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 * 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,
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package org.ofbiz.base.start;

/**
 * An object that loads server startup classes.
 * <p>
 * When OFBiz starts, the main thread will create the <code>StartupLoader</code> instance and
 * then call the loader's <code>load</code> method. If the method returns without
 * throwing an exception the loader will be added to a list of initialized loaders.
 * After all instances have been created and initialized, the main thread will call the
 * <code>start</code> method of each loader in the list. When OFBiz shuts down, a
 * separate shutdown thread will call the <code>unload</code> method of each loader.
 * Implementations should anticipate asynchronous calls to the methods by different
 * threads.
 * </p>
 * 
 */
public interface StartupLoader {

    /**
     * Load a startup class.
     *
     * @param config Startup config.
     * @param args Command-line arguments.
     * @throws StartupException If an error was encountered. Throwing this exception
     * will halt loader loading, so it should be thrown only when OFBiz can't
     * operate without it.
     */
    public void load(Config config, String args[]) throws StartupException;

    /**
     * Start the startup class. This method must not block - implementations
     * that require thread blocking must create a separate thread and then return.
     * 
     * @throws StartupException If an error was encountered.
     */
    public void start() throws StartupException;

    /**
     * Stop the startup class. This method must not block.
     *
     * @throws StartupException If an error was encountered.
     */
    public void unload() throws StartupException;
}