Add if/unless attributes to <fail>.

PR: 1380

This is the first step to remove the fail functionality from input and
waitfor.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@270126 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -121,6 +121,9 @@ Other changes:
   <antcall> unless a reference of the same name already exists in the
   subbuild or inheritall has been set to false.
 
+* <fail> no supports builds to fail based on conditions via if and
+  unless attributes.
+
 Changes from Ant 1.4 to Ant 1.4.1
 ===========================================
 

docs/manual/CoreTasks/fail.html

@@ -24,6 +24,18 @@ or character data nested into the element.</p>
     <td valign="top">A message giving further information on why the build exited</td>
     <td align="center" valign="top">No</td>
   </tr>
+  <tr>
+    <td valign="top">if</td>
+    <td valign="top">Only fail if a property of the given name exists
+      in the current project</td>
+    <td align="center" valign="top">No</td>
+  </tr>
+  <tr>
+    <td valign="top">unless</td>
+    <td valign="top">Only fail if a property of the given name doesn't
+      exist in the current project</td>
+    <td align="center" valign="top">No</td>
+  </tr>
 </table>
 <h3>Examples</h3>
 <pre>  &lt;fail/&gt;</pre>

src/etc/testcases/taskdefs/fail.xml

@@ -10,4 +10,12 @@
     <fail message="test"/>
   </target>
 
+  <target name="testIf">
+    <fail if="foo" />
+  </target>
+
+  <target name="testUnless">
+    <fail unless="foo" />
+  </target>
+
 </project>

src/main/org/apache/tools/ant/Target.java

@@ -233,4 +233,5 @@ public class Target implements TaskContainer {
         String test = ProjectHelper.replaceProperties(getProject(), unlessCondition);
         return project.getProperty(test) == null;
     }
+
 }

src/main/org/apache/tools/ant/taskdefs/Exit.java

@@ -66,16 +66,27 @@ import org.apache.tools.ant.ProjectHelper;
  */
 public class Exit extends Task { 
     private String message;
+    private String ifCondition, unlessCondition;
     
     public void setMessage(String value) { 
         this.message = value;
     }
     
+    public void setIf(String c) {
+        ifCondition = c;
+    }
+
+    public void setUnless(String c) {
+        unlessCondition = c;
+    }
+
     public void execute() throws BuildException {
-        if (message != null && message.length() > 0) { 
-            throw new BuildException(message);
-        } else {
-            throw new BuildException("No message");
+        if (testIfCondition() && testUnlessCondition()) {
+            if (message != null && message.length() > 0) { 
+                throw new BuildException(message);
+            } else {
+                throw new BuildException("No message");
+            }
         }
     }
 
@@ -87,4 +98,19 @@ public class Exit extends Task {
             ProjectHelper.replaceProperties(project, msg);
     }
 
+    private boolean testIfCondition() {
+        if (ifCondition == null || "".equals(ifCondition)) {
+            return true;
+        }
+        
+        return project.getProperty(ifCondition) != null;
+    }
+
+    private boolean testUnlessCondition() {
+        if (unlessCondition == null || "".equals(unlessCondition)) {
+            return true;
+        }
+        return project.getProperty(unlessCondition) == null;
+    }
+
 }

src/testcases/org/apache/tools/ant/taskdefs/FailTest.java

@@ -54,10 +54,12 @@
 
 package org.apache.tools.ant.taskdefs;
 
+import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.BuildFileTest;
 
 /**
  * @author Nico Seessle <nico@seessle.de> 
+ * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a> 
  */
 public class FailTest extends BuildFileTest { 
     
@@ -76,4 +78,25 @@ public class FailTest extends BuildFileTest {
     public void test2() { 
         expectBuildException("test2", "it is required to fail :-)");
     }
+
+    public void testIf() {
+        try {
+            executeTarget("testIf");
+        } catch (BuildException be) {
+            fail("foo has not been defined, testIf must not fail");
+        }
+        project.setProperty("foo", "");
+        expectBuildException("testIf", "testIf must fail if foo has been set");
+    }
+
+    public void testUnless() {
+        expectBuildException("testUnless", 
+                             "testUnless must fail unless foo has been set");
+        project.setProperty("foo", "");
+        try {
+            executeTarget("testUnless");
+        } catch (BuildException be) {
+            fail("foo has been defined, testUnless must not fail");
+        }
+    }
 }