org.apache.commons.jexl.parser
Class ASTArrayAccess

java.lang.Object
  org.apache.commons.jexl.parser.SimpleNode
      org.apache.commons.jexl.parser.ASTArrayAccess

All Implemented Interfaces:

Node

public class ASTArrayAccess
extends SimpleNode

Like an ASTIdentifier, but with array access allowed. $foo[2]

Version:

$Id: ASTArrayAccess.java 398180 2006-04-29 15:40:35Z dion $

Author:

Geir Magnusson Jr.

Field Summary

private static Info

DUMMY dummy velocity info.

Fields inherited from class org.apache.commons.jexl.parser.SimpleNode

children, id, parent, parser

Constructor Summary

ASTArrayAccess(int id)
Create the node given an id.

ASTArrayAccess(Parser p, int id)
Create a node with the given parser and id.

Method Summary

static java.lang.Object	evaluateExpr(java.lang.Object o, java.lang.Object loc) Evaluate the Array expression 'loc' on the given object, o.
java.lang.Object	execute(java.lang.Object obj, JexlContext jc) evaluate array access upon a base object.
java.lang.String	getIdentifierString() Gets the variable name piece of the expression.
java.lang.Object	jjtAccept(ParserVisitor visitor, java.lang.Object data) Accept the visitor.
java.lang.Object	value(JexlContext jc) Gets the value of this node.

Methods inherited from class org.apache.commons.jexl.parser.SimpleNode

childrenAccept, dump, interpret, jjtAddChild, jjtClose, jjtGetChild, jjtGetNumChildren, jjtGetParent, jjtOpen, jjtSetParent, setValue, toString, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DUMMY

private static final Info DUMMY

dummy velocity info.

Constructor Detail

ASTArrayAccess

public ASTArrayAccess(int id)

Create the node given an id.

Parameters:

id - node id.

ASTArrayAccess

public ASTArrayAccess(Parser p,
                      int id)

Create a node with the given parser and id.

Parameters:

p - a parser.

id - node id.

Method Detail

jjtAccept

public java.lang.Object jjtAccept(ParserVisitor visitor,
                                  java.lang.Object data)

Accept the visitor.

Specified by:

jjtAccept in interface Node

Overrides:

jjtAccept in class SimpleNode

Parameters:

visitor - a ParserVisitor.

data - data to be passed along to the visitor.

Returns:

the value from visiting.

See Also:

ParserVisitor.visit(org.apache.commons.jexl.parser.SimpleNode, java.lang.Object)

execute

public java.lang.Object execute(java.lang.Object obj,
                                JexlContext jc)
                         throws java.lang.Exception

evaluate array access upon a base object. foo.bar[2] makes me rethink the array operator :)

Overrides:

execute in class SimpleNode

Parameters:

jc - the JexlContext to evaluate against.

obj - not used.

Returns:

the value of the array expression.

Throws:

java.lang.Exception - on any error

value

public java.lang.Object value(JexlContext jc)
                       throws java.lang.Exception

Gets the value of this node.

Overrides:

value in class SimpleNode

Parameters:

jc - the context to retrieve values from.

Returns:

the value of the node.

Throws:

java.lang.Exception - when evaluating the operands fails.

evaluateExpr

public static java.lang.Object evaluateExpr(java.lang.Object o,
                                            java.lang.Object loc)
                                     throws java.lang.Exception

Evaluate the Array expression 'loc' on the given object, o. e.g. in 'a[2]', 2 is 'loc' and a is 'o'. If o or loc are null, null is returned. If o is a Map, o.get(loc) is returned. If o is a List, o.get(loc) is returned. loc must resolve to an int value. If o is an Array, o[loc] is returned. loc must resolve to an int value. Otherwise loc is treated as a bean property of o.

Parameters:

o - an object to be accessed using the array operator or '.' operator.

loc - the index of the object to be returned.

Returns:

the resulting value.

Throws:

java.lang.Exception - on any error.

getIdentifierString

public java.lang.String getIdentifierString()

Gets the variable name piece of the expression.

Returns:

a String of the identifer.

See Also:

ASTIdentifier.getIdentifierString().