/**
*
* This file is a part of ZOOLA - an extensible BeanShell implementation.
* Zoola is based on original BeanShell code created by Pat Niemeyer.
*
* Original BeanShell code is Copyright (C) 2000 Pat Niemeyer <pat@pat.net>.
*
* New portions are Copyright 2012 Rafal Lewczuk <rafal.lewczuk@jitlogic.com>
*
* This is free software. You can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* This software is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with ZOOLA. If not, see <http://www.gnu.org/licenses/>.
*
*/
package bsh;
import java.lang.reflect.Field;
import java.util.Hashtable;
/**
An LHS is a wrapper for an variable, field, or property. It ordinarily
holds the "left hand side" of an assignment and may be either resolved to
a value or assigned a value.
<p>
There is one special case here termed METHOD_EVAL where the LHS is used
in an intermediate evaluation of a chain of suffixes and wraps a method
invocation. In this case it may only be resolved to a value and cannot be
assigned. (You can't assign a value to the result of a method call e.g.
"foo() = 5;").
<p>
*/
public class LHS implements ParserConstants, java.io.Serializable
{
NameSpace nameSpace;
/** The assignment should be to a local variable */
boolean localVar;
/**
Identifiers for the various types of LHS.
*/
static final int
VARIABLE = 0,
FIELD = 1,
PROPERTY = 2,
INDEX = 3,
METHOD_EVAL = 4;
int type;
String varName;
String propName;
Field field;
Object object;
int index;
/**
Variable LHS constructor.
*/
public LHS( NameSpace nameSpace, String varName )
{
throw new Error("namespace lhs");
/*
type = VARIABLE;
this.varName = varName;
this.nameSpace = nameSpace;
*/
}
/**
@param localVar if true the variable is set directly in the This
reference's local scope. If false recursion to look for the variable
definition in parent's scope is allowed. (e.g. the default case for
undefined vars going to global).
*/
public LHS( NameSpace nameSpace, String varName, boolean localVar )
{
type = VARIABLE;
this.localVar = localVar;
this.varName = varName;
this.nameSpace = nameSpace;
}
/**
Static field LHS Constructor.
This simply calls Object field constructor with null object.
*/
public LHS( Field field )
{
type = FIELD;
this.object = null;
this.field = field;
}
/**
Object field LHS Constructor.
*/
public LHS( Object object, Field field )
{
if ( object == null)
throw new NullPointerException("constructed empty LHS");
type = FIELD;
this.object = object;
this.field = field;
}
/**
Object property LHS Constructor.
*/
public LHS( Object object, String propName )
{
if(object == null)
throw new NullPointerException("constructed empty LHS");
type = PROPERTY;
this.object = object;
this.propName = propName;
}
/**
Array index LHS Constructor.
*/
public LHS( Object array, int index )
{
if(array == null)
throw new NullPointerException("constructed empty LHS");
type = INDEX;
this.object = array;
this.index = index;
}
public Object getValue() throws UtilEvalError
{
if ( type == VARIABLE )
return nameSpace.getVariable( varName );
if (type == FIELD)
try {
Object o = field.get( object );
return Primitive.wrap( o, field.getType() );
} catch(IllegalAccessException e2) {
throw new UtilEvalError("Can't read field: " + field);
}
if ( type == PROPERTY )
try {
return Reflect.getObjectProperty(object, propName);
}
catch(ReflectError e) {
Interpreter.debug(e.getMessage());
throw new UtilEvalError("No such property: " + propName);
}
if ( type == INDEX )
try {
return Reflect.getIndex(object, index);
}
catch(Exception e) {
throw new UtilEvalError("Array access: " + e);
}
throw new InterpreterError("LHS type");
}
/**
Assign a value to the LHS.
*/
public Object assign( Object val, boolean strictJava )
throws UtilEvalError
{
if ( type == VARIABLE )
{
// Set the variable in namespace according to localVar flag
if ( localVar )
nameSpace.setLocalVariable( varName, val, strictJava );
else
nameSpace.setVariable( varName, val, strictJava );
} else
if ( type == FIELD )
{
try {
Object fieldVal = val instanceof Primitive ?
((Primitive)val).getValue() : val;
// This should probably be in Reflect.java
field.setAccessible(true);
field.set( object, fieldVal );
return val;
}
catch( NullPointerException e) {
throw new UtilEvalError(
"LHS ("+field.getName()+") not a static field.",e);
}
catch( IllegalAccessException e2) {
throw new UtilEvalError(
"LHS ("+field.getName()+") can't access field: "+e2,e2);
}
catch( IllegalArgumentException e3)
{
String type = val instanceof Primitive ?
((Primitive)val).getType().getName()
: val.getClass().getName();
throw new UtilEvalError(
"Argument type mismatch. " + (val == null ? "null" : type )
+ " not assignable to field "+field.getName());
}
}
else
if ( type == PROPERTY )
{
/*
if ( object instanceof Hashtable )
((Hashtable)object).put(propName, val);
*/
CollectionManager cm = CollectionManager.getCollectionManager();
if ( cm.isMap( object ) )
cm.putInMap( object/*map*/, propName, val );
else
try {
Reflect.setObjectProperty(object, propName, val);
}
catch(ReflectError e) {
Interpreter.debug("Assignment: " + e.getMessage());
throw new UtilEvalError("No such property: " + propName);
}
} else
if ( type == INDEX )
try {
Reflect.setIndex(object, index, val);
} catch ( UtilTargetError e1 ) { // pass along target error
throw e1;
} catch ( Exception e ) {
throw new UtilEvalError("Assignment: " + e.getMessage());
}
else
throw new InterpreterError("unknown lhs");
return val;
}
public String toString() {
return "LHS: "
+((field!=null)? "field = "+field.toString():"")
+(varName!=null ? " varName = "+varName: "")
+(nameSpace!=null ? " nameSpace = "+nameSpace.toString(): "");
}
}