package org.apache.velocity.runtime.parser.node;
/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Velocity", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
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*
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
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*/
import java.io.Writer;
import java.io.IOException;
import java.util.Map;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import org.apache.velocity.context.Context;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.exception.ReferenceException;
import org.apache.velocity.runtime.parser.*;
import org.apache.velocity.util.introspection.Introspector;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.app.event.EventCartridge;
import org.apache.velocity.app.event.ReferenceInsertionEventHandler;
/**
* This class is responsible for handling the references in
* VTL ($foo).
*
* 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>
* @author <a href="mailto:Christoph.Reck@dlr.de">Christoph Reck</a>
* @author <a href="mailto:kjohnson@transparent.com>Kent Johnson</a>
* @version $Id: ASTReference.java,v 1.43 2002/02/23 11:00:40 geirm Exp $
*/
public class ASTReference extends SimpleNode
{
/* Reference types */
private static final int NORMAL_REFERENCE = 1;
private static final int FORMAL_REFERENCE = 2;
private static final int QUIET_REFERENCE = 3;
private static final int RUNT = 4;
private int referenceType;
private String nullString;
private String rootString;
private boolean escaped = false;
private boolean computableReference = true;
private String escPrefix = "";
private String morePrefix = "";
private String identifier = "";
private String literal = null;
private int numChildren = 0;
public ASTReference(int id)
{
super(id);
}
public ASTReference(Parser p, int id)
{
super(p, id);
}
/** Accept the visitor. **/
public Object jjtAccept(ParserVisitor visitor, Object data)
{
return visitor.visit(this, data);
}
public Object init( InternalContextAdapter context, Object data)
throws Exception
{
/*
* init our children
*/
super.init( context, data );
/*
* the only thing we can do in init() is getRoot()
* as that is template based, not context based,
* so it's thread- and context-safe
*/
rootString = getRoot();
numChildren = jjtGetNumChildren();
/*
* and if appropriate...
*/
if (numChildren > 0 )
{
identifier = jjtGetChild(numChildren - 1).getFirstToken().image;
}
return data;
}
/**
* Returns the 'root string', the reference key
*/
public String getRootString()
{
return rootString;
}
/**
* gets an Object that 'is' the value of the reference
*
* @param o unused Object parameter
* @param context context used to generate value
*/
public Object execute(Object o, InternalContextAdapter context)
throws MethodInvocationException
{
if ( referenceType == RUNT )
return null;
/*
* get the root object from the context
*/
Object result = getVariableValue(context, rootString);
if (result == null)
{
return null;
}
/*
* Iteratively work 'down' (it's flat...) the reference
* to get the value, but check to make sure that
* every result along the path is valid. For example:
*
* $hashtable.Customer.Name
*
* The $hashtable may be valid, but there is no key
* 'Customer' in the hashtable so we want to stop
* when we find a null value and return the null
* so the error gets logged.
*/
try
{
for (int i = 0; i < numChildren; i++)
{
result = jjtGetChild(i).execute(result,context);
if (result == null)
{
return null;
}
}
return result;
}
catch( MethodInvocationException mie)
{
/*
* someone tossed their cookies
*/
rsvc.error("Method " + mie.getMethodName() + " threw exception for reference $"
+ rootString
+ " in template " + context.getCurrentTemplateName()
+ " at " + " [" + this.getLine() + "," + this.getColumn() + "]");
mie.setReferenceName( rootString );
throw mie;
}
}
/**
* gets the value of the reference and outputs it to the
* writer.
*
* @param context context of data to use in getting value
* @param writer writer to render to
*/
public boolean render( InternalContextAdapter context, Writer writer)
throws IOException, MethodInvocationException
{
if (referenceType == RUNT )
{
writer.write( rootString );
return true;
}
Object value = execute(null, context);
/*
* if this reference is escaped (\$foo) then we want to do one of two things :
* 1) if this is a reference in the context, then we want to print $foo
* 2) if not, then \$foo (its considered shmoo, not VTL)
*/
if ( escaped )
{
if ( value == null )
{
writer.write( escPrefix );
writer.write( "\\" );
writer.write( nullString );
}
else
{
writer.write( escPrefix );
writer.write( nullString );
}
return true;
}
/*
* the normal processing
*
* if we have an event cartridge, get a new value object
*/
EventCartridge ec = context.getEventCartridge();
if (ec != null)
{
value = ec.referenceInsert( nullString, value );
}
/*
* if value is null...
*/
if (value == null)
{
/*
* write prefix twice, because it's shmoo, so the \ don't escape each other...
