| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

 *

 * Copyright (C) 2007-2008 Infrastructures and Transports Department

 * of the Valencian Gobernment (CIT)

 * 

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 

 * MA  02110-1301, USA.

 * 

 */

package org.gvsig.tools.library.impl;

import java.util.Iterator;

import java.util.Set;

import org.gvsig.tools.library.LibrariesInitializer;

import org.gvsig.tools.library.Library;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 * Base implementation of an {@link LibrariesInitializer} with the

 * initialization of Libraries already implemented, delegating on child classes

 * the finding of available {@link Library} objects.

 * <p>

 * This class is NOT thread safe.

 * </p>

 * 

 * @author <a href="mailto:cordinyana@gvsig.org">C?sar Ordi?ana</a>

 */

public abstract class AbstractLibrariesInitializer implements

                LibrariesInitializer {

        private static final Logger LOG = LoggerFactory

                        .getLogger(AbstractLibrariesInitializer.class);

        private Set libs;

        private final ClassLoader classLoader;

        private boolean libsLoaded = false;

        public AbstractLibrariesInitializer() {

                classLoader = null;

        }

        public AbstractLibrariesInitializer(ClassLoader classLoader) {

                this.classLoader = classLoader;

        }

        public void initialize() {

                if (!libsLoaded) {

                        loadLibraries(classLoader);

                        libsLoaded = true;

                }

                if (libs != null && libs.size() > 0) {

                        // Call all initialize()

                        initializeLibraries(libs, false);

                }

        }

        public void postInitialize() {

                if (!libsLoaded) {

                        loadLibraries(classLoader);

                        libsLoaded = true;

                }

                if (libs != null && libs.size() > 0) {

                        // Call all postInitialize()

                        initializeLibraries(libs, true);

                }

        }

        public void fullInitialize() {

                initialize();

                postInitialize();

        }

        protected abstract Set findLibraries(Class libraryClass,

                        ClassLoader classLoader);

        private void loadLibraries(ClassLoader classLoader) {

                // Find the available Library instances

                libs = findLibraries(Library.class, classLoader);

                if (LOG.isInfoEnabled()) {

                        logLibraries(libs);

                }

        }

        private void initializeLibraries(Set libs, boolean post) {

                for (Iterator iterator = libs.iterator(); iterator.hasNext();) {

                        Library lib = (Library) iterator.next();

                        if (post) {

                                LOG.trace("Calling {}.postInitialize()", lib.getClass()

                                                .getName());

                                lib.postInitialize();

                        } else {

                                LOG.trace("Calling {}.initialize()", lib.getClass().getName());

                                lib.initialize();

                        }

                }

        }

        private void logLibraries(Set libs) {

                StringBuffer buffer = new StringBuffer();

                buffer.append("Found ").append(libs == null ? 0 : libs.size()).append(

                                " libraries:\n");

                if (libs != null) {

                        for (Iterator iterator = libs.iterator(); iterator.hasNext();) {

                                Library lib = (Library) iterator.next();

                                buffer.append("\t").append(lib.getClass().getName()).append(

                                                "\n");

                        }

                }

                LOG.info(buffer.toString());

        }

}