package org.apache.velocity.runtime.parser.node;
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.log.Log;
import org.apache.velocity.runtime.parser.Parser;
import org.apache.velocity.util.ClassUtils;
import org.apache.velocity.util.introspection.VelMethod;
/*
* 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.
*/
/**
* This node is responsible for the bracket notation at the end of
* a reference, e.g., $foo[1]
*/
public class ASTIndex extends SimpleNode
{
private final String methodName = "get";
/**
* Indicates if we are running in strict reference mode.
*/
protected boolean strictRef = false;
public ASTIndex(int i)
{
super(i);
}
public ASTIndex(Parser p, int i)
{
super(p, i);
}
public Object init(InternalContextAdapter context, Object data)
throws TemplateInitException
{
super.init(context, data);
strictRef = rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false);
return data;
}
private final static Object[] noParams = {};
private final static Class[] noTypes = {};
/**
* If argument is an Integer and negative, then return (o.size() - argument).
* Otherwise return the original argument. We use this to calculate the true
* index of a negative index e.g., $foo[-1]. If no size() method is found on the
* 'o' object, then we throw an VelocityException.
* @param context Used to access the method cache.
* @param node ASTNode used for error reporting.
*/
public static Object adjMinusIndexArg(Object argument, Object o,
InternalContextAdapter context, SimpleNode node)
{
if (argument instanceof Integer && ((Integer)argument).intValue() < 0)
{
// The index value is a negative number, $foo[-1], so we want to actually
// Index [size - value], so try and call the size method.
VelMethod method = ClassUtils.getMethod("size", noParams, noTypes,
o, context, node, false);
if (method == null)
{
// The object doesn't have a size method, so there is no notion of "at the end"
throw new VelocityException(
"A 'size()' method required for negative value "
+ ((Integer)argument).intValue() + " does not exist for class '"
+ o.getClass().getName() + "' at " + Log.formatFileString(node));
}
Object size = null;
try
{
size = method.invoke(o, noParams);
}
catch (Exception e)
{
throw new VelocityException("Error trying to calls the 'size()' method on '"
+ o.getClass().getName() + "' at " + Log.formatFileString(node), e);
}
int sizeint = 0;
try
{
sizeint = ((Integer)size).intValue();
}
catch (ClassCastException e)
{
// If size() doesn't return an Integer we want to report a pretty error
throw new VelocityException("Method 'size()' on class '"
+ o.getClass().getName() + "' returned '" + size.getClass().getName()
+ "' when Integer was expected at " + Log.formatFileString(node));
}
argument = new Integer(sizeint + ((Integer)argument).intValue());
}
// Nothing to do, return the original argument
return argument;
}
public Object execute(Object o, InternalContextAdapter context)
throws MethodInvocationException
{
Object argument = jjtGetChild(0).value(context);
// If negative, turn -1 into size - 1
argument = adjMinusIndexArg(argument, o, context, this);
Object [] params = {argument};
Class[] paramClasses = {argument == null ? null : argument.getClass()};
VelMethod method = ClassUtils.getMethod(methodName, params, paramClasses,
o, context, this, strictRef);
if (method == null) 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;
}
/**
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch( Exception e )
{
String msg = "Error invoking method 'get("
+ (argument == null ? "null" : argument.getClass().getName())
+ ")' in " + o.getClass().getName()
+ " at " + Log.formatFileString(this);
log.error(msg, e);
throw new VelocityException(msg, e);
}
}
}