Handle incremental upload/download

src/main/java/org/codehaus/mojo/wagon/CopyMojo.java

@@ -19,13 +19,15 @@
  * under the License.
  */
 
+import java.io.File;
 import java.io.IOException;
 
 import org.apache.maven.plugins.annotations.Component;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.wagon.Wagon;
 import org.apache.maven.wagon.WagonException;
+import org.codehaus.mojo.wagon.shared.ContinuationType;
 import org.codehaus.mojo.wagon.shared.WagonCopy;
 import org.codehaus.mojo.wagon.shared.WagonFileSet;
 
@@ -60,10 +62,26 @@ public class CopyMojo
     @Parameter( property = "wagon.caseSensitive")
     private boolean caseSensitive = true;
 
+    /**
+     * Local directory to store downloaded artifacts. This directory is needed in order to use continuation type ONLY_MISSING during the download from source Wagon.
+     * If not provided, the artifacts are downloaded to a temporary directory and the continuation type ONLY_MISSING will only work during the upload to target Wagon
+     */
+    @Parameter( property = "wagon.downloadDirectory" )
+    private File downloadDirectory;
+
+    /**
+     * Configure the continuation type.
+     * When continuation type is ONLY_MISSING, download file from source Wagon that do not exist in
+     * downloadDirectory and copy files that do not exist in target Wagon
+     * When continuation type is NONE, copy all files
+     */
+    @Parameter( property = "wagon.continuationType" )
+    private ContinuationType continuationType = ContinuationType.NONE;
+
     /**
      * Remote path relative to target's url to copy files to.
      */
-    @Parameter( property = "wagon.toDir")
+    @Parameter( property = "wagon.toDir" )
     private String toDir = "";
 
     @Component
@@ -74,8 +92,11 @@ protected void copy( Wagon srcWagon, Wagon targetWagon )
         throws IOException, WagonException
     {
         WagonFileSet fileSet = this.getWagonFileSet( fromDir, includes, excludes, caseSensitive, toDir );
-
-        wagonCopy.copy( srcWagon, fileSet, targetWagon, optimize, this.getLog() );
+        if ( downloadDirectory != null )
+        {
+            fileSet.setDownloadDirectory(downloadDirectory);
+        }
+        wagonCopy.copy(srcWagon, fileSet, targetWagon, optimize, this.getLog(), continuationType);
     }
 
 }

src/main/java/org/codehaus/mojo/wagon/DownloadMojo.java

@@ -25,6 +25,7 @@
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.wagon.Wagon;
 import org.apache.maven.wagon.WagonException;
+import org.codehaus.mojo.wagon.shared.ContinuationType;
 import org.codehaus.mojo.wagon.shared.WagonFileSet;
 
 /**
@@ -41,14 +42,23 @@ public class DownloadMojo
     @Parameter( property = "wagon.toDir", defaultValue = "${project.build.directory}/wagon-plugin")
     private File toDir;
 
+
+    /**
+     * Configure the continuation type
+     * When continuation type is ONLY_MISSING, download file from source Wagon that do not exist in toDir directory
+     * When continuation type is NONE, download all files
+     */
+    @Parameter( property = "wagon.continuationType")
+    private ContinuationType continuationType = ContinuationType.NONE;
+
     @Override
     protected void execute( Wagon wagon )
         throws WagonException
     {
         WagonFileSet fileSet = this.getWagonFileSet();
         fileSet.setDownloadDirectory( this.toDir );
 
-        this.wagonDownload.download( wagon, fileSet, this.getLog() );
+        this.wagonDownload.download( wagon, fileSet, this.getLog(), continuationType );
     }
 
 }

src/main/java/org/codehaus/mojo/wagon/UploadMojo.java

@@ -29,6 +29,7 @@
 import org.apache.maven.shared.model.fileset.FileSet;
 import org.apache.maven.wagon.Wagon;
 import org.apache.maven.wagon.WagonException;
+import org.codehaus.mojo.wagon.shared.ContinuationType;
 import org.codehaus.mojo.wagon.shared.WagonUpload;
 import org.codehaus.plexus.util.StringUtils;
 
@@ -85,6 +86,14 @@ public class UploadMojo
     @Component
     protected WagonUpload wagonUpload;
 
