PluginDependencyResolutionListener.java

package org.apache.maven.plugin.internal;

/*
 * 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.Collection;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.resolver.ResolutionListener;
import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import org.apache.maven.artifact.versioning.VersionRange;

/**
 * Assists in detecting wagon providers brought into the plugin class path via legacy Maven core artifacts (e.g.
 * maven-core:2.0.6) and excluding them. A plugin should be able to explicitly declare dependencies on specific wagons
 * for its use. However, the (old) wagons pulled in transitively via legacy Maven core artifacts are usually not
 * intended as dependencies and more importantly screw up artifact resolution because they would get preferred over the
 * core wagon versions. This is a hack to provide backward-compat with Maven 2 (MNG-4528, MNG-4561).
 * 
 * @since 3.0
 * @author Benjamin Bentmann
 */
class PluginDependencyResolutionListener
    implements ResolutionListener
{

    private ArtifactFilter coreFilter;

    private LinkedList<Artifact> coreArtifacts = new LinkedList<Artifact>();

    private Artifact wagonProvider;

    private Map<Artifact, Object> bannedArtifacts = new IdentityHashMap<Artifact, Object>();

    public PluginDependencyResolutionListener( ArtifactFilter coreFilter )
    {
        this.coreFilter = coreFilter;
    }

    public void removeBannedDependencies( Collection<Artifact> artifacts )
    {
        if ( !bannedArtifacts.isEmpty() && artifacts != null )
        {
            for ( Iterator<Artifact> it = artifacts.iterator(); it.hasNext(); )
            {
                Artifact artifact = it.next();
                if ( bannedArtifacts.containsKey( artifact ) )
                {
                    it.remove();
                }
            }
        }
    }

    public void startProcessChildren( Artifact artifact )
    {
        if ( wagonProvider == null )
        {
            if ( isLegacyCoreArtifact( artifact ) )
            {
                coreArtifacts.addFirst( artifact );
            }
            else if ( !coreArtifacts.isEmpty() && isWagonProvider( artifact ) )
            {
                wagonProvider = artifact;
                bannedArtifacts.put( artifact, null );
            }
        }
    }

    private boolean isLegacyCoreArtifact( Artifact artifact )
    {
        String version = artifact.getVersion();
        return version != null && version.startsWith( "2." ) && !coreFilter.include( artifact );
    }

    public void endProcessChildren( Artifact artifact )
    {
        if ( wagonProvider == artifact )
        {
            wagonProvider = null;
        }
        else if ( coreArtifacts.peek() == artifact )
        {
            coreArtifacts.removeFirst();
        }
    }

    public void includeArtifact( Artifact artifact )
    {
        if ( wagonProvider != null )
        {
            bannedArtifacts.put( artifact, null );
        }
    }

    private boolean isWagonProvider( Artifact artifact )
    {
        if ( "org.apache.maven.wagon".equals( artifact.getGroupId() ) )
        {
            return artifact.getArtifactId().startsWith( "wagon-" );
        }
        return false;
    }

    public void manageArtifact( Artifact artifact, Artifact replacement )
    {
    }

    public void omitForCycle( Artifact artifact )
    {
    }

    public void omitForNearer( Artifact omitted, Artifact kept )
    {
    }

    public void restrictRange( Artifact artifact, Artifact replacement, VersionRange newRange )
    {
    }

    public void selectVersionFromRange( Artifact artifact )
    {
    }

    public void testArtifact( Artifact node )
    {
    }

    public void updateScope( Artifact artifact, String scope )
    {
    }

    public void updateScopeCurrentPom( Artifact artifact, String ignoredScope )
    {
    }

}