Issue #522 - If MemoryPersistence has not been opened, do not throw an exception when closing.

Signed-off-by: James Sutton <james.sutton@uk.ibm.com>

Author: jpwsutton

org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/persist/MemoryPersistence.java

@@ -26,68 +26,86 @@
  * Persistence that uses memory
  * 
  * In cases where reliability is not required across client or device 
- * restarts memory this memory peristence can be used. In cases where
+ * restarts memory this memory persistence can be used. In cases where
  * reliability is required like when clean session is set to false
  * then a non-volatile form of persistence should be used. 
  * 
  */
 public class MemoryPersistence implements MqttClientPersistence {
 
-	private Hashtable data;
+	private Hashtable<String, MqttPersistable> data;
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#close()
 	 */
 	public void close() throws MqttPersistenceException {
-		data.clear();
+		if (data != null) {
+			data.clear();
+		}	
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#keys()
 	 */
-	public Enumeration keys() throws MqttPersistenceException {
+	public Enumeration<String> keys() throws MqttPersistenceException {
+		checkIsOpen();
 		return data.keys();
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#get(java.lang.String)
 	 */
 	public MqttPersistable get(String key) throws MqttPersistenceException {
+		checkIsOpen();
 		return (MqttPersistable)data.get(key);
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#open(java.lang.String, java.lang.String)
 	 */
 	public void open(String clientId, String serverURI) throws MqttPersistenceException {
-		this.data = new Hashtable();
+		this.data = new Hashtable<String, MqttPersistable>();
 	}
 
 	/* (non-Javadoc)
-	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#put(java.lang.String, org.eclipse.paho.client.mqttv3.MqttPersistable)
+	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#put(java.lang.String, org.eclipse.paho.mqttv5.client.MqttPersistable)
 	 */
 	public void put(String key, MqttPersistable persistable) throws MqttPersistenceException {
+		checkIsOpen();
 		data.put(key, persistable);
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#remove(java.lang.String)
 	 */
 	public void remove(String key) throws MqttPersistenceException {
+		checkIsOpen();
 		data.remove(key);
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#clear()
 	 */
 	public void clear() throws MqttPersistenceException {
+		checkIsOpen();
 		data.clear();
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.paho.client.mqttv3.MqttClientPersistence#containsKey(java.lang.String)
 	 */
 	public boolean containsKey(String key) throws MqttPersistenceException {
+		checkIsOpen();
 		return data.containsKey(key);
 	}
+	
+	/**
+	 * Checks whether the persistence has been opened.
+	 * @throws MqttPersistenceException if the persistence has not been opened.
+	 */
+	private void checkIsOpen() throws MqttPersistenceException {
+		if (data == null) {
+			throw new MqttPersistenceException();
+		}
+	}
 }

org.eclipse.paho.mqttv5.client/src/main/java/org/eclipse/paho/mqttv5/client/persist/MemoryPersistence.java

@@ -26,7 +26,7 @@
  * Persistence that uses memory
  * 
  * In cases where reliability is not required across client or device 
- * restarts memory this memory peristence can be used. In cases where
+ * restarts memory this memory persistence can be used. In cases where
  * reliability is required like when clean session is set to false
  * then a non-volatile form of persistence should be used. 
  * 
@@ -39,8 +39,9 @@ public class MemoryPersistence implements MqttClientPersistence {
 	 * @see org.eclipse.paho.mqttv5.client.MqttClientPersistence#close()
 	 */
 	public void close() throws MqttPersistenceException {
-		checkIsOpen();
-		data.clear();
+		if (data != null) {
+			data.clear();
+		}	
 	}
 
 	/* (non-Javadoc)