/*
 * Copyright 2001-2004 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.axis.handlers;

import org.apache.axis.AxisFault;
import org.apache.axis.Handler;
import org.apache.axis.MessageContext;
import org.apache.axis.components.logger.LogFactory;
import org.apache.axis.utils.LockableHashtable;
import org.apache.commons.logging.Log;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.xml.namespace.QName;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.List;


/** <code>BasicHandler</code> is a utility class which implements simple
 * property setting/getting behavior, and stubs out a lot of the Handler
 * methods.  Extend this class to make writing your Handlers easier, and
 * then override what you need to.
 *
 * @author Glen Daniels (gdaniels@allaire.com)
 * @author Doug Davis (dug@us.ibm.com
 */
public abstract class BasicHandler implements Handler {
    private static Log log =
        LogFactory.getLog(BasicHandler.class.getName());

    protected boolean makeLockable = false;
    protected Hashtable options;
    protected String name;


    /**
     * Should this Handler use a LockableHashtable for options?
     * Default is 'false'.
     */
    protected void setOptionsLockable(boolean makeLockable) {
        this.makeLockable = makeLockable;
    }
    
    protected void initHashtable()
    {
        if (makeLockable) {
            options = new LockableHashtable();
        } else {
            options = new Hashtable();
        }
    }

    /**
     * Stubbed-out methods.  Override in your child class to implement
     * any real behavior.  Note that there is NOT a stub for invoke(), since
     * we require any Handler derivative to implement that.
     */


    public void init()
    {
    }

    public void cleanup()
    {
    }

    public boolean canHandleBlock(QName qname)
    {
        return false;
    }

    public void onFault(MessageContext msgContext)
    {
    }
    
    /**
     * Set the given option (name/value) in this handler's bag of options
     */
    public void setOption(String name, Object value) {
        if ( options == null ) initHashtable();
        options.put( name, value );
    }

    /**
     * Set a default value for the given option:
     * if the option is not already set, then set it.
     * if the option is already set, then do not set it.
     * <p>
     * If this is called multiple times, the first with a non-null value
     * if 'value' will set the default, remaining calls will be ignored.
     * <p>
     * Returns true if value set (by this call), otherwise false;
     */
    public boolean setOptionDefault(String name, Object value) {
        boolean val = (options == null  || options.get(name) == null) && value != null;
        if (val) {
            setOption(name, value);
        }
        return val;
    }
    
    /**
     * Returns the option corresponding to the 'name' given
     */
    public Object getOption(String name) {
        if ( options == null ) return( null );
        return( options.get(name) );
    }

    /**
     * Return the entire list of options
     */
    public Hashtable getOptions() {
        return( options );
    }

    public void setOptions(Hashtable opts) {
        options = opts;
    }

    /**
     * Set the name (i.e. registry key) of this Handler
     */
    public void setName(String name)
    {
        this.name = name;
    }

    /**
     * Return the name (i.e. registry key) for this Handler
     */
    public String getName()
    {
        return name;
    }

    public Element getDeploymentData(Document doc) {
        log.debug("Enter: BasicHandler::getDeploymentData");

        Element  root = doc.createElementNS("", "handler");

        root.setAttribute( "class", this.getClass().getName() );
        options = this.getOptions();
        if ( options != null ) {
            Enumeration e = options.keys();
            while ( e.hasMoreElements() ) {
                String k = (String) e.nextElement();
                Object v = options.get(k);
                Element e1 = doc.createElementNS("", "option" );
                e1.setAttribute( "name", k );
                e1.setAttribute( "value", v.toString() );
                root.appendChild( e1 );
            }
        }
        log.debug("Exit: BasicHandler::getDeploymentData");
        return( root );
    }

    public void generateWSDL(MessageContext msgContext) throws AxisFault
    {
    }

    /**
     * Return a list of QNames which this Handler understands.  By returning
     * a particular QName here, we are committing to fulfilling any contracts
     * defined in the specification of the SOAP header with that QName.
     */
    public List getUnderstoodHeaders() {
        return null;
    }
}