first commit

hrmsEjb/net/sf/jasperreports/engine/fill/JRDoubleStandardDeviationIncrementer.java

@@ -0,0 +1,23 @@
+package net.sf.jasperreports.engine.fill;
+
+class JRDoubleStandardDeviationIncrementer extends JRAbstractExtendedIncrementer {
+  private static JRDoubleStandardDeviationIncrementer mainInstance = new JRDoubleStandardDeviationIncrementer();
+  
+  public static JRDoubleStandardDeviationIncrementer getInstance() {
+    return mainInstance;
+  }
+  
+  public Object increment(JRCalculable variable, Object expressionValue, AbstractValueProvider valueProvider) {
+    if (expressionValue == null) {
+      if (variable.isInitialized())
+        return null; 
+      return variable.getValue();
+    } 
+    Number varianceValue = (Number)valueProvider.getValue(variable.getHelperVariable((byte)2));
+    return new Double(Math.sqrt(varianceValue.doubleValue()));
+  }
+  
+  public Object initialValue() {
+    return JRDoubleIncrementerFactory.ZERO;
+  }
+}