Added Null Pattern for DeviceStrategy and FileWrapper

src/filesystem/NullDeviceStrategy.java

@@ -0,0 +1,34 @@
+package filesystem;
+
+import java.io.IOException;
+
+import framework.DeviceStrategy;
+import framework.FileWrapper;
+
+public class NullDeviceStrategy implements DeviceStrategy {
+	private static final NullFileWrapper[] NULL_FILE_WRAPPER_ARR = {new NullFileWrapper()};
+
+	@Override
+	public boolean isADirectory() {
+		return false;
+	}
+
+	@Override
+	public FileWrapper[] listFiles() {
+		return NULL_FILE_WRAPPER_ARR;
+	}
+
+	@Override
+	public FileWrapper getFolder() {
+		return new NullFileWrapper();
+	}
+
+	@Override
+	public FileWrapper getFileInstance(String path) {
+		return new NullFileWrapper();
+	}
+
+	@Override
+	public void copyMusicToDst(FileWrapper newMusic) throws IOException { // Do nothing
+	}
+}

src/filesystem/NullFileWrapper.java

@@ -0,0 +1,37 @@
+package filesystem;
+
+import framework.FileWrapper;
+
+public class NullFileWrapper implements FileWrapper {
+	private static final NullFileWrapper[] NULL_FILE_WRAPPER_ARR = {new NullFileWrapper()};
+
+	@Override
+	public boolean isDirectory() {
+		return false;
+	}
+
+	@Override
+	public String getName() {
+		return "";
+	}
+
+	@Override
+	public String getAbsolutePath() {
+		return "";
+	}
+
+	@Override
+	public FileWrapper[] listFiles() {
+		return NULL_FILE_WRAPPER_ARR;
+	}
+
+	@Override
+	public boolean deleteFile() {
+		return false;
+	}
+
+	@Override
+	public boolean doesFileExist() {
+		return false;
+	}
+}