Use java.nio.file consistently in FS

Since 4.0 we require Java 7 so there is no longer a need to override the
following methods in FS_POSIX, FS_Win32, FS_Win32_Cygwin
- lastModified()
- setLastModified()
- length()
- isSymlink()
- exists()
- isDirectory()
- isFile()
- isHidden()
Hence implement these methods in FS and remove overrides in subclasses.

Change-Id: I5dbde6ec806c66c86ac542978918361461021294
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties

@@ -286,7 +286,6 @@ funnyRefname=funny refname
 gcFailed=Garbage collection failed.
 gitmodulesNotFound=.gitmodules not found in tree.
 headRequiredToStash=HEAD required to stash local changes
-hiddenFilesStartWithDot=Hiding only allowed for names that start with a period
 hoursAgo={0} hours ago
 hugeIndexesAreNotSupportedByJgitYet=Huge indexes are not supported by jgit, yet
 hunkBelongsToAnotherFile=Hunk belongs to another file

org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java

@@ -345,7 +345,6 @@ public class JGitText extends TranslationBundle {
 	/***/ public String gcFailed;
 	/***/ public String gitmodulesNotFound;
 	/***/ public String headRequiredToStash;
-	/***/ public String hiddenFilesStartWithDot;
 	/***/ public String hoursAgo;
 	/***/ public String hugeIndexesAreNotSupportedByJgitYet;
 	/***/ public String hunkBelongsToAnotherFile;

org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java

@@ -247,7 +247,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public long lastModified(File f) throws IOException {
-		return f.lastModified();
+		return FileUtils.lastModified(f);
 	}
 
 	/**
@@ -260,7 +260,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public void setLastModified(File f, long time) throws IOException {
-		f.setLastModified(time);
+		FileUtils.setLastModified(f, time);
 	}
 
 	/**
@@ -273,7 +273,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public long length(File path) throws IOException {
-		return path.length();
+		return FileUtils.getLength(path);
 	}
 
 	/**
@@ -630,7 +630,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public boolean isSymLink(File path) throws IOException {
-		return false;
+		return FileUtils.isSymlink(path);
 	}
 
 	/**
@@ -642,7 +642,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public boolean exists(File path) {
-		return path.exists();
+		return FileUtils.exists(path);
 	}
 
 	/**
@@ -654,7 +654,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public boolean isDirectory(File path) {
-		return path.isDirectory();
+		return FileUtils.isDirectory(path);
 	}
 
 	/**
@@ -666,7 +666,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public boolean isFile(File path) {
-		return path.isFile();
+		return FileUtils.isFile(path);
 	}
 
 	/**
@@ -677,7 +677,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public boolean isHidden(File path) throws IOException {
-		return path.isHidden();
+		return FileUtils.isHidden(path);
 	}
 
 	/**
@@ -689,9 +689,7 @@ public abstract class FS {
 	 * @since 3.0
 	 */
 	public void setHidden(File path, boolean hidden) throws IOException {
-		if (!path.getName().startsWith(".")) //$NON-NLS-1$
-			throw new IllegalArgumentException(
-					JGitText.get().hiddenFilesStartWithDot);
+		FileUtils.setHidden(path, hidden);
 	}
 
 	/**

org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java

@@ -245,46 +245,6 @@ public class FS_POSIX extends FS {
 		return true;
 	}
 
-	@Override
-	public boolean isSymLink(File path) throws IOException {
-		return FileUtils.isSymlink(path);
-	}
-
-	@Override
-	public long lastModified(File path) throws IOException {
-		return FileUtils.lastModified(path);
-	}
-
-	@Override
-	public void setLastModified(File path, long time) throws IOException {
-		FileUtils.setLastModified(path, time);
-	}
-
-	@Override
-	public long length(File f) throws IOException {
-		return FileUtils.getLength(f);
-	}
-
-	@Override
-	public boolean exists(File path) {
-		return FileUtils.exists(path);
-	}
-
-	@Override
-	public boolean isDirectory(File path) {
-		return FileUtils.isDirectory(path);
-	}
-
-	@Override
-	public boolean isFile(File path) {
-		return FileUtils.isFile(path);
-	}
-
-	@Override
-	public boolean isHidden(File path) throws IOException {
-		return FileUtils.isHidden(path);
-	}
-
 	@Override
 	public void setHidden(File path, boolean hidden) throws IOException {
 		// no action on POSIX

org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java

@@ -183,51 +183,6 @@ public class FS_Win32 extends FS {
 		}
 	}
 
-	@Override
-	public boolean isSymLink(File path) throws IOException {
-		return FileUtils.isSymlink(path);
-	}
-
-	@Override
-	public long lastModified(File path) throws IOException {
-		return FileUtils.lastModified(path);
-	}
-
-	@Override
-	public void setLastModified(File path, long time) throws IOException {
-		FileUtils.setLastModified(path, time);
-	}
-
-	@Override
-	public long length(File f) throws IOException {
-		return FileUtils.getLength(f);
-	}
-
-	@Override
-	public boolean exists(File path) {
-		return FileUtils.exists(path);
-	}
-
-	@Override
-	public boolean isDirectory(File path) {
-		return FileUtils.isDirectory(path);
-	}
-
-	@Override
-	public boolean isFile(File path) {
-		return FileUtils.isFile(path);
-	}
-
-	@Override
-	public boolean isHidden(File path) throws IOException {
-		return FileUtils.isHidden(path);
-	}
-
-	@Override
-	public void setHidden(File path, boolean hidden) throws IOException {
-		FileUtils.setHidden(path, hidden);
-	}
-
 	/**
 	 * @since 3.3
 	 */

org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32_Cygwin.java

@@ -44,7 +44,6 @@
 package org.eclipse.jgit.util;
 
 import java.io.File;
-import java.io.IOException;
 import java.io.PrintStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -168,59 +167,6 @@ public class FS_Win32_Cygwin extends FS_Win32 {
 		return true;
 	}
 
-	@Override
-	public boolean isSymLink(File path) throws IOException {
-		return FileUtils.isSymlink(path);
-	}
-
-	@Override
-	public long lastModified(File path) throws IOException {
-		return FileUtils.lastModified(path);
-	}
-
-	@Override
-	public void setLastModified(File path, long time) throws IOException {
-		FileUtils.setLastModified(path, time);
-	}
-
-	@Override
-	public long length(File f) throws IOException {
-		return FileUtils.getLength(f);
-	}
-
-	@Override
-	public boolean exists(File path) {
-		return FileUtils.exists(path);
-	}
-
-	@Override
-	public boolean isDirectory(File path) {
-		return FileUtils.isDirectory(path);
-	}
-
-	@Override
-	public boolean isFile(File path) {
-		return FileUtils.isFile(path);
-	}
-
-	@Override
-	public boolean isHidden(File path) throws IOException {
-		return FileUtils.isHidden(path);
-	}
-
-	@Override
-	public void setHidden(File path, boolean hidden) throws IOException {
-		FileUtils.setHidden(path, hidden);
-	}
-
-	/**
-	 * @since 3.3
-	 */
-	@Override
-	public Attributes getAttributes(File path) {
-		return FileUtils.getFileAttributesBasic(this, path);
-	}
-
 	/**
 	 * @since 3.7
 	 */