Added ability to remove parameters by setting them to null

Author: bcsorba

nbproject/project.properties

@@ -94,7 +94,7 @@ meta.inf.dir=${src.dir}/META-INF
 mkdist.disabled=true
 platform.active=default_platform
 project.licensePath=./nbproject/licenseheader.txt
-project.version =1.0.0
+project.version =1.1.0
 run.classpath=\
     ${javac.classpath}:\
     ${build.classes.dir}

src/com/ge/corporate/piwik/tracking/PiwikJsonObject.java

@@ -37,7 +37,15 @@ public String get(String key){
     }
 
     /**
-     * Puts a custom variable at this custom key.
+     * Returns true if this object contains no custom key-value pairs.
+     * @return true if this object contains no custom key-value pairs
+     */
+    public boolean isEmpty(){
+        return size() == 0;
+    }
+    
+    /**
+     * Puts a custom value at this custom key.
      * @param key key to store value at
      * @param value value to store at specified key
      * @return previous value stored at key if present, null otherwise
@@ -55,6 +63,14 @@ public String remove(String key){
         return map.remove(key);
     }
 
+    /** 
+     * Returns the number of custom key-value pairs.
+     * @return the number of custom key-value pairs
+     */
+    public int size(){
+        return map.size();
+    }
+    
     /**
      * Produces the JSON string representing this object.<br>
      * <br>