/*****************************************************************************
* *
* This file is part of the BeanShell Java Scripting distribution. *
* Documentation and updates may be found at http://www.beanshell.org/ *
* *
* Sun Public License Notice: *
* *
* The contents of this file are subject to the Sun Public License Version *
* 1.0 (the "License"); you may not use this file except in compliance with *
* the License. A copy of the License is available at http://www.sun.com *
* *
* The Original Code is BeanShell. The Initial Developer of the Original *
* Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
* (C) 2000. All Rights Reserved. *
* *
* GNU Public License Notice: *
* *
* Alternatively, the contents of this file may be used under the terms of *
* the GNU Lesser General Public License (the "LGPL"), in which case the *
* provisions of LGPL are applicable instead of those above. If you wish to *
* allow use of your version of this file only under the terms of the LGPL *
* and not to allow others to use your version of this file under the SPL, *
* indicate your decision by deleting the provisions above and replace *
* them with the notice and other provisions required by the LGPL. If you *
* do not delete the provisions above, a recipient may use your version of *
* this file under either the SPL or the LGPL. *
* *
* Patrick Niemeyer (pat@pat.net) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
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>
*/
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;
/**
@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).
*/
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.
*/
LHS(
Field field )
{
type =
FIELD;
this.
object = null;
this.
field =
field;
}
/**
Object field LHS Constructor.
*/
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.
*/
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.
*/
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 )
{
// return the raw type here... we don't know what it's supposed
// to be...
CollectionManager cm =
CollectionManager.
getCollectionManager();
if (
cm.
isMap(
object ) )
return
cm.
getFromMap(
object/*map*/,
propName );
else
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 {
// This should probably be in Reflect.java
ReflectManager.
RMSetAccessible(
field );
field.
set(
object,
Primitive.
unwrap(
val));
return
val;
}
catch(
NullPointerException e) {
throw new
UtilEvalError(
"LHS ("+
field.
getName()+") not a static field.");
}
catch(
IllegalAccessException e2) {
throw new
UtilEvalError(
"LHS ("+
field.
getName()+") can't access field: "+
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 )
{
CollectionManager cm =
CollectionManager.
getCollectionManager();
if (
cm.
isMap(
object ) )
cm.
putInMap(
object/*map*/,
propName,
Primitive.
unwrap(
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(): "");
}
}