// SECTION-START[License Header]
// <editor-fold defaultstate="collapsed" desc=" Generated License ">
/*
 * Java Object Management and Configuration
 * Copyright (C) Christian Schulte <cs@schulte.it>, 2005-206
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   o Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   o Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $JOMC: ObjectManagerFactory.java 5061 2015-05-31 13:20:40Z schulte $
 *
 */
// </editor-fold>
// SECTION-END
package org.jomc;

// SECTION-START[Documentation]
// <editor-fold defaultstate="collapsed" desc=" Generated Documentation ">
/**
 * Factory for the {@code ObjectManager} singleton.
 *
 * <dl>
 *   <dt><b>Identifier:</b></dt><dd>org.jomc.ObjectManagerFactory</dd>
 *   <dt><b>Name:</b></dt><dd>JOMC ⁑ API</dd>
 *   <dt><b>Abstract:</b></dt><dd>Yes</dd>
 *   <dt><b>Final:</b></dt><dd>Yes</dd>
 *   <dt><b>Stateless:</b></dt><dd>No</dd>
 * </dl>
 *
 * @author <a href="mailto:cs@schulte.it">Christian Schulte</a> 1.0
 * @version 1.0
 */
// </editor-fold>
// SECTION-END
// SECTION-START[Annotations]
// <editor-fold defaultstate="collapsed" desc=" Generated Annotations ">
@javax.annotation.Generated( value = "org.jomc.tools.SourceFileProcessor 1.9", comments = "See http://www.jomc.org/jomc/1.9/jomc-tools-1.9" )
// </editor-fold>
// SECTION-END
public abstract class ObjectManagerFactory
{
    // SECTION-START[ObjectManagerFactory]

    /**
     * Constant for the name of the class providing the default {@code getObjectManager()} method.
     */
    private static final String DEFAULT_FACTORY_CLASSNAME = "org.jomc.ri.DefaultObjectManager";

    /**
     * Constant for the name of the class providing the default {@code ObjectManager} implementation.
     */
    private static final String DEFAULT_IMPLEMENTATION_CLASSNAME = "org.jomc.ri.DefaultObjectManager";

    /**
     * Constant for the name of the system property holding the {@code getObjectManager()} method's class name.
     */
    private static final String SYS_FACTORY_CLASSNAME = "org.jomc.ObjectManagerFactory";

    /**
     * Constant for the name of the system property holding the {@code ObjectManager} implementation class name.
     */
    private static final String SYS_IMPLEMENTATION_CLASSNAME = "org.jomc.ObjectManager";

    /**
     * Gets the {@code ObjectManager} singleton instance.
     * <p>
     * This method is controlled by system property {@code org.jomc.ObjectManagerFactory} providing the name of a
     * class declaring a <blockquote>{@code public static ObjectManager getObjectManager( ClassLoader )}</blockquote>
     * method called by this method to get the instance to return.
     * </p>
     * <p>
     * <b>Note:</b><br/>
     * The {@code newObjectManager} method should be used by {@code getObjectManager} implementors to retrieve a new
     * {@code ObjectManager} implementation.
     * </p>
     *
     * @param classLoader The class loader to use for getting the singleton instance; {@code null} to use the platform's
     * bootstrap class loader.
     *
     * @return The {@code ObjectManager} singleton instance.
     *
     * @see #newObjectManager(java.lang.ClassLoader)
     *
     * @throws ObjectManagementException if getting the singleton instance fails.
     */
    public static ObjectManager getObjectManager( final ClassLoader classLoader )
    {
        try
        {
            return (ObjectManager) Class.forName( System.getProperty(
                SYS_FACTORY_CLASSNAME, DEFAULT_FACTORY_CLASSNAME ), false, classLoader ).
                getMethod( "getObjectManager", ClassLoader.class ).invoke( null, classLoader );

        }
        catch ( final Exception e )
        {
            throw new ObjectManagementException( getMessage( e ), e );
        }
    }

    /**
     * Creates a new {@code ObjectManager} instance.
     * <p>
     * The object manager implementation returned by this method is controlled by system property
     * {@code org.jomc.ObjectManager} providing the name of the {@code ObjectManager} implementation class to return
     * a new instance of.
     * </p>
     *
     * @param classLoader The class loader to use for creating the instance; {@code null} to use the platform's
     * bootstrap class loader.
     *
     * @return A new {@code ObjectManager} instance.
     *
     * @throws ObjectManagementException if creating a new {@code ObjectManager} instance fails.
     */
    public static ObjectManager newObjectManager( final ClassLoader classLoader )
    {
        try
        {
            return Class.forName( System.getProperty(
                SYS_IMPLEMENTATION_CLASSNAME, DEFAULT_IMPLEMENTATION_CLASSNAME ), false, classLoader ).
                asSubclass( ObjectManager.class ).newInstance();

        }
        catch ( final Exception e )
        {
            throw new ObjectManagementException( getMessage( e ), e );
        }
    }

    private static String getMessage( final Throwable t )
    {
        return t != null
                   ? t.getMessage() != null && t.getMessage().trim().length() > 0
                         ? t.getMessage()
                         : getMessage( t.getCause() )
                   : null;

    }

    // SECTION-END
    // SECTION-START[Constructors]
    // <editor-fold defaultstate="collapsed" desc=" Generated Constructors ">
    /** Creates a new {@code ObjectManagerFactory} instance. */
    @javax.annotation.Generated( value = "org.jomc.tools.SourceFileProcessor 1.9", comments = "See http://www.jomc.org/jomc/1.9/jomc-tools-1.9" )
    public ObjectManagerFactory()
    {
        // SECTION-START[Default Constructor]
        super();
        // SECTION-END
    }
    // </editor-fold>
    // SECTION-END
    // SECTION-START[Dependencies]
    // SECTION-END
    // SECTION-START[Properties]
    // SECTION-END
    // SECTION-START[Messages]
    // SECTION-END

}