From 473e2f367f1e4640655d03ba6694c594e2e542f7 Mon Sep 17 00:00:00 2001
From: Jesus Castagnetto <jesus@castagnetto.com>
Date: Fri, 1 Feb 2013 17:59:16 -0800
Subject: [PATCH] Implementing Xor operation

---
 .../refine/expr/functions/booleans/Xor.java   | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 main/src/com/google/refine/expr/functions/booleans/Xor.java

diff --git a/main/src/com/google/refine/expr/functions/booleans/Xor.java b/main/src/com/google/refine/expr/functions/booleans/Xor.java
new file mode 100644
index 000000000..7ce081861
--- /dev/null
+++ b/main/src/com/google/refine/expr/functions/booleans/Xor.java
@@ -0,0 +1,42 @@
+/*
+  Implementing a naive XOR operation
+  Copyright 2013, Jesus M. Castagnetto
+  License: BSD 2-Clause License (http://opensource.org/licenses/BSD-2-Clause)
+*/
+
+package com.google.refine.expr.functions.booleans;
+
+import java.util.Properties;
+
+import org.json.JSONException;
+import org.json.JSONWriter;
+
+import com.google.refine.expr.EvalError;
+import com.google.refine.grel.ControlFunctionRegistry;
+import com.google.refine.grel.Function;
+
+public class Xor implements Function {
+
+    @Override
+    public Object call(Properties bindings, Object[] args) {
+        if (args.length == 2 &&
+            args[0] != null && args[0] instanceof Boolean &&
+            args[1] != null && args[0] instanceof Boolean) {
+            boolean o1 = ((Boolean) args[0]).booleanValue();
+            boolean o2 = ((Boolean) args[1]).booleanValue();
+            return o1 != o2;
+        }
+        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects 2 booleans");
+    }
+    
+    @Override
+    public void write(JSONWriter writer, Properties options)
+            throws JSONException {
+        
+        writer.object();
+        writer.key("description"); writer.value("XORs two boolean values");
+        writer.key("params"); writer.value("boolean a, boolean b");
+        writer.key("returns"); writer.value("boolean");
+        writer.endObject();
+    }
+}