Application: gvSIG desktop » Library: org.gvsig.tools

/* gvSIG. Geographic Information System of the Valencian Government

 *

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

 * of the Valencian Government (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;

import java.text.MessageFormat;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Comparator;

import java.util.HashSet;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.TreeMap;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.gvsig.tools.exception.BaseRuntimeException;

import org.gvsig.tools.library.AbstractLibrary.Required;

/**

 * 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, Library.TYPE {

    private static final Logger LOG = LoggerFactory

        .getLogger(AbstractLibrariesInitializer.class);

    private Collection libs;

    private boolean libsLoaded = false;

    private final ClassLoader[] classLoaders;

    public AbstractLibrariesInitializer() {

        classLoaders = null;

    }

    public AbstractLibrariesInitializer(ClassLoader classLoader) {

        this(new ClassLoader[] { classLoader });

    }

    public AbstractLibrariesInitializer(ClassLoader[] classLoaders) {

        this.classLoaders = classLoaders;

    }

    public void initialize() {

        this.initialize(false);

    }

    public void initialize(boolean ignoreerrors) {

        if (!libsLoaded) {

            loadLibraries(classLoaders, ignoreerrors);

            libsLoaded = true;

        }

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

            // Call all initialize()

            initializeLibraries(libs, false, ignoreerrors);

        }

    }

    public void postInitialize() {

        this.postInitialize(false);

    }

    public void postInitialize(boolean ignoreerrors) {

        if (!libsLoaded) {

            loadLibraries(classLoaders, ignoreerrors);

            libsLoaded = true;

        }

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

            // Call all postInitialize()

            initializeLibraries(libs, true, ignoreerrors);

        }

    }

    public void fullInitialize() {

        initialize();

        postInitialize();

    }

    public void fullInitialize(boolean ignoreerrors) {

        initialize(ignoreerrors);

        postInitialize(ignoreerrors);

    }

    public List getLibraries() {

        if (!libsLoaded) {

            loadLibraries(classLoaders, false);

            libsLoaded = true;

        }

        return new ArrayList(this.libs);

    }

    private void loadLibraries(ClassLoader[] classLoaders, boolean ignoreerrors) {

        // Find the available Library instances

        Set libs = new HashSet();

        LOG.info("Loading libraries of classloaders:");

        if (classLoaders == null) {

            addLibrariesOfClassLoader(libs, null, ignoreerrors);

        } else {

            for (int i = 0; i < classLoaders.length; i++) {

                addLibrariesOfClassLoader(libs, classLoaders[i], ignoreerrors);

            }

        }

        int fullSize = libs.size();

        this.libs = new OrderedLibs(libs);

        if (LOG.isInfoEnabled()) {

            logLibraries(this.libs, fullSize);

        }

    }

    private void addLibrariesOfClassLoader(Set previousFoundLibs,

        ClassLoader classLoader, boolean ignoreerrors) {

        StringBuffer logBuf = new StringBuffer();

        try {

            Set foundLibs = findLibraries(Library.class, classLoader);

            foundLibs.removeAll(previousFoundLibs);

            logBuf

                .append(new Integer(foundLibs.size()))

                .append(" new libraries found in the classloader ")

                .append(

                    classLoader == null ? "DEFAULT" : classLoader.toString())

                .append(":");

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

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

                try {

                    library.doRegistration();

                } catch (Throwable e) {

                    manageLibraryException(ignoreerrors, "doRegistration",

                        library, e);

                }

                previousFoundLibs.add(library);

                logBuf.append("\n- ").append(library);

            }

            LOG.info(logBuf.toString());

        } catch (Exception e) {

            String msg =

                MessageFormat.format(

                    "Error finding libraries of classloader {0}",

                    new String[] { classLoader.toString() });

            manageLibraryException(ignoreerrors, msg, e);

        }

    }

    protected abstract Set findLibraries(Class libraryClass,

        ClassLoader classLoader);

    private void initializeLibraries(Collection libs, boolean post,

        boolean ignoreerrors) {

        String label;

        if (post) {

            label = "postInitialize";

        } else {

            label = "initialize";

        }

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

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

            try {

                if (post) {

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

                        .getName());

                    lib.postInitialize();

                } else {

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

                        .getName());

                    lib.initialize();

                }

            } catch (Throwable e) {

                manageLibraryException(ignoreerrors, label, lib, e);

            }

        }

    }

    private void manageLibraryException(boolean ignoreerrors, String label,

        Library lib, Throwable e) {

        String msg;

        if (e instanceof BaseRuntimeException) {

            msg = ((BaseRuntimeException) e).getLocalizedMessageStack();

        } else {

            msg = e.getLocalizedMessage();

