Index: trunk/java-utils/src/main/java/de/ugoe/cs/util/console/GlobalDataContainer.java
===================================================================
--- trunk/java-utils/src/main/java/de/ugoe/cs/util/console/GlobalDataContainer.java	(revision 667)
+++ trunk/java-utils/src/main/java/de/ugoe/cs/util/console/GlobalDataContainer.java	(revision 667)
@@ -0,0 +1,186 @@
+package de.ugoe.cs.util.console;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * <p>
+ * This data structure can be used by the commands to store any {@link Object}.
+ * The data is stored in a key-value map, with strings as keys.
+ * </p>
+ * <p>
+ * This class is implemented as a singleton, as more than one data container
+ * does not serves no purpose.
+ * </p>
+ * 
+ * @author Steffen Herbold
+ * @version 1.0
+ */
+public class GlobalDataContainer implements Serializable {
+
+	/**
+	 * <p>
+	 * Id for object serialization.
+	 * </p>
+	 */
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * <p>
+	 * Instance of the {@link GlobalDataContainer} (implemented as singleton).
+	 * </p>
+	 */
+	transient private static GlobalDataContainer theInstance = null;
+
+	/**
+	 * <p>
+	 * Internal storage of the data.
+	 * </p>
+	 */
+	private Map<String, Object> dataObjects;
+
+	/**
+	 * <p>
+	 * Returns the instance of the container. If it does not yet exist, the data
+	 * container is created.
+	 * </p>
+	 * 
+	 * @return instance of the container
+	 */
+	public static GlobalDataContainer getInstance() {
+		if (theInstance == null) {
+			theInstance = new GlobalDataContainer();
+		}
+		return theInstance;
+	}
+
+	/**
+	 * <p>
+	 * Manual serialization of the object. Necessary to guarantee the singleton
+	 * property.
+	 * </p>
+	 * 
+	 * @param s
+	 *            output stream for the serialization
+	 * @throws IOException
+	 *             thrown if there is problem writing to the output stream
+	 */
+	private void writeObject(ObjectOutputStream s) throws IOException {
+		s.defaultWriteObject();
+		s.writeObject(dataObjects);
+	}
+
+	/**
+	 * <p>
+	 * Manual de-serialization of the object. Necessary to guarantee the
+	 * singleton property.
+	 * 
+	 * @param s
+	 *            input stream for the de-serialization
+	 * @throws IOException
+	 *             thrown if there is problem reading from the input stream
+	 * @throws ClassNotFoundException
+	 *             thrown if there is a problem reading from the input stream
+	 */
+	@SuppressWarnings("unchecked")
+	private void readObject(ObjectInputStream s) throws IOException,
+			ClassNotFoundException {
+		s.defaultReadObject();
+		if (theInstance == null) {
+			theInstance = new GlobalDataContainer();
+		}
+		theInstance.dataObjects = (Map<String, Object>) s.readObject();
+	}
+
+	/**
+	 * <p>
+	 * Manual de-serialization to guarantee the singleton property.
+	 * </p>
+	 * 
+	 * @return instance of the container
+	 */
+	private Object readResolve() {
+		return theInstance;
+	}
+
+	/**
+	 * <p>
+	 * Constructor. Creates a new GlobalDataContainer. Private to guarantee the
+	 * singleton property.
+	 * </p>
+	 */
+	private GlobalDataContainer() {
+		dataObjects = new HashMap<String, Object>();
+	}
+
+	/**
+	 * <p>
+	 * Adds data to the container.
+	 * </p>
+	 * 
+	 * @param key
+	 *            key that identifies the data
+	 * @param data
+	 *            data that is stored
+	 * @return true, if an old entry was overwritten; false otherwise
+	 */
+	public boolean addData(String key, Object data) {
+		Object previousEntry = dataObjects.put(key, data);
+		return previousEntry != null;
+	}
+
+	/**
+	 * <p>
+	 * Removes data from the container.
+	 * </p>
+	 * 
+	 * @param key
+	 *            key of the data to be removed
+	 * @return true, if the object was removed; false if it was not present
+	 */
+	public boolean removeData(String key) {
+		Object previousEntry = dataObjects.remove(key);
+		return previousEntry != null;
+	}
+
+	/**
+	 * <p>
+	 * Returns the data associated with a key or {@code null} if no data is
+	 * stored for the key.
+	 * </p>
+	 * 
+	 * @param key
+	 *            key whose data is returned
+	 * @return data associated with the key; {@code null} if no data is
+	 *         available
+	 */
+	public Object getData(String key) {
+		return dataObjects.get(key);
+	}
+
+	/**
+	 * <p>
+	 * Resets the data container, i.e., deletes all its contents.
+	 * </p>
+	 */
+	public void reset() {
+		dataObjects = new HashMap<String, Object>();
+	}
+
+	/**
+	 * <p>
+	 * Returns the keys of all objects contained in the storage.
+	 * </p>
+	 * 
+	 * @return keys of all objects in the storage
+	 */
+	public Collection<String> getAllKeys() {
+		return dataObjects.keySet();
+	}
+
+}