--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gwt-client/src/main/java/org/dive4elements/river/client/client/utils/DoubleValidator.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,81 @@
+package org.dive4elements.river.client.client.utils;
+
+import java.util.Map;
+
+import com.google.gwt.core.client.GWT;
+import com.google.gwt.i18n.client.NumberFormat;
+
+import com.smartgwt.client.widgets.form.fields.FormItem;
+
+import org.dive4elements.river.client.client.FLYSConstants;
+
+/**
+ * @author <a href="mailto:raimund.renkert@intevation.de">Raimund Renkert</a>
+ */
+public class DoubleValidator implements Validator {
+
+    /** The interface that provides i18n messages. */
+    protected FLYSConstants MSG = GWT.create(FLYSConstants.class);
+
+
+    /** Statically determine doubility of String value. */
+    public static boolean isDouble(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+
+        boolean valid = true;
+        String v = obj.toString();
+
+        NumberFormat f = NumberFormat.getDecimalFormat();
+
+        try {
+            if (v == null) {
+                throw new NumberFormatException("empty");
+            }
+
+            double value = f.parse(v);
+        }
+        catch (NumberFormatException nfe) {
+            valid = false;
+        }
+        return valid;
+
+    }
+
+
+    /**
+     * @return true if items value can be converted to double, if false,
+     *         expect error message in \param errors map.
+     */
+    public boolean validate(FormItem item, Map errors) {
+        boolean valid = true;
+
+        if(item.getValue() == null) {
+            return false;
+        }
+        String v = item.getValue().toString();
+
+        NumberFormat f = NumberFormat.getDecimalFormat();
+
+        try {
+            if (v == null) {
+                throw new NumberFormatException("empty");
+            }
+
+            double value = f.parse(v);
+
+            errors.remove(item.getFieldName());
+        }
+        catch (NumberFormatException nfe) {
+            errors.put(item.getFieldName(), MSG.wrongFormat());
+
+            item.focusInItem();
+
+            valid = false;
+        }
+        return valid;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
+