package org.apache.velocity.runtime.parser.node;
/*
* 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.lang.reflect.InvocationTargetException;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.velocity.app.event.EventHandlerUtil;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.exception.VelocityException;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.parser.Parser;
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 720228 2008-11-24 16:58:33Z nbubna $
*/
public class ASTMethod extends SimpleNode
{
private String methodName = "";
private int paramCount = 0;
protected Info uberInfo;
/**
* Indicates if we are running in strict reference mode.
*/
protected boolean strictRef = false;
/**
* @param id
*/
public ASTMethod(int id)
{
super(id);
}
/**
* @param p
* @param id
*/
public ASTMethod(Parser p, int id)
{
super(p, id);
}
/**
* @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
*/
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
* @param context
* @param data
* @return The init result
* @throws TemplateInitException
*/
public Object init( InternalContextAdapter context, Object data)
throws TemplateInitException
{
super.init( context, data );
/*
* make an uberinfo - saves new's later on
*/
uberInfo = new Info(getTemplateName(),
getLine(),getColumn());
/*
* this is about all we can do
*/
methodName = getFirstToken().image;
paramCount = jjtGetNumChildren() - 1;
strictRef = rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false);
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
* @param o
* @param context
* @return Result or null.
* @throws MethodInvocationException
*/
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
*/
final Class[] paramClasses = paramCount > 0 ? new Class[paramCount] : ArrayUtils.EMPTY_CLASS_ARRAY;
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(methodName, 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
*/
method = rsvc.getUberspect().getMethod(o, methodName, params, new Info(getTemplateName(), 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)
{
if (strictRef)
{
// Create a parameter list for the exception error message
StringBuffer plist = new StringBuffer();
for (int i=0; i<params.length; i++)
{
Class param = paramClasses[i];
plist.append(param == null ? "null" : param.getName());
if (i < params.length -1) plist.append(", ");
}
throw new MethodInvocationException("Object '" + o.getClass().getName() +
"' does not contain method " + methodName + "(" + plist + ")",
null, methodName, uberInfo.getTemplateName(), uberInfo.getLine(), uberInfo.getColumn());
}
else
{
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
*/
String msg = "ASTMethod.execute() : exception from introspection";
log.error(msg, e);
throw new VelocityException(msg, e);
}
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 )
{
return handleInvocationException(o, context, ite.getTargetException());
}
/** Can also be thrown by method invocation **/
catch( IllegalArgumentException t )
{
return handleInvocationException(o, context, t);
}
/**
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch( Exception e )
{
String msg = "ASTMethod.execute() : exception invoking method '"
+ methodName + "' in " + o.getClass();
log.error(msg, e);
throw new VelocityException(msg, e);
}
}
private Object handleInvocationException(Object o, InternalContextAdapter context, Throwable t)
{
/*
* 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...
*/
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()
+ " threw exception "
+ e.toString(),
e, methodName, getTemplateName(), this.getLine(), this.getColumn());
}
}
else
{
/*
* no event cartridge to override. Just throw
*/
throw new MethodInvocationException(
"Invocation of method '"
+ methodName + "' in " + o.getClass()
+ " threw exception "
+ t.toString(),
t, methodName, getTemplateName(), this.getLine(), this.getColumn());
}
}
/**
* Internal class used as key for method cache. Combines
* ASTMethod fields with array of parameter classes. Has
* public access (and complete constructor) for unit test
* purposes.
* @since 1.5
*/
public static class MethodCacheKey
{
private final String methodName;
private final Class[] params;
public MethodCacheKey(String methodName, Class[] params)
{
/**
* Should never be initialized with nulls, but to be safe we refuse
* to accept them.
*/
this.methodName = (methodName != null) ? methodName : StringUtils.EMPTY;
this.params = (params != null) ? params : ArrayUtils.EMPTY_CLASS_ARRAY;
}
/**
* @see java.lang.Object#equals(java.lang.Object)
*/
public boolean equals(Object o)
{
/**
* note we skip the null test for methodName and params
* due to the earlier test in the constructor
*/
if (o instanceof MethodCacheKey)
{
final MethodCacheKey other = (MethodCacheKey) o;
if (params.length == other.params.length &&
methodName.equals(other.methodName))
{
for (int i = 0; i < params.length; ++i)
{
if (params[i] == null)
{
if (params[i] != other.params[i])
{
return false;
}
}
else if (!params[i].equals(other.params[i]))
{
return false;
}
}
return true;
}
}
return false;
}
/**
* @see java.lang.Object#hashCode()
*/
public int hashCode()
{
int result = 17;
/**
* note we skip the null test for methodName and params
* due to the earlier test in the constructor
*/
for (int i = 0; i < params.length; ++i)
{
final Class param = params[i];
if (param != null)
{
result = result * 37 + param.hashCode();
}
}
result = result * 37 + methodName.hashCode();
return result;
}
}
/**
* @return Returns the methodName.
* @since 1.5
*/
public String getMethodName()
{
return methodName;
}
}