+    /**
+     * Configure the continuation type
+     * When continuation type is ONLY_MISSING, upload files that do not exist in target Wagon
+     * When continuation type is NONE, upload all files
+     */
+    @Parameter( property = "wagon.continuationType" )
+    private ContinuationType continuationType = ContinuationType.NONE;
+
     @Override
     protected void execute( Wagon wagon )
         throws WagonException, IOException
@@ -109,7 +118,7 @@ protected void execute( Wagon wagon )
 
         fileSet.setOutputDirectory( toDir );
 
-        this.wagonUpload.upload( wagon, fileSet, optimize );
+        this.wagonUpload.upload( wagon, fileSet, optimize, continuationType );
     }
 
 }

src/main/java/org/codehaus/mojo/wagon/shared/ContinuationType.java

@@ -0,0 +1,12 @@
+package org.codehaus.mojo.wagon.shared;
+
+/**
+ * Continuation type is used to configure the download/upload continuation
+ */
+public enum ContinuationType {
+  /** no continuation (old default)*/
+  NONE,
+  /** skip existing files */
+  ONLY_MISSING
+
+}

src/main/java/org/codehaus/mojo/wagon/shared/DefaultWagonCopy.java

@@ -44,7 +44,7 @@ public class DefaultWagonCopy
     private WagonUpload uploader;
 
     @Override
-    public void copy( Wagon src, WagonFileSet wagonFileSet, Wagon target, boolean optimize, Log logger )
+    public void copy(Wagon src, WagonFileSet wagonFileSet, Wagon target, boolean optimize, Log logger, ContinuationType continuationType)
         throws WagonException, IOException
     {
         if ( wagonFileSet == null )
@@ -64,13 +64,13 @@ public void copy( Wagon src, WagonFileSet wagonFileSet, Wagon target, boolean op
 
         try
         {
-            this.downloader.download( src, wagonFileSet, logger );
+            this.downloader.download( src, wagonFileSet, logger, continuationType );
 
             FileSet localFileSet = new FileSet();
             localFileSet.setDirectory( wagonFileSet.getDownloadDirectory().getAbsolutePath() );
             localFileSet.setOutputDirectory( wagonFileSet.getOutputDirectory() );
 
-            this.uploader.upload( target, localFileSet, optimize );
+            this.uploader.upload( target, localFileSet, optimize, continuationType );
         }
         finally
         {

src/main/java/org/codehaus/mojo/wagon/shared/DefaultWagonDownload.java

@@ -57,7 +57,7 @@ public List getFileList( Wagon wagon, WagonFileSet fileSet, Log logger )
     }
 
     @Override
-    public void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger )
+    public void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger, ContinuationType continuationType )
         throws WagonException
     {
         List fileList = this.getFileList( wagon, remoteFileSet, logger );
@@ -82,12 +82,25 @@ public void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger )
                 remoteFile = remoteFileSet.getDirectory() + "/" + remoteFile;
             }
 
-            logger.info( "Downloading " + url + remoteFile + " to " + destination + " ..." );
-
-            wagon.get( remoteFile, destination );
+            if( continuationType.equals(ContinuationType.ONLY_MISSING) && destination.exists())
+            {
+                logger.info( "Skipping download " + url + remoteFile + " to " + destination + " ...Destination already exist" );
+            }
+            else
+            {
+                logger.info( "Downloading " + url + remoteFile + " to " + destination + " ..." );
+                wagon.get(remoteFile, destination);
+            }
         }
     }
 
+    @Override
+    public void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger)
+        throws WagonException
+    {
+        download(wagon, remoteFileSet, logger, ContinuationType.NONE);
+    }
+
     @Override
     public boolean exists( Wagon wagon, String resource )
         throws WagonException

src/main/java/org/codehaus/mojo/wagon/shared/DefaultWagonUpload.java

@@ -48,7 +48,7 @@ public class DefaultWagonUpload
     @Requirement
     private ArchiverManager archiverManager;
 
-    public void upload( Wagon wagon, FileSet fileset )
+    public void uploadBasic(Wagon wagon, FileSet fileset, ContinuationType continuationType)
         throws WagonException
     {
 
@@ -76,9 +76,14 @@ public void upload( Wagon wagon, FileSet fileset )
 
             File source = new File( fileset.getDirectory(), file );
 
