LinkMojo creates symbolic links to artifacts

maven-dependency-plugin/pom.xml

@@ -178,7 +178,7 @@ under the License.
     <dependency>
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-utils</artifactId>
-      <version>3.0.24</version>
+      <version>3.0.25-SNAPSHOT</version>
     </dependency>
     <dependency>
       <groupId>org.apache.maven.shared</groupId>

maven-dependency-plugin/src/main/java/org/apache/maven/plugins/dependency/AbstractDependencyMojo.java

@@ -22,6 +22,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.Field;
+import java.nio.file.Files;
 import java.util.List;
 
 import org.apache.maven.artifact.Artifact;
@@ -43,6 +44,7 @@
 import org.codehaus.plexus.archiver.zip.ZipUnArchiver;
 import org.codehaus.plexus.components.io.fileselectors.IncludeExcludeFileSelector;
 import org.codehaus.plexus.util.FileUtils;
+import org.codehaus.plexus.util.NioFiles;
 import org.codehaus.plexus.util.ReflectionUtils;
 import org.codehaus.plexus.util.StringUtils;
 
@@ -186,6 +188,39 @@ protected void copyFile( File artifact, File destFile )
         }
     }
 
+    /**
+     * Does the actual linking of the file and logging.
+     *
+     * @param artifact represents the file to link to.
+     * @param link file name of link.
+     * @throws MojoExecutionException with a message if an
+     *                                error occurs.
+     */
+    protected void linkFile( File artifact, File link )
+        throws MojoExecutionException
+    {
+        try
+        {
+            getLog().info( "Creating link " + link + " to "
+                + ( this.outputAbsoluteArtifactFilename ? artifact.getAbsolutePath() : artifact.getName() ) );
+
+            if ( artifact.isDirectory() )
+            {
+                // usual case is a future jar packaging, but there are special cases: classifier and other packaging
+                throw new MojoExecutionException( "Artifact has not been packaged yet. When used on reactor artifact, "
+                    + "copy should be executed after packaging: see MDEP-187." );
+            }
+
+            if ( link.getParentFile() != null )
+                Files.createDirectories( link.toPath().getParent() );
+            NioFiles.createSymbolicLink( link, artifact);
+        }
+        catch ( IOException e )
+        {
+            throw new MojoExecutionException( "Error creating link " + link + " to " + artifact, e );
+        }
+    }
+
     protected void unpack( Artifact artifact, File location, String encoding )
         throws MojoExecutionException
     {

maven-dependency-plugin/src/main/java/org/apache/maven/plugins/dependency/fromConfiguration/LinkMojo.java

