/*****************************************************************************
* *
* 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 ([email protected]) *
* 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.getVariableOrProperty( varName, null );
// 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.setLocalVariableOrProperty( varName, val, strictJava );
else
nameSpace.setVariableOrProperty( 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(): "");
}
}
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