Mongodb support

src/main/java/picoded/dstack/FileWorkspace.java

@@ -4,11 +4,16 @@
 import picoded.core.conv.StringConv;
 
 import java.io.File;
+import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.util.List;
 import java.util.Set;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * Represent a file storage backend for a workspace
  * 
@@ -133,16 +138,46 @@ default void writeString(final String filepath, String content, String encoding)
 	//--------------------------------------------------------------------------
 
 	/**
-	 * Get the input stream representation of a given filepath
+	 * Get the input stream representation of a given filepath.
+	 * 
+	 * You are expected to close, the stream on your own, to avoid memory leaks
 	 * 
 	 * @param filePath in the workspace to extract
-	 * @return the file contents, null if file does not exists
+	 * @return the file contents as an input stream, null if file does not exists
 	 */
 	default InputStream readInputStream(final String filePath) {
 		byte[] byteArr = readByteArray(filePath);
 		return new ByteArrayInputStream(byteArr);
 	}
 
+	/**
+	 * Reads an input stream, and writes it to a fil, creating the file if it does not exist.
+	 * the parent directories of the file will be created if they do not exist.
+	 *
+	 * Note that depending on the implementaiton, this may not be optimized,
+	 * and may only return after the OutputStream is fully processedd.
+	 * 
+	 * @param filepath in the workspace to extract
+	 * @param data the content to write to the file
+	 **/
+	default void writeInputStream(final String filepath, final InputStream data) {
+		// Converts it to bytearray respectively
+		byte[] rawBytes = null;
+		try {
+			rawBytes = IOUtils.toByteArray(data);
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		} finally {
+			try {
+				data.close();
+			} catch (IOException e) {
+				throw new RuntimeException(e);
+			}
+		}
+		// Does the bytearray writes
+		writeByteArray(filepath, rawBytes);
+	}
+
 	//
 	// Folder Pathing support
 	//--------------------------------------------------------------------------

src/main/java/picoded/dstack/KeyLongMap.java

@@ -180,39 +180,10 @@ default Long removeValue(Object key) {
 	 **/
 	default Long addAndGet(Object key, Object delta) {
 		//
-		// NOTE : The default implmentation of addAndGet,
-		//        or getAndAdd relies on repetaed tries using
-		//        weakCompareAndSet, while functional.
-		//        Is highly inefficent in most cases
+		// We simply use get and add, with the delta,
+		// this reduce the amount of permutation needed to support
 		//
-
-		// Validate and convert the key to String
-		if (key == null) {
-			throw new IllegalArgumentException("key cannot be null in addAndGet");
-		}
-		String keyAsString = key.toString();
-
-		// Attempt to update the key for 5 times before throwing exception
-		for (int tries = 0; tries < 5; tries++) {
-			// Retrieve value from key
-			Long value = getValue(keyAsString);
-
-			// Assume value as 0 if not exist
-			if (value == null) {
-				value = new Long(0);
-			}
-
-			// Calculate the updated value
-			Long updatedValue = GenericConvert.toLong(delta) + value;
-
-			// Update the value with weakCompareAndSet and return 
-			if (weakCompareAndSet(keyAsString, value, updatedValue)) {
-				return updatedValue;
-			}
-		}
-
-		// Throw exception due to number of retries exceeded the limit
-		throw new RuntimeException("Number of retries exceeded limit for addAndGet");
+		return getAndAdd(key, delta)+GenericConvert.toLong(delta);
 	}
 
 	/**
@@ -233,7 +204,7 @@ default Long getAndAdd(Object key, Object delta) {
 
 		// Validate and convert the key to String
 		if (key == null) {
-			throw new IllegalArgumentException("key cannot be null in addAndGet");
+			throw new IllegalArgumentException("key cannot be null in");
 		}
 		String keyAsString = key.toString();
 
@@ -257,7 +228,7 @@ default Long getAndAdd(Object key, Object delta) {
 		}
 
 		// Throw exception due to number of retries exceeded the limit
-		throw new RuntimeException("Number of retries exceeded limit for addAndGet");
+		throw new RuntimeException("Number of retries exceeded limit");
 	}
 
 	/**