*/
writer.write( escPrefix );
writer.write( escPrefix );
writer.write( morePrefix );
writer.write( nullString );
if (referenceType != QUIET_REFERENCE
&& rsvc.getBoolean(
RuntimeConstants.RUNTIME_LOG_REFERENCE_LOG_INVALID, true) )
{
rsvc.warn(new ReferenceException("reference : template = "
+ context.getCurrentTemplateName(), this));
}
return true;
}
else
{
/*
* non-null processing
*/
writer.write( escPrefix );
writer.write( morePrefix );
writer.write( value.toString() );
return true;
}
}
/**
* Computes boolean value of this reference
* Returns the actual value of reference return type
* boolean, and 'true' if value is not null
*
* @param context context to compute value with
*/
public boolean evaluate( InternalContextAdapter context)
throws MethodInvocationException
{
Object value = execute(null, context);
if (value == null)
{
return false;
}
else if (value instanceof Boolean)
{
if (((Boolean) value).booleanValue())
return true;
else
return false;
}
else
return true;
}
public Object value( InternalContextAdapter context)
throws MethodInvocationException
{
return ( computableReference ? execute(null, context) : null );
}
/**
* Sets the value of a complex reference (something like $foo.bar)
* Currently used by ASTSetReference()
*
* @see ASTSetDirective
*
* @param context context object containing this reference
* @param value Object to set as value
* @return true if successful, false otherwise
*/
public boolean setValue( InternalContextAdapter context, Object value)
throws MethodInvocationException
{
/*
* The rootOfIntrospection is the object we will
* retrieve from the Context. This is the base
* object we will apply reflection to.
*/
Object result = getVariableValue(context, rootString);
if (result == null)
{
rsvc.error(new ReferenceException("reference set : template = " + context.getCurrentTemplateName(), this));
return false;
}
/*
* How many child nodes do we have?
*/
for (int i = 0; i < numChildren - 1; i++)
{
result = jjtGetChild(i).execute(result, context);
if (result == null)
{
rsvc.error(new ReferenceException("reference set : template = " + context.getCurrentTemplateName(), this));
return false;
}
}
/*
* We support two ways of setting the value in a #set($ref.foo = $value ) :
* 1) ref.setFoo( value )
* 2) ref,put("foo", value ) to parallel the get() map introspection
*/
try
{
/*
* first, we introspect for the set<identifier> setter method
*/
Object[] params = { value };
Class c = result.getClass();
Method m = null;
try
{
m = rsvc.getIntrospector().getMethod( c, "set" + identifier, params);
if (m == null)
{
throw new NoSuchMethodException();
}
}
catch( NoSuchMethodException nsme2)
{
StringBuffer sb = new StringBuffer( "set" );
sb.append( identifier );
if( Character.isLowerCase( sb.charAt(3)))
{
sb.setCharAt( 3 , Character.toUpperCase( sb.charAt( 3 ) ) );
}
else
{
sb.setCharAt( 3 , Character.toLowerCase( sb.charAt( 3 ) ) );
}
m = rsvc.getIntrospector().getMethod( c, sb.toString(), params);
if (m == null)
{
throw new NoSuchMethodException();
}
}
/*
* and if we get here, getMethod() didn't chuck an exception...
*/
Object[] args = { value };
m.invoke(result, args);
}
catch (NoSuchMethodException nsme)
{
/*
* right now, we only support the Map interface
*/
if (result instanceof Map)
{
try
{
((Map) result).put(identifier, value);
}
catch (Exception ex)
{
rsvc.error("ASTReference Map.put : exception : " + ex
+ " template = " + context.getCurrentTemplateName()
+ " [" + this.getLine() + "," + this.getColumn() + "]");
return false;
}
}
else
{
rsvc.error("ASTReference : cannot find " + identifier + " as settable property or key to Map in"
+ " template = " + context.getCurrentTemplateName()
+ " [" + this.getLine() + "," + this.getColumn() + "]");
return false;
}
}
catch( InvocationTargetException ite )
{
/*
* this is possible
*/
throw new MethodInvocationException(
"ASTReference : Invocation of method '"
+ identifier + "' in " + result.getClass()
+ " threw exception "
+ ite.getTargetException().getClass(),
ite.getTargetException(), identifier );
}
catch( Exception e )
{
/*
* maybe a security exception?
*/
rsvc.error("ASTReference setValue() : exception : " + e
+ " template = " + context.getCurrentTemplateName()
+ " [" + this.getLine() + "," + this.getColumn() + "]");
return false;
}
return true;
}
private String getRoot()
{
Token t = getFirstToken();
/*
* we have a special case where something like
* $(\\)*!, where the user want's to see something
* like $!blargh in the output, but the ! prevents it from showing.