-            LOG.info( "Uploading " + source + " to " + url + relativeDestPath + " ..." );
-
-            wagon.put( source, relativeDestPath );
+            if ( continuationType.equals(ContinuationType.ONLY_MISSING) && wagon.resourceExists(relativeDestPath) )
+            {
+                LOG.info("Skipping upload " + source + " to " + url + relativeDestPath + " ... Destination already exist");
+            } else
+            {
+                LOG.info("Uploading " + source + " to " + url + relativeDestPath + " ...");
+                wagon.put(source, relativeDestPath);
+            }
         }
 
     }
@@ -87,9 +92,16 @@ public void upload( Wagon wagon, FileSet fileset )
     public void upload( Wagon wagon, FileSet fileset, boolean optimize )
         throws WagonException, IOException
     {
-        if ( !optimize )
+        upload(wagon, fileset, optimize, ContinuationType.NONE);
+    }
+
+    @Override
+    public void upload( Wagon wagon, FileSet fileset, boolean optimize, ContinuationType continuationType)
+        throws WagonException, IOException
+    {
+        if (!optimize)
         {
-            upload( wagon, fileset );
+            uploadBasic( wagon, fileset, continuationType);
             return;
         }
 

src/main/java/org/codehaus/mojo/wagon/shared/WagonCopy.java

@@ -34,16 +34,19 @@ public interface WagonCopy
     /**
      * Transfer files between 2 Wagon URLs. If download directory is not given in the fileset a temporary one will be
      * created.
-     * 
+     *
      * @param fromWagon - source Wagon
      * @param fileset - file set to copy
      * @param toWagon - target Wagon
      * @param optimize - locally compressed and remotely uncompress for scp only
      * @param logger - logger used
+     * @param continuationType - continuation type.
+     *        When continuation type is ONLY_MISSING, download file from source Wagon that do not
+     *        exist in downloadDirectory and copy files that do not exist in target Wagon
+     *        When continuation type is NONE, copy all files
      * @throws WagonException if any wagon error
      * @throws IOException if any io error
      */
-    void copy( Wagon fromWagon, WagonFileSet fileset, Wagon toWagon, boolean optimize, Log logger )
-        throws WagonException, IOException;
-
+    void copy( Wagon fromWagon, WagonFileSet fileset, Wagon toWagon, boolean optimize, Log logger, ContinuationType continuationType )
+            throws WagonException, IOException;
 }

src/main/java/org/codehaus/mojo/wagon/shared/WagonDownload.java

@@ -40,15 +40,29 @@ public interface WagonDownload
      */
     List getFileList( Wagon wagon, WagonFileSet fileSet, Log logger )
         throws WagonException;
+    /**
+     * @param wagon - a Wagon instance
+     * @param remoteFileSet - Criteria to build the list
+     * @param logger - logger used
+     * @param continuationType - continuation type.
+     *                        When ONLY_MISSING, download only files that do not already exist in destination
+     *                        When continuation type is NONE, download all files
+     * @throws WagonException if any wagon error
+     */
+    void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger, ContinuationType continuationType )
+            throws WagonException;
 
     /**
      * @param wagon - a Wagon instance
      * @param remoteFileSet - Criteria to build the list
      * @param logger - logger used
+     *
      * @throws WagonException if any wagon error
      */
     void download( Wagon wagon, WagonFileSet remoteFileSet, Log logger )
-        throws WagonException;
+            throws WagonException;
+
+
 
     /**
      * @param wagon - a Wagon instance

src/main/java/org/codehaus/mojo/wagon/shared/WagonUpload.java

@@ -33,7 +33,20 @@ public interface WagonUpload
 
     /**
      * Upload a set of files via FileSet interface to a remote repository via Wagon
-     * 
+     *
+     * @param wagon - a Wagon instance
+     * @param fileset file set to upload
+     * @param optimize locally compressed and uncompress at the remote site if scp is use
+     * @param continuationType continuation type. Incremental upload will only upload resources that doesn't exist
+     * @throws WagonException if nay wagon exception
+     * @throws IOException if any io exception
+     */
+    void upload( Wagon wagon, FileSet fileset, boolean optimize, ContinuationType continuationType )
+            throws WagonException, IOException;
+
+    /**
+     * Upload a set of files via FileSet interface to a remote repository via Wagon
+     *
      * @param wagon - a Wagon instance
      * @param fileset file set to upload
      * @param optimize locally compressed and uncompress at the remote site if scp is use