jaxen/expr/DefaultFilterExpr.java

/*
 * $Header: /cvsroot/jaxen/jaxen/src/java/main/org/jaxen/expr/DefaultFilterExpr.java,v 1.8 2002/04/26 17:17:34 jstrachan Exp $
 * $Revision: 1.8 $
 * $Date: 2002/04/26 17:17:34 $
 *
 * ====================================================================
 *
 * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the disclaimer that follows
 *    these conditions in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. The name "Jaxen" must not be used to endorse or promote products
 *    derived from this software without prior written permission.  For
 *    written permission, please contact license@jaxen.org.
 *
 * 4. Products derived from this software may not be called "Jaxen", nor
 *    may "Jaxen" appear in their name, without prior written permission
 *    from the Jaxen Project Management (pm@jaxen.org).
 *
 * In addition, we request (but do not require) that you include in the
 * end-user documentation provided with the redistribution and/or in the
 * software itself an acknowledgement equivalent to the following:
 *     "This product includes software developed by the
 *      Jaxen Project (http://www.jaxen.org/)."
 * Alternatively, the acknowledgment may be graphical using the logos
 * available at http://www.jaxen.org/
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * ====================================================================
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Jaxen Project and was originally
 * created by bob mcwhirter <bob@werken.com> and
 * James Strachan <jstrachan@apache.org>.  For more information on the
 * Jaxen Project, please see <http://www.jaxen.org/>.
 *
 * $Id: DefaultFilterExpr.java,v 1.8 2002/04/26 17:17:34 jstrachan Exp $
 */


package org.jaxen.expr;

import org.jaxen.Context;
import org.jaxen.JaxenException;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Set;
import java.util.List;

public class DefaultFilterExpr extends DefaultExpr implements FilterExpr, Predicated
{
    private Expr expr;
    private PredicateSet predicates;

    public DefaultFilterExpr()
    {
        this.predicates = new PredicateSet();
    }

    public DefaultFilterExpr(Expr expr)
    {
        this.expr       = expr;
        this.predicates = new PredicateSet();
    }

    public void addPredicate(Predicate predicate)
    {
        this.predicates.addPredicate( predicate );
    }

    public List getPredicates()
    {
        return this.predicates.getPredicates();
    }

    public PredicateSet getPredicateSet()
    {
        return this.predicates;
    }

    public Expr getExpr()
    {
        return this.expr;
    }

    public String toString()
    {
        return "[(DefaultFilterExpr): expr: " + expr + " predicates: " + predicates + " ]";
    }

    public String getText()
    {
        String text = "";
        if ( this.expr != null )
        {
            text = this.expr.getText();
        }
        text += predicates.getText();
        return text;
    }

    public Expr simplify()
    {
        this.predicates.simplify();

        if ( this.expr != null )
        {
            this.expr = this.expr.simplify();
        }

        if ( this.predicates.getPredicates().size() == 0 )
        {
            return getExpr();
        }

        return this;
    }

    /** Returns true if the current filter matches at least one of the context nodes
     */
    public boolean asBoolean(Context context) throws JaxenException
    {
        Object results = null;
        if ( expr != null )
        {
            results = expr.evaluate( context );
        }
        else
        {
            ArrayList list = new ArrayList(1);
            list.addAll( context.getNodeSet() );
            results = list;
        }

        if ( results instanceof Boolean )
        {
            Boolean b = (Boolean) results;
            return b.booleanValue();
        }
        if ( results instanceof List )
        {
            return getPredicateSet().evaluateAsBoolean(
                (List) results, context.getContextSupport()
            );
        }

        return false;
    }

    public Object evaluate(Context context) throws JaxenException
    {
        Object results = getExpr().evaluate( context );

        if ( results instanceof List )
        {
            List newresults = getPredicateSet().evaluatePredicates( (List) results,
								    context.getContextSupport() );
	    results = newresults;
        }

        return results;
    }
}