* I think that at this point, this isn't a reference.
*/
/* so, see if we have "\\!" */
int slashbang = t.image.indexOf("\\!");
if ( slashbang != -1 )
{
/*
* lets do all the work here. I would argue that if this occurrs, it's
* not a reference at all, so preceeding \ characters in front of the $
* are just schmoo. So we just do the escape processing trick (even | odd)
* and move on. This kind of breaks the rule pattern of $ and # but '!' really
* tosses a wrench into things.
*/
/*
* count the escapes : even # -> not escaped, odd -> escaped
*/
int i = 0;
int len = t.image.length();
i = t.image.indexOf('$');
if (i == -1)
{
/* yikes! */
rsvc.error("ASTReference.getRoot() : internal error : no $ found for slashbang.");
computableReference = false;
nullString = t.image;
return nullString;
}
while( i < len && t.image.charAt(i) != '\\')
i++;
/* ok, i is the first \ char */
int start = i;
int count = 0;
while( i < len && t.image.charAt(i++) == '\\' )
count++;
/*
* now construct the output string. We really don't care about leading
* slashes as this is not a reference. It's quasi-schmoo
*/
nullString = t.image.substring(0,start); // prefix up to the first
nullString += t.image.substring(start, start + count-1 ); // get the slashes
nullString += t.image.substring(start+count); // and the rest, including the
/*
* this isn't a valid reference, so lets short circuit the value and set calcs
*/
computableReference = false;
return nullString;
}
/*
* we need to see if this reference is escaped. if so
* we will clean off the leading \'s and let the
* regular behavior determine if we should output this
* as \$foo or $foo later on in render(). Lazyness..
*/
escaped = false;
if ( t.image.startsWith("\\"))
{
/*
* count the escapes : even # -> not escaped, odd -> escaped
*/
int i = 0;
int len = t.image.length();
while( i < len && t.image.charAt(i) == '\\' )
i++;
if ( (i % 2) != 0 )
escaped = true;
if (i > 0)
escPrefix = t.image.substring(0, i / 2 );
t.image = t.image.substring(i);
}
/*
* Look for preceeding stuff like '#' and '$'
* and snip it off, except for the
* last $
*/
int loc1 = t.image.lastIndexOf('$');
/*
* if we have extra stuff, loc > 0
* ex. '#$foo' so attach that to
* the prefix.
*/
if( loc1 > 0)
{
morePrefix = morePrefix + t.image.substring(0, loc1);
t.image = t.image.substring(loc1);
}
/*
* Now it should be clean. Get the literal in case this reference
* isn't backed by the context at runtime, and then figure out what
* we are working with.
*/
nullString = literal();
if (t.image.startsWith("$!"))
{
referenceType = QUIET_REFERENCE;
/*
* only if we aren't escaped do we want to null the output
*/
if (!escaped)
nullString = "";
if (t.image.startsWith("$!{"))
{
/*
* ex : $!{provider.Title}
*/
return t.next.image;
}
else
{
/*
* ex : $!provider.Title
*/
return t.image.substring(2);
}
}
else if (t.image.equals("${"))
{
/*
* ex : ${provider.Title}
*/
referenceType = FORMAL_REFERENCE;
return t.next.image;
}
else if ( t.image.startsWith("$") )
{
/*
* just nip off the '$' so we have
* the root
*/
referenceType = NORMAL_REFERENCE;
return t.image.substring(1);
}
else
{
/*
* this is a 'RUNT', which can happen in certain circumstances where
* the parser is fooled into believeing that an IDENTIFIER is a real
* reference. Another 'dreaded' MORE hack :).
*/
referenceType = RUNT;
return t.image;
}
}
public Object getVariableValue(Context context, String variable)
{
return context.get(variable);
}
/**
* Routine to allow the literal representation to be
* externally overridden. Used now in the VM system
* to override a reference in a VM tree with the
* literal of the calling arg to make it work nicely
* when calling arg is null. It seems a bit much, but
* does keep things consistant.
*
* Note, you can only set the literal once...
*
* @param literal String to render to when null
*/
public void setLiteral( String literal )
{
/*
* do only once
*/
if( this.literal == null)
this.literal = literal;
}
/**
* Override of the SimpleNode method literal()
* Returns the literal representation of the
* node. Should be something like
* $<token>.
*/
public String literal()
{
if (literal != null)
return literal;
return super.literal();
}
}