/*
 * 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.sshd.common.session;

import org.apache.sshd.common.channel.exception.SshChannelNotFoundException;

/**
 * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
 */
public interface UnknownChannelReferenceHandlerManager {
    /**
     * @return The {@link UnknownChannelReferenceHandlerManager} to use - if {@code null} then any reference to unknown
     *         channel causes an {@link SshChannelNotFoundException}
     */
    UnknownChannelReferenceHandler getUnknownChannelReferenceHandler();

    /**
     * @param handler The {@link UnknownChannelReferenceHandlerManager} to use - if {@code null} then any reference to
     *                unknown channel causes an {@link SshChannelNotFoundException}
     */
    void setUnknownChannelReferenceHandler(UnknownChannelReferenceHandler handler);

    /**
     * Check if current manager has a specific handler set for it - if not, try and resolve one from the
     * &quot;parent&quot; container (if any)
     *
     * @return The resolved handler instance
     */
    UnknownChannelReferenceHandler resolveUnknownChannelReferenceHandler();
}
