defaultpathexpr.java

XML的解析、编译、查询等技术的JAVA源代码。

/*
 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultPathExpr.java,v 1.16 2006/11/30 18:49:26 elharo Exp $
 * $Revision: 1.16 $
 * $Date: 2006/11/30 18:49:26 $
 *
 * ====================================================================
 *
 * Copyright 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:
 * 
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 
 *   * Neither the name of the Jaxen Project nor the names of its
 *     contributors may be used to endorse or promote products derived 
 *     from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS 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 COPYRIGHT OWNER
 * OR 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 <[e-mail]> and
 * James Strachan <[e-mail]>.  For more information on the
 * Jaxen Project, please see <http://www.jaxen.org/>.
 *
 * $Id: DefaultPathExpr.java,v 1.16 2006/11/30 18:49:26 elharo Exp $
 */

package org.jaxen.expr;


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


class DefaultPathExpr extends DefaultExpr implements PathExpr {

    private static final long serialVersionUID = -6593934674727004281L;
    private Expr filterExpr;
    private LocationPath locationPath;

    DefaultPathExpr(Expr filterExpr,
                           LocationPath locationPath) {
        this.filterExpr = filterExpr;
        this.locationPath = locationPath;
    }

    public Expr getFilterExpr() {
        return this.filterExpr;
    }


    public void setFilterExpr(Expr filterExpr) {
        this.filterExpr = filterExpr;
    }


    public LocationPath getLocationPath() {
        return this.locationPath;
    }


    public String toString() {
        if (getLocationPath() != null) {
            return "[(DefaultPathExpr): " + getFilterExpr() + ", " + getLocationPath() + "]";
        }

        return "[(DefaultPathExpr): " + getFilterExpr() + "]";
    }


    public String getText() {
        StringBuffer buf = new StringBuffer();

        if (getFilterExpr() != null) {
            buf.append(getFilterExpr().getText());
        }

        if (getLocationPath() != null) {
            if (!getLocationPath().getSteps().isEmpty()) buf.append("/");
            buf.append(getLocationPath().getText());
        }

        return buf.toString();
    }


    public Expr simplify() {
        if (getFilterExpr() != null) {
            setFilterExpr(getFilterExpr().simplify());
        }

        if (getLocationPath() != null) {
            getLocationPath().simplify();
        }

        if (getFilterExpr() == null && getLocationPath() == null) {
            return null;
        }


        if (getLocationPath() == null) {
            return getFilterExpr();
        }

        if (getFilterExpr() == null) {
            return getLocationPath();
        }

        return this;
    }

    public Object evaluate(Context context) throws JaxenException {
        Object results = null;
        Context pathContext = null;
        if (getFilterExpr() != null) {
            results = getFilterExpr().evaluate(context);
            pathContext = new Context(context.getContextSupport());
            pathContext.setNodeSet(convertToList(results));
        }
        if (getLocationPath() != null) {
            return getLocationPath().evaluate(pathContext);
        }
        return results;
    }
    
}