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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.ant;
     18 
     19 import org.apache.tools.ant.BuildException;
     20 import org.apache.tools.ant.Task;
     21 import org.apache.tools.ant.taskdefs.Sequential;
     22 
     23 /**
     24  * If (condition) then: {@link Sequential} else: {@link Sequential}.
     25  *
     26  * In XML:
     27  * <if condition="${some.condition}">
     28  *     <then>
     29  *     </then>
     30  *     <else>
     31  *     </else>
     32  * </if>
     33  *
     34  * both <then> and <else> behave like <sequential>.
     35  *
     36  * The presence of both <then> and <else> is not required, but one of them must be present.
     37  * <if condition="${some.condition}">
     38  *     <else>
     39  *     </else>
     40  * </if>
     41  * is perfectly valid.
     42  *
     43  */
     44 public class IfElseTask extends Task {
     45 
     46     private boolean mCondition;
     47     private boolean mConditionIsSet = false;
     48     private Sequential mThen;
     49     private Sequential mElse;
     50 
     51     /**
     52      * Sets the condition value
     53      */
     54     public void setCondition(boolean condition) {
     55         mCondition = condition;
     56         mConditionIsSet = true;
     57     }
     58 
     59     /**
     60      * Creates and returns the <then> {@link Sequential}
     61      */
     62     public Object createThen() {
     63         mThen = new Sequential();
     64         return mThen;
     65     }
     66 
     67     /**
     68      * Creates and returns the <else> {@link Sequential}
     69      */
     70     public Object createElse() {
     71         mElse = new Sequential();
     72         return mElse;
     73     }
     74 
     75     @Override
     76     public void execute() throws BuildException {
     77         if (mConditionIsSet == false) {
     78             throw new BuildException("Condition has not been set.");
     79         }
     80 
     81         // need at least one.
     82         if (mThen == null && mElse == null) {
     83             throw new BuildException("Need at least <then> or <else>");
     84         }
     85 
     86         if (mCondition) {
     87             if (mThen != null) {
     88                 mThen.execute();
     89             }
     90         } else {
     91             if (mElse != null) {
     92                 mElse.execute();
     93             }
     94         }
     95     }
     96 }
     97