/*
 *  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.tools.ant.taskdefs; */
/* * Portion Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.*/

package com.nokia.ant.taskdefs;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.TaskContainer;
import org.apache.tools.ant.taskdefs.*;

/**
 * Retries the nested task a set number of times
 * 
 * @since Ant 1.7.1
 */
public class RetryTask extends Task implements TaskContainer
{

    /**
     * task to execute n times
     */
    private Task nestedTask;

    /**
     * set retryCount to 1 by default
     */
    private int retryCount = 1;

    /**
     * set sleepTime to 0 by default
     */
    private int sleepTime;

    /**
     * set the task
     * 
     * @param t
     *            the task to retry.
     */
    public synchronized void addTask(Task t)
    {
        if (nestedTask != null)
        {
            throw new BuildException("The retry task container accepts a single nested task"
                    + " (which may be a sequential task container)");
        }
        nestedTask = t;
    }

    /**
     * set the number of times to retry the task
     * 
     * @param n
     *            the number to use.
     */
    public void setRetryCount(int n)
    {
        retryCount = n;
    }

    /**
     * set the sleep time inbetween each retry
     * 
     * @param n
     *            the time in ms to sleep between each retry.
     */
    public void setSleepTime(int n)
    {
        sleepTime = n;
    }

    /**
     * perform the work
     * 
     * @throws BuildException
     *             if there is an error.
     */
    public void execute()
    {
        StringBuffer errorMessages = new StringBuffer();
        String br = getProject().getProperty("line.separator");
        for (int i = 0; i <= retryCount; i++)
        {
            try
            {
                nestedTask.perform();
                break;
            }
            catch (Exception e)
            {
                errorMessages.append(e.getMessage());
                if (i >= retryCount)
                {
                    StringBuffer exceptionMessage = new StringBuffer();
                    exceptionMessage.append("Task [").append(nestedTask.getTaskName());
                    exceptionMessage.append("] failed after [").append(retryCount);
                    exceptionMessage.append("] attempts; giving up.").append(br);
                    exceptionMessage.append("Error messages:").append(br);
                    exceptionMessage.append(errorMessages);
                    throw new BuildException(exceptionMessage.toString(), getLocation());
                }
                log("Attempt [" + i + "]:  error occurred; retrying...", e, Project.MSG_INFO);
                errorMessages.append(br);
                if (sleepTime > 0)
                {
                    Sleep sleepTimer = new Sleep();
                    sleepTimer.setMilliseconds(sleepTime);
                    sleepTimer.execute();
                }
            }
        }
    }
}
