org.apache.commons.ognl
Interface Node

All Superinterfaces:

JavaSource

All Known Implementing Classes:

ASTAnd, ASTChain, ASTConst, ASTCtor, ASTInstanceof, ASTList, ASTMethod, ASTOr, ASTProperty, ASTRootVarRef, ASTSequence, ASTStaticField, ASTStaticMethod, ASTThisVarRef, ASTVarRef, BooleanExpression, ComparisonExpression, ExpressionNode, NumericExpression, SimpleNode

public interface Node
extends JavaSource

JJTree interface for AST nodes, as modified to handle the OGNL operations getValue and setValue. JJTree's original comment: All AST nodes must implement this interface. It provides basic machinery for constructing the parent and child relationships between nodes.

Author:

Luke Blanshard (blanshlu@netscape.net), Drew Davidson (drew@ognl.org)

jjtOpen

void jjtOpen()

This method is called after the node has been made the current node. It indicates that child nodes can now be added to it.

jjtClose

void jjtClose()

This method is called after all the child nodes have been added.

jjtSetParent

void jjtSetParent(Node n)

This pair of methods are used to inform the node of its parent.

jjtGetParent

Node jjtGetParent()

jjtAddChild

void jjtAddChild(Node n,
                 int i)

This method tells the node to add its argument to the node's list of children.

jjtGetChild

Node jjtGetChild(int i)

This method returns a child node. The children are numbered from zero, left to right.

jjtGetNumChildren

int jjtGetNumChildren()

Return the number of children the node has.

getValue

Object getValue(OgnlContext context,
                Object source)
                throws OgnlException

Extracts the value from the given source object that is appropriate for this node within the given context.

Throws:

OgnlException

setValue

void setValue(OgnlContext context,
              Object target,
              Object value)
              throws OgnlException

Sets the given value in the given target as appropriate for this node within the given context.

Throws:

OgnlException

getAccessor

ExpressionAccessor getAccessor()

Gets the compiled bytecode enhanced expression accessor for getting/setting values.

Returns:

The accessor for this node, or null if none has been compiled for it.

setAccessor

void setAccessor(ExpressionAccessor accessor)

Sets a new compiled accessor for this node expression.

Parameters:

accessor - The compiled representation of this node.

accept

<R,P> R accept(NodeVisitor<? extends R,? super P> visitor,
               P data)
         throws OgnlException

Supports the Visitor pattern. The method which corresponds to the runtime type of this Node will be called.

Type Parameters:

R - The return type of the visitor.visit method.

P - The type of the second parameter type.

Parameters:

visitor - The visitor to accept.

data - The second parameter to pass through to visitor.visit

Returns:

the value returned by visitor.visit

Throws:

NullPointerException - if visitor is null

RuntimeException - if visitor.visit throws an exception.

OgnlException