contrib/jcr-server/webdav/src/java/org/apache/jackrabbit/webdav/property/PropContainer.java

/*
 * Copyright 2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.property;

import org.apache.jackrabbit.webdav.DavConstants;
import org.apache.jackrabbit.webdav.xml.DomUtil;
import org.apache.jackrabbit.webdav.xml.XmlSerializable;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import java.util.Collection;
import java.util.Iterator;

/**
 * <code>PropContainer</code>...
 */
public abstract class PropContainer implements XmlSerializable, DavConstants {

    private static Logger log = Logger.getLogger(PropContainer.class);

    /**
     * Tries to add the specified object to the <code>PropContainer</code> and
     * returns a boolean indicating whether the content could be added to the
     * internal set/map.
     *
     * @param contentEntry
     * @return true if the object could be added; false otherwise
     */
    public abstract boolean addContent(Object contentEntry);

    /**
     * Returns true if the PropContainer does not yet contain any content elements.
     *
     * @return true if this container is empty.
     */
    public abstract boolean isEmpty();

    /**
     * Returns the number of property related content elements that are present
     * in this <code>PropContainer</code>.
     *
     * @return number of content elements
     */
    public abstract int getContentSize();

    /**
     * Returns the collection that contains all the content elements of this
     * <code>PropContainer</code>.
     *
     * @return collection representing the contents of this <code>PropContainer</code>.
     */
    public abstract Collection getContent();

    /**
     * Returns true if this <code>PropContainer</code> contains a content element
     * that matches the given <code>DavPropertyName</code>.
     *
     * @param name
     * @return true if any of the content elements (be it a DavProperty or a
     * DavPropertyName only) matches the given name.
     */
    public abstract boolean contains(DavPropertyName name);

    /**
     * Returns the xml representation of a property related set with the
     * following format:
     * <pre>
     * &lt;!ELEMENT prop (ANY) &gt;
     * where ANY consists of a list of elements each reflecting the xml
     * representation of the entries returned by {@link #getContent()}.
     * </pre>
     * 
     * @see XmlSerializable#toXml(Document)
     */
    public Element toXml(Document document) {
        Element prop = DomUtil.createElement(document, XML_PROP, NAMESPACE);
        Iterator it = getContent().iterator();
        while (it.hasNext()) {
            Object content = it.next();
            if (content instanceof XmlSerializable) {
                prop.appendChild(((XmlSerializable)content).toXml(document));
            } else {
                log.debug("Unexpected content in PropContainer: should be XmlSerializable.");
            }
        }
        return prop;
    }

}