org.zkoss.bind.xel.zel.PathELResolver Maven / Gradle / Ivy

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/* PathResolver.java

	Purpose:
		
	Description:
		
	History:
		Sep 8, 2011 9:05:13 AM, Created by henrichen

Copyright (C) 2011 Potix Corporation. All Rights Reserved.
*/

package org.zkoss.bind.xel.zel;

import java.beans.FeatureDescriptor;
import java.util.Iterator;
import java.util.Stack;

import org.zkoss.bind.impl.Path;
import org.zkoss.lang.Objects;
import org.zkoss.zel.ELContext;
import org.zkoss.zel.ELException;
import org.zkoss.zel.ELResolver;
import org.zkoss.zel.PropertyNotFoundException;
import org.zkoss.zel.PropertyNotWritableException;
import org.zkoss.zel.impl.parser.AstIdentifier;
import org.zkoss.zel.impl.parser.Node;

/**
 * Handle dot series path when evaluating expression.
 * @author henrichen
 * @since 6.0.0
 */
public class PathELResolver extends ELResolver {
	private Stack _numOfKids = new Stack();
	private Stack _paths = new Stack();
	
	private String toNodeString(ELContext ctx) {
		final Node node0 = (Node) ctx.getContext(Node.class);
		return BindELContext.toNodeString(node0, new StringBuffer());
	}
	
	
	public Object getValue(ELContext ctx, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
        if (ctx == null) {
            throw new NullPointerException();
        }
        if (base == null) { //init
        	final Integer numOfKids = (Integer) ctx.getContext(AstIdentifier.class); //Number of siblings of AstIdentifier
			_numOfKids.push(numOfKids);
			_paths.push(new Path());
        }
        Integer numOfKids = _numOfKids.pop();
        Path path = _paths.pop();
        
    	//maintain the number of kids
    	int nums = numOfKids.intValue() - 1;
    	numOfKids = new Integer(nums);
    	ctx.putContext(Integer.class, numOfKids);

    	//maintain the form path field
    	path.add(toNodeString(ctx), Objects.toString(property));
    	ctx.putContext(Path.class, path);

        if (nums > 0) { //still more property
        	_numOfKids.push(numOfKids);
        	_paths.push(path);
        }
        return null;
	}

	
	public Class getType(ELContext ctx, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
        if (ctx == null) {
            throw new NullPointerException();
        }

        Integer numOfKids = _numOfKids.pop();
        Path path = _paths.pop();
        
    	//maintain the number of kids
    	int nums = numOfKids.intValue() - 1;
    	numOfKids = new Integer(nums);
    	ctx.putContext(Integer.class, numOfKids);

    	//maintain the form path field
    	path.add(toNodeString(ctx), Objects.toString(property));
    	ctx.putContext(Path.class, path);
    	
    	return null;

	}

	
	public void setValue(ELContext ctx, Object base, Object property,
			Object value) throws NullPointerException,
			PropertyNotFoundException, PropertyNotWritableException,
			ELException {
        if (ctx == null) {
            throw new NullPointerException();
        }
		
        //#getType() will maintain number of kids and path field, just let go
	}

	
	public boolean isReadOnly(ELContext context, Object base, Object property)
			throws NullPointerException, PropertyNotFoundException, ELException {
		return true;
	}

	
	public Iterator getFeatureDescriptors(ELContext context,
			Object base) {
		return null;
	}

	
	public Class getCommonPropertyType(ELContext context, Object base) {
		return null;
	}
}