, or
* an empty string "" if the method returns void
*/
public Object execute(Object o, InternalContextAdapter context)
throws MethodInvocationException
{
/*
* new strategy (strategery!) for introspection. Since we want
* to be thread- as well as context-safe, we *must* do it now,
* at execution time. There can be no in-node caching,
* but if we are careful, we can do it in the context.
*/
VelMethod method = null;
Object [] params = new Object[paramCount];
try
{
/*
* sadly, we do need recalc the values of the args, as this can
* change from visit to visit
*/
Class[] paramClasses = new Class[paramCount];
for (int j = 0; j < paramCount; j++)
{
params[j] = jjtGetChild(j + 1).value(context);
if (params[j] != null)
{
paramClasses[j] = params[j].getClass();
}
}
/*
* check the cache
*/
MethodCacheKey mck = new MethodCacheKey(paramClasses);
IntrospectionCacheData icd = context.icacheGet( mck );
/*
* like ASTIdentifier, if we have cache information, and the
* Class of Object o is the same as that in the cache, we are
* safe.
*/
if ( icd != null && (o != null && icd.contextData == o.getClass()) )
{
/*
* get the method from the cache
*/
method = (VelMethod) icd.thingy;
}
else
{
/*
* otherwise, do the introspection, and then
* cache it
*/
for (int j = 0; j < paramCount; j++)
params[j] = jjtGetChild(j + 1).value(context);
method = rsvc.getUberspect().getMethod(o, methodName, params, new Info(context.getCurrentTemplateName(), getLine(), getColumn()));
if ((method != null) && (o != null))
{
icd = new IntrospectionCacheData();
icd.contextData = o.getClass();
icd.thingy = method;
context.icachePut( mck, icd );
}
}
/*
* if we still haven't gotten the method, either we are calling
* a method that doesn't exist (which is fine...) or I screwed
* it up.
*/
if (method == null)
return null;
}
catch( MethodInvocationException mie )
{
/*
* this can come from the doIntrospection(), as the arg values
* are evaluated to find the right method signature. We just
* want to propogate it here, not do anything fancy
*/
throw mie;
}
/**
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch( Exception e )
{
/*
* can come from the doIntropection() also, from Introspector
*/
log.error("ASTMethod.execute() : exception from introspection", e);
return null;
}
try
{
/*
* get the returned object. It may be null, and that is
* valid for something declared with a void return type.
* Since the caller is expecting something to be returned,
* as long as things are peachy, we can return an empty
* String so ASTReference() correctly figures out that
* all is well.
*/
Object obj = method.invoke(o, params);
if (obj == null)
{
if( method.getReturnType() == Void.TYPE)
{
return "";
}
}
return obj;
}
catch( InvocationTargetException ite )
{
/*
* In the event that the invocation of the method
* itself throws an exception, we want to catch that
* wrap it, and throw. We don't log here as we want to figure
* out which reference threw the exception, so do that
* above
*/
/*
* let non-Exception Throwables go...
*/
Throwable t = ite.getTargetException();
if (t instanceof Exception)
{
try
{
return EventHandlerUtil.methodException( rsvc, context, o.getClass(), methodName, (Exception) t );
}
/**
* If the event handler throws an exception, then wrap it
* in a MethodInvocationException. Don't pass through RuntimeExceptions like other
* similar catchall code blocks.
*/
catch( Exception e )
{
throw new MethodInvocationException(
"Invocation of method '"
+ methodName + "' in " + o.getClass()
+ " in template " + context.getCurrentTemplateName()
+ " at line=" + this.getLine() + " column=" + this.getColumn()
+ " threw exception "
+ e.getClass() + " : " + e.getMessage(),
e, methodName );
}
}
else
{
/*
* no event cartridge to override. Just throw
*/
throw new MethodInvocationException(
"Invocation of method '"
+ methodName + "' in " + o.getClass()
+ " in template " + context.getCurrentTemplateName()
+ " at line=" + this.getLine() + " column=" + this.getColumn()
+ " threw exception "
+ ite.getTargetException().getClass() + " : "
+ ite.getTargetException().getMessage(),
ite.getTargetException(), methodName );
}
}
/**
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch( Exception e )
{
log.error("ASTMethod.execute() : exception invoking method '"
+ methodName + "' in " + o.getClass(), e);
return null;
}
}
/**
* Internal class used as key for method cache. Combines
* ASTMethod fields with array of parameter classes.
*/
class MethodCacheKey
{
Class[] params;
MethodCacheKey(Class[] params)
{
this.params = params;
}
public boolean equals(Object o)
{
return (o != null) &&
(o instanceof MethodCacheKey) &&
(this.hashCode() == o.hashCode());
}
public int hashCode()
{
return params.hashCode() * 37 + ASTMethod.this.hashCode();
}
}
}