/**
 * All rights reserved. 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.jivesoftware.smackx.packet;

import java.util.Collection;
import java.util.Collections;

import org.jivesoftware.smack.packet.PacketExtension;

/**
 * Extension representing a list of headers as specified in <a href="http://xmpp.org/extensions/xep-0131">Stanza Headers and Internet Metadata (SHIM)</a>
 *
 * @author Robin Collier
 * @see Header
 */
public class HeadersExtension implements PacketExtension {
    public static final String NAMESPACE = "http://jabber.org/protocol/shim";

    private Collection<Header> headers = Collections.EMPTY_LIST;

    public HeadersExtension(Collection<Header> headerList) {
        if (headerList != null)
            headers = headerList;
    }

    public Collection<Header> getHeaders() {
        return headers;
    }

    public String getElementName() {
        return "headers";
    }

    public String getNamespace() {
        return NAMESPACE;
    }

    public String toXML() {
        StringBuilder builder = new StringBuilder("<" + getElementName() + " xmlns='" + getNamespace() + "'>");

        for (Header header : headers) {
            builder.append(header.toXML());
        }
        builder.append("</" + getElementName() + '>');

        return builder.toString();
    }

}
