Update link creation for use Java API instead of ln or mklink commands

src/main/java/ome/formats/importer/transfers/AbstractExecFileTransfer.java

@@ -34,8 +34,7 @@
 import omero.model.OriginalFile;
 
 /**
- * Local-only file transfer mechanism which makes use of soft-linking.
- * This is only useful where the command "ln -s source target" will work.
+ * Abstract base class for file transfer implementations that link or copy files.
  *
  * @since 5.0
  */
@@ -46,9 +45,7 @@ public abstract class AbstractExecFileTransfer extends AbstractFileTransfer {
     private static final String SEPARATOR = System.getProperty("line.separator");
 
     /**
-     * "Transfer" files by soft-linking them into place. This method is likely
-     * re-usable for other general "linking" strategies by overriding
-     * {@link #createProcessBuilder(File, File)} and the other protected methods here.
+     * Transfer files as specified by the {@link #exec(File, File)} implementation.
      */
     public String transfer(TransferState state) throws IOException, ServerError {
         RawFileStorePrx rawFileStore = start(state);
@@ -151,14 +148,24 @@ protected RuntimeException failLocationCheck(File location, String msg) {
     }
 
     /**
-     * Executes a local command and fails on non-0 return codes.
+     * If {@link createProcessBuilder(File, File)} returns non-null,
+     * executes a local command corresponding to the ProcessBuilder
+     * and fails on non-0 return codes.
+     *
+     * If the ProcessBuilder is null, this method does nothing by default.
+     *
+     * This method should be overridden by subclasses, see for example
+     * {@link CopyFileTransfer}.
      *
      * @param file the source file
      * @param location the target on the server
      * @throws IOException for problems with the source file
      */
     protected void exec(File file, File location) throws IOException {
         ProcessBuilder pb = createProcessBuilder(file, location);
+        if (pb == null) {
+            return;
+        }
         pb.redirectErrorStream(true);
         Process process = pb.start();
         Integer rcode = null;
@@ -240,11 +247,11 @@ protected void checkTarget(File location, TransferState state) throws ServerErro
      * @param file File to be copied.
      * @param location Location to copy to.
      * @return an instance ready for performing the transfer
+     * @deprecated override {@link #exec(File, File)} instead
      */
-    protected abstract ProcessBuilder createProcessBuilder(File file, File location);
-
-    protected void printLine() {
-        log.error("*******************************************");
+    @Deprecated
+    protected ProcessBuilder createProcessBuilder(File file, File location) {
+        return null;
     }
 
 }

src/main/java/ome/formats/importer/transfers/CopyFileTransfer.java

@@ -21,44 +21,26 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.List;
 
 /**
- * Local-only file transfer mechanism which makes use of the plaform
- * copy command.
- *
- * This is only useful where the commands "cp source target" (Unix) or
- * "copy source target" (Windows) will work.
+ * Local-only file transfer mechanism.
  *
  * @since 5.0.7
  */
 public class CopyFileTransfer extends AbstractExecFileTransfer {
 
     /**
-     * Executes "cp file location" (Unix) or "cp file location" (Windows)
-     * and fails on non-0 return codes.
+     * Copies a file from one location to another.
      *
      * @param file File to be copied
      * @param location Location to copy to.
      * @throws IOException
      */
-    protected ProcessBuilder createProcessBuilder(File file, File location) {
-        ProcessBuilder pb = new ProcessBuilder();
-        List<String> args = new ArrayList<String>();
-        if (isWindows()) {
-            args.add("cmd");
-            args.add("/c");
-            args.add("cp");
-            args.add(file.getAbsolutePath());
-            args.add(location.getAbsolutePath());
-        } else {
-            args.add("cp");
-            args.add(file.getAbsolutePath());
-            args.add(location.getAbsolutePath());
-        }
-        pb.command(args);
-        return pb;
+    protected void exec(File file, File location) throws IOException {
+        Files.copy(Paths.get(file.getAbsolutePath()), Paths.get(location.getAbsolutePath()));
     }
 
     /**

src/main/java/ome/formats/importer/transfers/HardlinkFileTransfer.java

@@ -21,46 +21,26 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.List;
 
 /**
  * Local-only file transfer mechanism which makes use of hard-linking.
  *
- * This is only useful where the commands "ln source target" (Unix) or
- * "mklink /H target source" (Windows) will work.
- *
  * @since 5.0
  */
 public class HardlinkFileTransfer extends AbstractExecFileTransfer {
 
     /**
-     * Executes "ln file location" (Unix) or "mklink /H location file" (Windows)
-     * and fails on non-0 return codes.
+     * Creates a hard link.
      *
      * @param file File to be copied.
      * @param location Location to copy to.
      * @throws IOException
-     *
      */
-    // TODO Java7: replace ln once Java6 is dropped
-    protected ProcessBuilder createProcessBuilder(File file, File location) {
-        ProcessBuilder pb = new ProcessBuilder();
-        List<String> args = new ArrayList<String>();
-        if (isWindows()) {
-            args.add("cmd");
-            args.add("/c");
-            args.add("mklink");
-            args.add("/H");
-            args.add(location.getAbsolutePath());
-            args.add(file.getAbsolutePath());
-        } else {
-            args.add("ln");
-            args.add(file.getAbsolutePath());
-            args.add(location.getAbsolutePath());
-        }
-        pb.command(args);
-        return pb;
+    protected void exec(File file, File location) throws IOException {
+        Files.createLink(Paths.get(location.getAbsolutePath()), Paths.get(file.getAbsolutePath()));
     }
 
     /**

src/main/java/ome/formats/importer/transfers/SymlinkFileTransfer.java

@@ -21,45 +21,26 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.List;
 
 /**
  * Local-only file transfer mechanism which makes use of soft-linking.
  *
- *  This is only useful where the commands "ln -s source target" (Unix) or
- * "mklink target source" (Windows) will work.
- *
  * @since 5.0
  */
 public class SymlinkFileTransfer extends AbstractExecFileTransfer {
 
     /**
-     * Executes "ln -s file location" (Unix) or "mklink location file" (Windows)
-     * and fails on non-0 return codes.
+     * Creates a symlink.
      *
      * @param file File to be copied.
      * @param location Location to copy to.
      * @throws IOException
      */
-    // TODO Java7: replace ln once Java6 is dropped
-    protected ProcessBuilder createProcessBuilder(File file, File location) {
-        ProcessBuilder pb = new ProcessBuilder();
-        List<String> args = new ArrayList<String>();
-        if (isWindows()) {
-            args.add("cmd");
-            args.add("/c");
-            args.add("mklink");
-            args.add(location.getAbsolutePath());
-            args.add(file.getAbsolutePath());
-        } else {
-            args.add("ln");
-            args.add("-s");
-            args.add(file.getAbsolutePath());
-            args.add(location.getAbsolutePath());
-        }
-        pb.command(args);
-        return pb;
+    protected void exec(File file, File location) throws IOException {
+        Files.createSymbolicLink(Paths.get(location.getAbsolutePath()), Paths.get(file.getAbsolutePath()));
     }
 
     /**