fr.paris.lutece.portal.service.spring.SpringContextService.java Source code

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/*
 * Copyright (c) 2002-2014, Mairie de Paris
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  1. Redistributions of source code must retain the above copyright notice
 *     and the following disclaimer.
 *
 *  2. Redistributions in binary form must reproduce the above copyright notice
 *     and the following disclaimer in the documentation and/or other materials
 *     provided with the distribution.
 *
 *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
 *     contributors may be used to endorse or promote products derived from
 *     this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
 *
 * License 1.0
 */
package fr.paris.lutece.portal.service.spring;

import fr.paris.lutece.portal.service.init.LuteceInitException;
import fr.paris.lutece.portal.service.plugin.Plugin;
import fr.paris.lutece.portal.service.plugin.PluginEvent;
import fr.paris.lutece.portal.service.plugin.PluginEventListener;
import fr.paris.lutece.portal.service.plugin.PluginService;
import fr.paris.lutece.portal.service.util.AppLogService;
import fr.paris.lutece.portal.service.util.AppPathService;

import org.apache.commons.lang.StringUtils;

import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;

import org.springframework.web.context.support.GenericWebApplicationContext;

import java.io.File;
import java.io.FilenameFilter;

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;

/**
 * This class provides a way to use Spring Framework ligthweight containers
 * offering IoC (Inversion of Control) features.
 * @see <a href="http://www.springframework.org">http://www.springframework.org</a>
 */
public final class SpringContextService implements PluginEventListener {
    private static final String PATH_CONF = "/WEB-INF/conf/";
    private static final String DIR_PLUGINS = "plugins/";
    private static final String DIR_OVERRIDE = "override/";
    private static final String DIR_OVERRIDE_PLUGINS = DIR_OVERRIDE + DIR_PLUGINS;
    private static final String SUFFIX_CONTEXT_FILE = "_context.xml";
    private static final String FILE_CORE_CONTEXT = "core_context.xml";
    private static ApplicationContext _context;
    private static Map<Class, List> _mapBeansOfType = new HashMap<Class, List>();
    private static SpringContextService _instance = new SpringContextService();

    /** Creates a new instance of SpringContextService */
    private SpringContextService() {
    }

    /**
     * Return an instance, which may be shared or independent, of the given bean name.
     * This method allows a Spring BeanFactory to be used as a replacement for
     * the Singleton or Prototype design pattern.<br />
     * The bean is retreived from the main context defined in the WEB-INF/conf/core_context.xml.
     *
     * @param <T> the generic type
     * @param strName The bean's name
     * @return The instance of the bean
     */
    public static <T> T getBean(String strName) {
        return (T) _context.getBean(strName);
    }

    /**
     * Return an instance of the given bean name loaded by the a Spring BeanFactory.
     * The bean is retreived from a plugin context defined in the WEB-INF/conf/plugins/[plugin_name]_context.xml.
     * @param strPluginName The Plugin's name
     * @param strName The bean's name
     * @return The instance of the bean
     * @deprecated use {@link #getBean(String)} instead
     */
    @Deprecated
    public static Object getPluginBean(String strPluginName, String strName) {
        return _context.getBean(strName);
    }

    /**
     * Initialize a global Application Context containing all beans (core + plugins)
     * Now uses GenericApplicationContext for better performances. A wrong formatted file
     * will not block block context to be built (without the file), but a wrong bean (i.e. cannot
     * be instantiated) will cause a full context failure. Context is less "failure-friendly"
     * @param servletContext The servlet context
     * @throws LuteceInitException The lutece init exception
     * @since 2.4
     */
    public static void init(ServletContext servletContext) throws LuteceInitException {
        try {
            // Register this service as a PluginEventListener
            PluginService.registerPluginEventListener(_instance);

            // timing
            Date dateBegin = new Date();

            // Load the core context file : core_context.xml
            String strConfPath = AppPathService.getAbsolutePathFromRelativePath(PATH_CONF);
            String strContextFile = "file:" + strConfPath + FILE_CORE_CONTEXT;

            GenericWebApplicationContext gwac = new GenericWebApplicationContext(servletContext);
            gwac.setId(getContextName(servletContext));

            XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(gwac);
            xmlReader.loadBeanDefinitions(strContextFile);

            // _context = new ClassPathXmlApplicationContext( strContextFile );
            AppLogService.info("Context file loaded : " + FILE_CORE_CONTEXT);

            // Load all context files found in the conf/plugins directory
            // Files are loaded separatly with an individual try/catch block
            // to avoid stopping the process in case of a failure
            // The global context generation will fail if a bean in any file cannot be built.
            String strConfPluginsPath = strConfPath + DIR_PLUGINS;
            File dirConfPlugins = new File(strConfPluginsPath);
            FilenameFilter filterContext = new ContextFileFilter();
            String[] filesContext = dirConfPlugins.list(filterContext);

            loadContexts(filesContext, strConfPluginsPath, xmlReader);

            // we now load overriding beans
            AppLogService.info("Loading plugins context overrides");

