/*****************************************************************************
* *
* 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;
class
BSHSwitchStatement
extends
SimpleNode
implements
ParserConstants
{
public
BSHSwitchStatement(int
id) { super(
id); }
public
Object eval(
CallStack callstack,
Interpreter interpreter )
throws
EvalError
{
int
numchild =
jjtGetNumChildren();
int
child = 0;
SimpleNode switchExp = ((
SimpleNode)
jjtGetChild(
child++));
Object switchVal =
switchExp.
eval(
callstack,
interpreter );
/*
Note: this could be made clearer by adding an inner class for the
cases and an object context for the child traversal.
*/
// first label
BSHSwitchLabel label;
Object node;
ReturnControl returnControl=null;
// get the first label
if (
child >=
numchild )
throw new
EvalError("Empty switch statement.", this,
callstack );
label = ((
BSHSwitchLabel)
jjtGetChild(
child++));
// while more labels or blocks and haven't hit return control
while (
child <
numchild &&
returnControl == null )
{
// if label is default or equals switchVal
if (
label.
isDefault
||
primitiveEquals(
switchVal,
label.
eval(
callstack,
interpreter ),
callstack,
switchExp )
)
{
// execute nodes, skipping labels, until a break or return
while (
child <
numchild )
{
node =
jjtGetChild(
child++);
if (
node instanceof
BSHSwitchLabel )
continue;
// eval it
Object value =
((
SimpleNode)
node).
eval(
callstack,
interpreter );
// should check to disallow continue here?
if (
value instanceof
ReturnControl ) {
returnControl = (
ReturnControl)
value;
break;
}
}
} else
{
// skip nodes until next label
while (
child <
numchild )
{
node =
jjtGetChild(
child++);
if (
node instanceof
BSHSwitchLabel ) {
label = (
BSHSwitchLabel)
node;
break;
}
}
}
}
if (
returnControl != null &&
returnControl.
kind ==
RETURN )
return
returnControl;
else
return
Primitive.
VOID;
}
/**
Helper method for testing equals on two primitive or boxable objects.
yuck: factor this out into Primitive.java
*/
private boolean
primitiveEquals(
Object switchVal,
Object targetVal,
CallStack callstack,
SimpleNode switchExp )
throws
EvalError
{
if (
switchVal instanceof
Primitive ||
targetVal instanceof
Primitive )
try {
// binaryOperation can return Primitive or wrapper type
Object result =
Primitive.
binaryOperation(
switchVal,
targetVal,
ParserConstants.
EQ );
result =
Primitive.
unwrap(
result );
return
result.
equals(
Boolean.
TRUE );
} catch (
UtilEvalError e ) {
throw
e.
toEvalError(
"Switch value: "+
switchExp.
getText()+": ",
this,
callstack );
}
else
return
switchVal.
equals(
targetVal );
}
}