Add a simple if task that will eventually help with ant1.x compat

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271185 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/antlib/core/IfTask.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.antlib.core;
+
+import java.util.ArrayList;
+import org.apache.avalon.excalibur.i18n.ResourceManager;
+import org.apache.avalon.excalibur.i18n.Resources;
+import org.apache.avalon.framework.configuration.Configuration;
+import org.apache.myrmidon.api.TaskException;
+import org.apache.myrmidon.framework.AbstractContainerTask;
+import org.apache.myrmidon.framework.Condition;
+import org.apache.myrmidon.interfaces.executor.ExecutionFrame;
+import org.apache.myrmidon.interfaces.executor.Executor;
+
+/**
+ * A simple task to test a supplied condition. If the condition is true
+ * then it will execute the inner tasks, else it won't.
+ *
+ * @author <a href="mailto:peter@apache.org">Peter Donald</a>
+ * @version $Revision$ $Date$
+ * @ant:task name="if"
+ */
+public class IfTask
+    extends AbstractContainerTask
+{
+    private static final Resources REZ =
+        ResourceManager.getPackageResources( IfTask.class );
+
+    private Condition m_condition;
+    private ArrayList m_tasks = new ArrayList();
+
+    /**
+     * Set if clause on pattern.
+     *
+     * @param condition the condition
+     * @exception TaskException if an error occurs
+     */
+    public void setTest( final String condition )
+        throws TaskException
+    {
+        verifyConditionNull();
+        m_condition = new Condition( true, condition );
+    }
+
+    /**
+     * Set unless clause of pattern.
+     *
+     * @param condition the unless clause
+     * @exception TaskException if an error occurs
+     */
+    public void setNotTest( final String condition )
+        throws TaskException
+    {
+        verifyConditionNull();
+        m_condition = new Condition( false, condition );
+    }
+
+    public void add( final Configuration task )
+    {
+        m_tasks.add( task );
+    }
+
+    public void execute()
+        throws TaskException
+    {
+        if( null == m_condition )
+        {
+            final String message = REZ.getString( "if.no-condition.error" );
+            throw new TaskException( message );
+        }
+
+        final Configuration[] tasks =
+            (Configuration[])m_tasks.toArray( new Configuration[ m_tasks.size() ] );
+
+        final ExecutionFrame frame = (ExecutionFrame)getService( ExecutionFrame.class );
+        final Executor executor = (Executor)getService( Executor.class );
+
+        for( int i = 0; i < tasks.length; i++ )
+        {
+            final Configuration task = tasks[ i ];
+            executor.execute( task, frame );
+        }
+    }
+
+    public String toString()
+    {
+        return "If['" + m_condition + "]";
+    }
+
+    /**
+     * Utility method to make sure condition unset.
+     * Made so that it is not possible for both if and unless to be set.
+     *
+     * @exception TaskException if an error occurs
+     */
+    private void verifyConditionNull()
+        throws TaskException
+    {
+        if( null != m_condition )
+        {
+            final String message = REZ.getString( "if.ifelse-duplicate.error" );
+            throw new TaskException( message );
+        }
+    }
+}