            String strCoreContextOverrideFile = strConfPath + DIR_OVERRIDE + FILE_CORE_CONTEXT;
            File fileCoreContextOverride = new File(strCoreContextOverrideFile);

            if (fileCoreContextOverride.exists()) {
                AppLogService.debug("Context file loaded : core_context");
                xmlReader.loadBeanDefinitions("file:" + strCoreContextOverrideFile);
            } else {
                AppLogService.debug("No core_context override found");
            }

            // load plugins overrides
            String strConfPluginsOverridePath = strConfPath + DIR_OVERRIDE_PLUGINS;
            File dirConfOverridePlugins = new File(strConfPluginsOverridePath);

            if (dirConfOverridePlugins.exists()) {
                String[] filesOverrideContext = dirConfOverridePlugins.list(filterContext);
                loadContexts(filesOverrideContext, strConfPluginsOverridePath, xmlReader);
            }

            gwac.refresh();

            _context = gwac;

            AppLogService.info("Spring context loaded in " + (new Date().getTime() - dateBegin.getTime()) + "ms");
        } catch (Exception e) {
            AppLogService.error("Error initializing Spring Context Service " + e.getMessage(), e);
            throw new LuteceInitException("Error initializing Spring Context Service", e);
        }
    }

    /**
     * Returns a name for this context
     * @param servletContext the servlet context
     * @return name for this context
     */
    private static String getContextName(ServletContext servletContext) {
        String name = "lutece";

        if (servletContext != null) {
            String contextName = servletContext.getServletContextName();

            if (contextName == null) {
                contextName = servletContext.getContextPath();
            }

            if (StringUtils.isNotBlank(contextName)) {
                name = contextName;
            }
        }

        return name;
    }

    /**
     * Loads plugins contexts.
     * @param filesContext context files names
     * @param strConfPluginsPath full path
     * @param xmlReader the xml reader
     */
    private static void loadContexts(String[] filesContext, String strConfPluginsPath,
            XmlBeanDefinitionReader xmlReader) {
        for (String fileContext : filesContext) {
            String[] file = { "file:" + strConfPluginsPath + fileContext };

            // Safe loading of plugin context file
            try {
                //_context = new ClassPathXmlApplicationContext( file, _context );
                xmlReader.loadBeanDefinitions(file);
                AppLogService.info("Context file loaded : " + fileContext);
            } catch (Exception e) {
                AppLogService.error(
                        "Unable to load Spring context file : " + fileContext + " - cause : " + e.getMessage(), e);
            }
        }
    }

    /**
     * Gets the application context
     *
     * @return The application context
     */
    public static ApplicationContext getContext() {
        return _context;
    }

    /**
     * Returns a list of bean among all that implements a given interface or extends a given class
     * @param <T> The class type
     * @param classDef The class type
     * @return A list of beans
     */
    public static <T> List<T> getBeansOfType(Class<T> classDef) {
        // Search the list in the cache
        List<T> list = _mapBeansOfType.get(classDef);

        if (list != null) {
            return new ArrayList<T>(list);
        }

        // The list is not in the cache, so we have to build it
        list = new ArrayList<T>();

        Map<String, T> map = _context.getBeansOfType(classDef);
        String[] sBeanNames = map.keySet().toArray(new String[map.size()]);

        for (String strBeanName : sBeanNames) {
            String strPluginPrefix = getPrefix(strBeanName);

            if ((strPluginPrefix == null) || (isEnabled(strPluginPrefix))) {
                list.add(map.get(strBeanName));
            }
        }

        _mapBeansOfType.put(classDef, new ArrayList<T>(list));

        return list;
    }

    /**
     * Gets the prefix of the bean (supposed to be the plugin name)
     * @param strBeanName The bean name
     * @return The prefix
     */
    private static String getPrefix(String strBeanName) {
        int nPos = strBeanName.indexOf(".");

        if (nPos > 0) {
            return strBeanName.substring(0, nPos);
        }

        return null;
    }

    /**
     * Analyze a bean prefix to tell if it matchs an activated plugin
     * @param strPrefix The prefix of a bean
     * @return True if the prefix matchs an activated plugin
     */
    private static boolean isEnabled(String strPrefix) {
        Plugin plugin = PluginService.getPlugin(strPrefix);

        if ((plugin != null) && plugin.isInstalled()) {
            return true;
        }

        return false;
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public void processPluginEvent(PluginEvent event) {
        // Reset cache of beansOfType if a plugin is installed or uninstalled
        if ((event.getEventType() == PluginEvent.PLUGIN_INSTALLED)
                || (event.getEventType() == PluginEvent.PLUGIN_UNINSTALLED)) {
            if (!_mapBeansOfType.isEmpty()) {
                _mapBeansOfType.clear();
                AppLogService.info("SpringService cache cleared due to a plugin installation change - Plugin : "
                        + event.getPlugin().getName());
            }
        }
    }

    /**
     * Closes the Spring context
     * @since 5.1.0
     */
    public static void shutdown() {
        if (_context != null) {
            ((AbstractApplicationContext) _context).close();
        }
    }

    /**
     * Utils filename filter to identify context files
     */
    static class ContextFileFilter implements FilenameFilter {
        /**
         * Filter filename
         * @param file The current file
         * @param strName The file name
         * @return true if the file is a context file otherwise false
         */
        @Override
        public boolean accept(File file, String strName) {
            return strName.endsWith(SUFFIX_CONTEXT_FILE);
        }
    }
}