node.java

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//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
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//  DAMAGE.
//--------------------------------------------------------------------------
package ognl;

/**
   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 ([e-mail])
   @author Drew Davidson ([e-mail])
*/
public interface Node
{

    /** This method is called after the node has been made the current
        node.  It indicates that child nodes can now be added to it. */
    public void jjtOpen();

    /** This method is called after all the child nodes have been
        added. */
    public void jjtClose();

    /** This pair of methods are used to inform the node of its
        parent. */
    public void jjtSetParent(Node n);
    public Node jjtGetParent();

    /** This method tells the node to add its argument to the node's
        list of children.  */
    public void jjtAddChild(Node n, int i);

    /** This method returns a child node.  The children are numbered
        from zero, left to right. */
    public Node jjtGetChild(int i);

    /** Return the number of children the node has. */
    public int jjtGetNumChildren();


// OGNL additions to Node:

    /**
     * Extracts the value from the given source object that is appropriate for this node
     * within the given context.
     */
    public Object getValue( OgnlContext context, Object source ) throws OgnlException;

    /**
     * Sets the given value in the given target as appropriate for this node within the
     * given context.
     */
    public void setValue( OgnlContext context, Object target, Object value ) throws OgnlException;
}