jaxws/src/share/classes/com/sun/xml/internal/bind/v2/runtime/unmarshaller/DefaultValueLoaderDecorator.java

/*
 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.xml.internal.bind.v2.runtime.unmarshaller;

import org.xml.sax.SAXException;

/**
 * Decorates another {@link Loader} by setting a default value.
 *
 * @author Kohsuke Kawaguchi
 */
public final class DefaultValueLoaderDecorator extends Loader {
    private final Loader l;
    private final String defaultValue;

    public DefaultValueLoaderDecorator(Loader l, String defaultValue) {
        this.l = l;
        this.defaultValue = defaultValue;
    }

    @Override
    public void startElement(UnmarshallingContext.State state, TagName ea) throws SAXException {
        // install the default value, but don't override the one given by the parent loader
        if(state.elementDefaultValue==null)
            state.elementDefaultValue = defaultValue;

        state.loader = l;
        l.startElement(state,ea);
    }
}