Xor. Not strictly necessary, but the logical equivalent is a dog to type.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@277431 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/CoreTasks/conditions.html

@@ -49,6 +49,15 @@ <h4>or</h4> <p>
 shortcut semantics as the Java || operator, as soon as one of the
 nested conditions is true, no other condition will be evaluated.</p>
 
+<h4>xor</h4>
+<p>The <code>&lt;xor&gt;</code> element performs an exclusive
+or on all nested elements, similar to the <code>^</code> operator
+in Java. It only evaluates to true if an odd number of nested conditions
+are true. There is no shortcutting of evaluation, unlike the <code>&lt;and&gt;</code>
+and <code>&lt;or&gt;</code> tests.
+It doesn't have any attributes and accepts all nested
+elements of the condition task as nested elements as well.</p>
+
 <h4>available</h4>
 <p>This condition is identical to the <a
 href="available.html">Available</a> task, all attributes and nested

src/etc/testcases/taskdefs/conditions/xor.xml

@@ -0,0 +1,95 @@
+<project default="all">
+
+<!-- 
+  Xor semantics
+  
+  in  out
+  ==  ===
+  00   0
+  01   1
+  10   1
+  00   0
+
+-->
+
+  <target name="testEmpty" >
+    <fail message="empty test">
+      <condition>
+          <xor/>
+      </condition>
+    </fail>
+  </target>
+
+  <target name="test1" >
+    <fail message="testTrue">
+      <condition>
+        <not>
+          <xor>
+            <istrue value="true" />
+          </xor>
+        </not>
+      </condition>
+    </fail>
+  </target>
+  
+  <target name="test0" >
+    <fail message="testFalse">
+      <condition>
+          <xor>
+            <istrue value="" />
+          </xor>
+      </condition>
+    </fail>
+  </target>
+
+  
+  <target name="test10" >
+    <fail message="test10">
+      <condition>
+        <not>
+          <xor>
+            <istrue value="true" />
+            <istrue value="" />
+          </xor>
+        </not>
+      </condition>
+    </fail>
+  </target>
+
+  <target name="test01" >
+    <fail message="test01">
+      <condition>
+        <not>
+          <xor>
+            <istrue value="" />
+            <istrue value="true" />
+          </xor>
+        </not>
+      </condition>
+    </fail>
+  </target>
+  
+  <target name="test00" >
+    <fail message="test10">
+      <condition>
+        <xor>
+            <istrue value="" />
+            <istrue value="" />
+        </xor>
+      </condition>
+    </fail>
+  </target>
+  
+  <target name="test11" >
+    <fail message="test11">
+      <condition>
+          <xor>
+            <istrue value="" />
+            <istrue value="" />
+          </xor>
+      </condition>
+    </fail>
+  </target>
+
+  
+</project>

src/main/org/apache/tools/ant/taskdefs/condition/Xor.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright  2005 The Apache Software Foundation
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildException;
+
+import java.util.Enumeration;
+
+/**
+ * <tt>Xor</tt> task to exclusive or operations.
+ * This does not shortcut stuff
+ */
+public class Xor extends ConditionBase implements Condition {
+
+    /**
+     * @return true if all the contained conditions evaluates to true
+     * @throws org.apache.tools.ant.BuildException
+     *          if an error occurs
+     */
+    public boolean eval() throws BuildException {
+        Enumeration e = getConditions();
+        //initial state is false.
+        boolean state=false;
+        while (e.hasMoreElements()) {
+            Condition c = (Condition) e.nextElement();
+            //every condition is xored against the previous one
+            state ^= c.eval();
+        }
+        return state;
+    }
+
+}

src/main/org/apache/tools/ant/types/defaults.properties

@@ -41,4 +41,4 @@ ispingable=org.apache.tools.ant.taskdefs.optional.condition.IsPingable
 mavenrepository=org.apache.tools.ant.taskdefs.repository.MavenRepository
 scriptselector=org.apache.tools.ant.types.optional.ScriptSelector
 scriptcondition=org.apache.tools.ant.types.optional.ScriptCondition
-
+xor=org.apache.tools.ant.taskdefs.condition.Xor

src/testcases/org/apache/tools/ant/taskdefs/condition/XorTest.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright  2005 The Apache Software Foundation
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildFileTest;
+
+/**
+ * Test that Xor follows the conventional boolean logic semantics
+ * (a ^ b) === (a||b)&!(a&&b)
+ */
+public class XorTest extends BuildFileTest {
+
+    public XorTest(String name) {
+        super(name);
+    }
+
+
+    /**
+     * The JUnit setup method
+     */
+    public void setUp() {
+        configureProject("src/etc/testcases/taskdefs/conditions/xor.xml");
+    }
+
+    public void testEmpty() {
+        executeTarget("testEmpty");
+    }
+
+    public void test0() {
+        executeTarget("test0");
+    }
+
+    public void test1() {
+        executeTarget("test1");
+    }
+
+    public void test00() {
+        executeTarget("test00");
+    }
+
+    public void test10() {
+        executeTarget("test10");
+    }
+
+    public void test01() {
+        executeTarget("test01");
+    }
+
+    public void test11() {
+        executeTarget("test11");
+    }
+
+}