        }

        String formattedMsg =

            MessageFormat.format("Error in {0} of library {1}. {2}",

                new String[] { label, lib.getClass().getName(), msg });

        manageLibraryException(ignoreerrors, formattedMsg, e);

    }

    private void manageLibraryException(boolean ignoreerrors, String message,

        Throwable e) {

        if (ignoreerrors) {

            LOG.error(message, e);

        } else {

            if (e instanceof RuntimeException) {

                throw (RuntimeException) e;

            } else if (e instanceof Error) {

                throw (Error) e;

            }

        }

    }

    private void logLibraries(Collection libs, int fullSize) {

        StringBuffer buffer = new StringBuffer();

        buffer.append("Total libraries to initialize (")

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

            .append(fullSize).append("):");

        if (libs != null) {

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

                buffer.append("\n- ").append(iterator.next());

            }

        }

        LOG.info(buffer.toString());

    }

    private static class OrderedLibs extends ArrayList {

        private static final long serialVersionUID = -8546268624773345053L;

        // By default order alphabetically

        private Map apis;

        public OrderedLibs(Set libs) {

            apis = new TreeMap(new Comparator() {

                public int compare(Object o1, Object o2) {

                    Class class1 = (Class) o1;

                    Class class2 = (Class) o2;

                    return class1.getName().compareTo(class2.getName());

                }

            });

            orderLibs(libs);

        }

        private void orderLibs(Set libs) {

            // First create the groups of libraries, internally ordered:

            // 1: api, 2: impl, 3: serv1, 4: serv2, ...

            // (servs ordered by dependency)

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

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

                Class API = library.getLibrary();

                if (API == null) {

                    API = library.getClass();

                }

                List libraryGroup = (List) apis.get(API);

                if (libraryGroup == null) {

                    libraryGroup = new LinkedList();

                    apis.put(API, libraryGroup);

                }

                addLibraryToGroup(libraryGroup, library);

            }

            Set alreadyAddedGroups = new HashSet();

            for (Iterator iterator = apis.keySet().iterator(); iterator

                .hasNext();) {

                Class APIRequired = (Class) iterator.next();

                addFromLibraryGroup(APIRequired, alreadyAddedGroups);

            }

        }

        private void addLibraryToGroup(List libraryGroup, Library library) {

            String type = library.getType();

            // If first, don't look anything else and add it

            if (libraryGroup.size() == 0) {

                libraryGroup.add(library);

                return;

            }

            if (API.equals(type)) {

                // API library must go first

                libraryGroup.add(0, library);

            } else if (IMPL.equals(type)) {

                // Look for other implementation an replace it if priority

                // is higher, or discard

                for (int i = 0; i < libraryGroup.size(); i++) {

                    Library current = (Library) libraryGroup.get(i);

                    if (IMPL.equals(current.getType())) {

                        if (current.getPriority() < library.getPriority()) {

                            libraryGroup.set(i, library);

                            return;

                        } else {

                            return;

                        }

                    }

                }

                // If it is the first implementation, insert it after the API

                // and before the services, if any.

                Library first = (Library) libraryGroup.get(0);

                if (API.equals(first.getType())) {

                    if (libraryGroup.size() == 1) {

                        libraryGroup.add(library);

                    } else {

                        libraryGroup.add(1, library);

                    }

                    return;

                } else {

                    libraryGroup.add(0, library);

                    return;

                }

            } else { // It is a service type

                // Look for other services and insert by dependency order

                for (int i = 0; i < libraryGroup.size(); i++) {

                    Library current = (Library) libraryGroup.get(i);

                    if (SERVICE.equals(current.getType())) {

                        if (current.isRequired(library)) {

                            libraryGroup.add(i, library);

                            return;

                        }

                    }

                }

                // Otherwise add the last

                libraryGroup.add(library);

            }

        }

        private void addFromLibraryGroup(Class APIRequired,

            Set alreadyAddedGroups) {

            Collection libraryGroup = (Collection) apis.get(APIRequired);

            if (libraryGroup != null

                && !alreadyAddedGroups.contains(APIRequired)) {

                alreadyAddedGroups.add(APIRequired);

                // Add all group libraries, taking into account dependencies

                // with other library groups

                for (Iterator iterator = libraryGroup.iterator(); iterator

                    .hasNext();) {

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

                    Set requireds = library.getRequireds();

                    if (requireds != null) {

                        for (Iterator requiredsIter = requireds.iterator(); requiredsIter

                            .hasNext();) {

                            Required required = (Required) requiredsIter.next();

                            addFromLibraryGroup(required.getLibrary(),

                                alreadyAddedGroups);

                        }

                    }

                    add(library);

                }

            }

        }

    }

}