/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You 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.commons.launcher.types;

 import java.util.ArrayList;

 import java.util.Stack;

 import org.apache.commons.launcher.Launcher;

 import org.apache.tools.ant.BuildException;

 import org.apache.tools.ant.types.DataType;

 import org.apache.tools.ant.types.Reference;

 /**

  * A class that represents a set of nested elements of

  * {@link ConditionalVariable} objects.

  *

  * @author Patrick Luby

  */

 public class ConditionalVariableSet extends DataType {

     //------------------------------------------------------------------ Fields

     /**

      * Cached variables and nested ConditionalVariableSet objects

      */

     private ArrayList list = new ArrayList();

     //----------------------------------------------------------------- Methods

     /**

      * Add a {@link ConditionalVariable}.

      *

      * @param variable the {@link ConditionalVariable} to be

      *  added

      */

     protected void addConditionalvariable(ConditionalVariable variable) {

         if (isReference())

             throw noChildrenAllowed();

         list.add(variable);

     }

     /**

      * Add a {@link ConditionalVariableSet}.

      *

      * @param set the {@link ConditionalVariableSet} to be added

      */

     protected void addConditionalvariableset(ConditionalVariableSet set) {

         if (isReference())

             throw noChildrenAllowed();

         list.add(set);

     }

     /**

      * Get {@link ConditionalVariable} instances.

      *

      * @return the {@link ConditionalVariable} instances

      */

     public ArrayList getList() {

         // Make sure we don't have a circular reference to this instance

         if (!checked) {

             Stack stk = new Stack();

             stk.push(this);

             dieOnCircularReference(stk, project);

         }

         // Recursively work through the tree of ConditionalVariableSet objects

         // and accumulate the list of ConditionalVariable objects.

         ArrayList mergedList = new ArrayList(list.size());

         for (int i = 0; i < list.size(); i++) {

             Object o = list.get(i);

             ConditionalVariableSet nestedSet = null;

             if (o instanceof Reference) {

                 o = ((Reference)o).getReferencedObject(project);

                 // Only references to this class are allowed

                 if (!o.getClass().isInstance(this))

                     throw new BuildException(Launcher.getLocalizedString("cannot.reference", this.getClass().getName()));

                 nestedSet = (ConditionalVariableSet)o;

             } else if (o.getClass().isInstance(this)) {

                 nestedSet = (ConditionalVariableSet)o;

             } else if (o instanceof ConditionalVariable) {

                 mergedList.add(o);

             } else {

                 throw new BuildException(Launcher.getLocalizedString("cannot.nest", this.getClass().getName()));

             }

             if (nestedSet != null)

                 mergedList.addAll(nestedSet.getList());

         }

         return mergedList;

     }

     /**

      * Makes this instance a reference to another instance. You must not

      * set another attribute or nest elements inside this element if you

      * make it a reference.

      *

      * @param r the reference to another {@link ConditionalVariableSet}

      *  instance

      */

     public void setRefid(Reference r) throws BuildException {

         if (!list.isEmpty())

             throw tooManyAttributes();

         list.add(r);

         super.setRefid(r);

     }

 }