package org.eclipse.aether.util.listener;

/*
 * 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.
 */

import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

import org.eclipse.aether.AbstractRepositoryListener;
import org.eclipse.aether.RepositoryEvent;
import org.eclipse.aether.RepositoryListener;

A repository listener that delegates to zero or more other listeners (multicast). The list of target listeners is
thread-safe, i.e. target listeners can be added or removed by any thread at any time.
/**
 * A repository listener that delegates to zero or more other listeners (multicast). The list of target listeners is
 * thread-safe, i.e. target listeners can be added or removed by any thread at any time.
 */
public final class ChainedRepositoryListener
    extends AbstractRepositoryListener
{

    private final List<RepositoryListener> listeners = new CopyOnWriteArrayList<>();

    
Creates a new multicast listener that delegates to the specified listeners. In contrast to the constructor, this factory method will avoid creating an actual chained listener if one of the specified readers is actually null. 
Params:
listener1 – The first listener, may be null.
listener2 – The second listener, may be null.
Returns:
The chained listener or null if no listener was supplied./**
     * Creates a new multicast listener that delegates to the specified listeners. In contrast to the constructor, this
     * factory method will avoid creating an actual chained listener if one of the specified readers is actually
     * {@code null}.
     * 
     * @param listener1 The first listener, may be {@code null}.
     * @param listener2 The second listener, may be {@code null}.
     * @return The chained listener or {@code null} if no listener was supplied.
     */
    public static RepositoryListener newInstance( RepositoryListener listener1, RepositoryListener listener2 )
    {
        if ( listener1 == null )
        {
            return listener2;
        }
        else if ( listener2 == null )
        {
            return listener1;
        }
        return new ChainedRepositoryListener( listener1, listener2 );
    }

    
Creates a new multicast listener that delegates to the specified listeners.
Params:
listeners – The listeners to delegate to, may be null or empty./**
     * Creates a new multicast listener that delegates to the specified listeners.
     * 
     * @param listeners The listeners to delegate to, may be {@code null} or empty.
     */
    public ChainedRepositoryListener( RepositoryListener... listeners )
    {
        if ( listeners != null )
        {
            add( Arrays.asList( listeners ) );
        }
    }

    
Creates a new multicast listener that delegates to the specified listeners.
Params:
listeners – The listeners to delegate to, may be null or empty./**
     * Creates a new multicast listener that delegates to the specified listeners.
     * 
     * @param listeners The listeners to delegate to, may be {@code null} or empty.
     */
    public ChainedRepositoryListener( Collection<? extends RepositoryListener> listeners )
    {
        add( listeners );
    }

    
Adds the specified listeners to the end of the multicast chain.
Params:
listeners – The listeners to add, may be null or empty./**
     * Adds the specified listeners to the end of the multicast chain.
     * 
     * @param listeners The listeners to add, may be {@code null} or empty.
     */
    public void add( Collection<? extends RepositoryListener> listeners )
    {
        if ( listeners != null )
        {
            for ( RepositoryListener listener : listeners )
            {
                add( listener );
            }
        }
    }

    
Adds the specified listener to the end of the multicast chain.
Params:
listener – The listener to add, may be null./**
     * Adds the specified listener to the end of the multicast chain.
     * 
     * @param listener The listener to add, may be {@code null}.
     */
    public void add( RepositoryListener listener )
    {
        if ( listener != null )
        {
            listeners.add( listener );
        }
    }

    
Removes the specified listener from the multicast chain. Trying to remove a non-existing listener has no effect.
Params:
listener – The listener to remove, may be null./**
     * Removes the specified listener from the multicast chain. Trying to remove a non-existing listener has no effect.
     * 
     * @param listener The listener to remove, may be {@code null}.
     */
    public void remove( RepositoryListener listener )
    {
        if ( listener != null )
        {
            listeners.remove( listener );
        }
    }

    @SuppressWarnings( "EmptyMethod" )
    protected void handleError( RepositoryEvent event, RepositoryListener listener, RuntimeException error )
    {
        // default just swallows errors
    }

    @Override
    public void artifactDeployed( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDeployed( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactDeploying( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDeploying( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactDescriptorInvalid( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDescriptorInvalid( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactDescriptorMissing( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDescriptorMissing( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactDownloaded( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDownloaded( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactDownloading( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactDownloading( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactInstalled( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactInstalled( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactInstalling( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactInstalling( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactResolved( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactResolved( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void artifactResolving( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.artifactResolving( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataDeployed( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataDeployed( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataDeploying( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataDeploying( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataDownloaded( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataDownloaded( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataDownloading( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataDownloading( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataInstalled( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataInstalled( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataInstalling( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataInstalling( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataInvalid( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataInvalid( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataResolved( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataResolved( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

    @Override
    public void metadataResolving( RepositoryEvent event )
    {
        for ( RepositoryListener listener : listeners )
        {
            try
            {
                listener.metadataResolving( event );
            }
            catch ( RuntimeException e )
            {
                handleError( event, listener, e );
            }
        }
    }

}