@@ -0,0 +1,187 @@
+package org.apache.maven.plugins.dependency.fromConfiguration;
+
+/*
+ * 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 org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.dependency.utils.filters.ArtifactItemFilter;
+import org.apache.maven.plugins.dependency.utils.filters.DestFileFilter;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+
+import java.io.File;
+import java.util.List;
+
+/**
+ * Goal that creates links to a list of artifacts in the repository.
+ *
+ * @author <a href="mailto:[email protected]">Markus KARG</a>
+ * @version $Id$
+ * @since 3.0
+ */
+@Mojo( name = "link", defaultPhase = LifecyclePhase.PROCESS_SOURCES, requiresProject = false, threadSafe = true  )
+public class LinkMojo
+    extends AbstractFromConfigurationMojo
+{
+
+    /**
+     * Strip artifact version during link
+     */
+    @Parameter( property = "mdep.stripVersion", defaultValue = "false" )
+    private boolean stripVersion = false;
+
+    /**
+     * Strip artifact classifier during link
+     */
+    @Parameter( property = "mdep.stripClassifier", defaultValue = "false" )
+    private boolean stripClassifier = false;
+
+    /**
+     * Prepend artifact groupId during link
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.prependGroupId", defaultValue = "false" )
+    private boolean prependGroupId = false;
+
+    /**
+     * Use artifact baseVersion during link
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.useBaseVersion", defaultValue = "false" )
+    private boolean useBaseVersion = false;
+
+    /**
+     * The artifact to link to from commandLine.
+     * Use {@link #artifactItems} within the pom-configuration.
+     */
+    @SuppressWarnings( "unused" ) //marker-field, setArtifact(String) does the magic
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    /**
+     * <i>not used in this goal</i>
+     */
+    @Parameter
+    protected boolean useJvmChmod = true;
+
+    /**
+     * <i>not used in this goal</i>
+     */
+    @Parameter
+    protected boolean ignorePermissions;
+
+    /**
+     * Main entry into mojo. This method gets the ArtifactItems and iterates through each one passing it to
+     * linkArtifact.
+     *
+     * @throws MojoExecutionException with a message if an error occurs.
+     * @see ArtifactItem
+     * @see #getArtifactItems
+     * @see #linkArtifact(ArtifactItem)
+     */
+    @Override
+    protected void doExecute()
+        throws MojoExecutionException, MojoFailureException
+    {
+        verifyRequirements();
+
+        List<ArtifactItem> theArtifactItems =
+            getProcessedArtifactItems( new ProcessArtifactItemsRequest( stripVersion, prependGroupId,
+                                                                        useBaseVersion, stripClassifier ) );
+        for ( ArtifactItem artifactItem : theArtifactItems )
+        {
+            if ( artifactItem.isNeedsProcessing() )
+            {
+                linkArtifact( artifactItem );
+            }
+            else
+            {
+                this.getLog().info( artifactItem + " already exists in " + artifactItem.getOutputDirectory() );
+            }
+        }
+    }
+
+    /**
+     * Resolves the artifact from the repository and links to it from the specified location.
+     *
+     * @param artifactItem containing the information about the Artifact to link.
+     * @throws MojoExecutionException with a message if an error occurs.
+     * @see DependencyUtil#linkFile(File, File, Log)
+     * @see DependencyUtil#getFormattedFileName(Artifact, boolean)
+     */
+    protected void linkArtifact( ArtifactItem artifactItem )
+        throws MojoExecutionException
+    {
+        File destFile = new File( artifactItem.getOutputDirectory(), artifactItem.getDestFileName() );
+
+        linkFile( artifactItem.getArtifact().getFile(), destFile );
+    }
+
+    @Override
+    protected ArtifactItemFilter getMarkedArtifactFilter( ArtifactItem item )
+    {
+        ArtifactItemFilter destinationNameOverrideFilter =
+            new DestFileFilter( this.isOverWriteReleases(), this.isOverWriteSnapshots(), this.isOverWriteIfNewer(),
+                                false, false, false, false, this.stripVersion, prependGroupId, useBaseVersion,
+                                item.getOutputDirectory() );
+        return destinationNameOverrideFilter;
+    }
+
+    /**
+     * @return Returns the stripVersion.
+     */
+    public boolean isStripVersion()
+    {
+        return this.stripVersion;
+    }
+
+    /**
+     * @param stripVersion The stripVersion to set.
+     */
+    public void setStripVersion( boolean stripVersion )
+    {
+        this.stripVersion = stripVersion;
+    }
+
+    /**
+     * @return Returns the stripClassifier.
+     */
+    public boolean isStripClassifier()
+    {
+        return this.stripClassifier;
+    }
+
+    /**
+     * @param stripClassifier The stripClassifier to set.
+     */
+    public void setStripClassifier( boolean stripClassifier )
+    {
+        this.stripClassifier = stripClassifier;
+    }
+
+    /**
+     * @param useBaseVersion The useBaseVersion to set.
+     */
+    public void setUseBaseVersion( boolean useBaseVersion )
+    {
+        this.useBaseVersion = useBaseVersion;
+    }
+}

maven-dependency-plugin/src/site/apt/index.apt.vm

@@ -70,6 +70,8 @@ ${project.name}
   *{{{./go-offline-mojo.html}dependency:go-offline}} tells Maven to resolve everything this project is dependent on
   (dependencies, plugins, reports) in preparation for going offline.
 
+  *{{{./link-mojo.html}dependency:link}} like copy but creates symbolic links.
+
   *{{{./list-mojo.html}dependency:list}} alias for resolve that lists the dependencies for this project.
 
   *{{{./list-repositories-mojo.html}dependency:list-repositories}} displays all project dependencies and then lists the repositories used.

maven-dependency-plugin/src/site/fml/faq.fml

@@ -78,6 +78,14 @@ under the License.
         </p>
       </answer>
     </faq>
+    <faq id="link-insufficient-rights">
+      <question>Why do I get "You do not have sufficient privilege to perform this operation" when using the link goal?</question>
+      <answer><p>
+        This is a security constraint of the Windows(R) operating system. By default, it prevents anybody to create symbolic links besides administrators in elevated mode.
+        Either execute Maven as an administrator in elevated mode, or as a plain user having explicitly granted the right "Create symbolic links" by an administrator.
+      </p>
+      </answer>
+    </faq>
     <faq id="unused">
       <question>Why does my dependency analysis report <code>Unused declared dependencies</code>?</question>
       <answer><p>