/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.directory.api.ldap.codec.actions.controls;


import org.apache.directory.api.asn1.DecoderException;
import org.apache.directory.api.asn1.ber.grammar.GrammarAction;
import org.apache.directory.api.asn1.ber.tlv.TLV;
import org.apache.directory.api.ldap.codec.api.LdapMessageContainer;
import org.apache.directory.api.ldap.codec.api.MessageDecorator;
import org.apache.directory.api.ldap.model.message.Message;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * The action used to initialize a control.
 * <pre>
 *         ... },
 *     controls       [0] Controls OPTIONAL }
 * </pre>
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 */
public class InitControls extends GrammarAction<LdapMessageContainer<MessageDecorator<? extends Message>>>
{
    /** The logger */
    private static final Logger LOG = LoggerFactory.getLogger( InitControls.class );

    /** Speedup for logs */
    private static final boolean IS_DEBUG = LOG.isDebugEnabled();


    /**
     * Instantiates a new controls init action.
     */
    public InitControls()
    {
        super( "Initialize a control" );
    }


    /**
     * {@inheritDoc}
     */
    public void action( LdapMessageContainer<MessageDecorator<? extends Message>> container ) throws DecoderException
    {
        TLV tlv = container.getCurrentTLV();
        int expectedLength = tlv.getLength();

        // The Length should be null
        if ( expectedLength == 0 )
        {
            LOG.error( "The length of controls must not be null" );

            // This will generate a PROTOCOL_ERROR
            throw new DecoderException( "The length of controls must not be null" );
        }

        if ( IS_DEBUG )
        {
            LOG.debug( "A new list of controls has been initialized" );
        }
    }
}