com.quinsoft.zeidon.standardoe.ApplicationList.java Source code

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Here is the source code for com.quinsoft.zeidon.standardoe.ApplicationList.java

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/**
This file is part of the Zeidon Java Object Engine (Zeidon JOE).
    
Zeidon JOE is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
Zeidon JOE 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 Lesser General Public License for more details.
    
You should have received a copy of the GNU Lesser General Public License
along with Zeidon JOE.  If not, see <http://www.gnu.org/licenses/>.
    
Copyright 2009-2015 QuinSoft
 */

package com.quinsoft.zeidon.standardoe;

import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.FilenameUtils;
import org.apache.commons.lang3.StringUtils;

import com.google.common.collect.ImmutableMap;
import com.quinsoft.zeidon.ObjectEngine;
import com.quinsoft.zeidon.Task;
import com.quinsoft.zeidon.UnknownApplicationException;
import com.quinsoft.zeidon.ZeidonException;
import com.quinsoft.zeidon.ZeidonLogger;
import com.quinsoft.zeidon.config.HomeDirectory;
import com.quinsoft.zeidon.utils.JoeUtils;
import com.quinsoft.zeidon.utils.PortableFileReader;
import com.quinsoft.zeidon.utils.PortableFileReader.PortableFileAttributeHandler;
import com.quinsoft.zeidon.utils.PortableFileReader.PortableFileEntityHandler.NullEntityHandler;

/**
 * @author DG
 *
 */
class ApplicationList {
    /**
     * List of applications loaded by the system.
     */
    private final ImmutableMap<String, ApplicationImpl> applications;
    private final HomeDirectory home;

    /**
     * Loads the list of applications from %ZEIDON%/zeidon.app
     */
    ApplicationList(HomeDirectory home, ZeidonLogger logger) {
        logger.info("Loading application list");

        this.home = home;
        Map<String, ApplicationImpl> apps = new HashMap<String, ApplicationImpl>();

        // First try loading the resources.
        ClassLoader classLoader = getClass().getClassLoader();
        if (classLoader == null)
            classLoader = ClassLoader.getSystemClassLoader();

        try {
            for (Enumeration<URL> element = classLoader.getResources("zeidon.app"); element.hasMoreElements();) {
                URL url = element.nextElement();
                logger.info("Loading applications from resource %s", url.getFile());
                InputStream stream = url.openStream();
                ApplicationHandler appHandler = new ApplicationHandler(apps);
                PortableFileReader.ReadPortableFile(stream, logger, appHandler);
            }
        } catch (Exception e) {
            throw ZeidonException.wrapException(e).appendMessage("Error while attempting to load zeidon.app");
        }

        if (!StringUtils.isBlank(home.getHomeDirectory())) {
            String filename = FilenameUtils.concat(home.getHomeDirectory(), "zeidon.app");
            try {
                InputStream inputStream = JoeUtils.getInputStream(null, filename,
                        logger.getClass().getClassLoader());
                if (inputStream == null)
                    logger.info("No zeidon.app found via ZEIDON_HOME.");
                else {
                    logger.info("Loading apps using ZEIDON_HOME (%s)/zeidon.app", home.getHomeDirectory());
                    ApplicationHandler appHandler = new ApplicationHandler(apps);
                    PortableFileReader.ReadPortableFile(inputStream, logger, appHandler);
                }
            } catch (Exception e) {
                throw ZeidonException.wrapException(e).prependFilename(filename);
            }
        }

        if (apps.size() == 0)
            throw new ZeidonException("No resources named zeidon.app found.");

        applications = ImmutableMap.copyOf(apps);
    }

    ApplicationImpl getApplication(Task task, String applicationName) throws UnknownApplicationException {
        if (applications.containsKey(applicationName.toLowerCase())) {
            ApplicationImpl app = applications.get(applicationName.toLowerCase());
            app.loadDomains(task);
            return app;
        }

        throw new UnknownApplicationException(applicationName);
    }

    List<ApplicationImpl> getList() {
        return new ArrayList<ApplicationImpl>(applications.values());
    }

    private class ApplicationHandler extends NullEntityHandler {
        private final Map<String, ApplicationImpl> appMap;

        public ApplicationHandler(Map<String, ApplicationImpl> appMap) {
            this.appMap = appMap;
        }

        @Override
        public PortableFileAttributeHandler createEntity(PortableFileReader reader, int level, long flags) {
            if (reader.getAttributeName().equals("ZEIDON"))
                return new SystemApplication(home.getHomeDirectory());

            return new ApplicationImpl(home.getHomeDirectory());
        }

        @Override
        public void endEntity(PortableFileReader reader, PortableFileAttributeHandler handler, int level) {
            ApplicationImpl app = (ApplicationImpl) handler;

            String appKey = app.getName().toLowerCase();

            // Check to see if we've already loaded the zeidon.app for this app.  We don't mind multiple
            // ZeidonSystem apps because the attribute values are hard-coded and can't change so overwriting
            // an existing value in the map doesn't harm anything.
            if (appMap.containsKey(appKey) && !ObjectEngine.ZEIDON_SYSTEM_APP_NAME.equals(app.getName()))
                throw new ZeidonException("Application '%s' is defined multiple times", app.getName());

            appMap.put(app.getName().toLowerCase(), app);
        }
    }
}