org.silverpeas.core.admin.component.PersonalComponentRegistry.java Source code

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Here is the source code for org.silverpeas.core.admin.component.PersonalComponentRegistry.java

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/*
 * Copyright (C) 2000 - 2018 Silverpeas
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * As a special exception to the terms and conditions of version 3.0 of
 * the GPL, you may redistribute this Program in connection with Free/Libre
 * Open Source Software ("FLOSS") applications as described in Silverpeas's
 * FLOSS exception. You should have received a copy of the text describing
 * the FLOSS exception, and it is also available here:
 * "http://www.silverpeas.org/docs/core/legal/floss_exception.html"
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.silverpeas.core.admin.component;

import org.apache.commons.io.FilenameUtils;
import org.silverpeas.core.SilverpeasRuntimeException;
import org.silverpeas.core.admin.component.model.PersonalComponent;
import org.silverpeas.core.initialization.Initialization;
import org.silverpeas.core.util.ServiceProvider;
import org.silverpeas.core.util.lang.SystemWrapper;

import javax.inject.Singleton;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Stream;

/**
 * A registry of Web Application Personal Components available in Silverpeas.
 * </p>
 * The {@code PersonalComponent} available in Silverpeas are defined by an XML descriptor located in
 * the
 * <code>SILVERPEAS_HOME/xmlcomponents</code> directory. The descriptors that must satisfy the XSD
 * <a href="http://www.silverpeas.org/xsd/component.xsd">component.xsd</a>. The PersonalComponent
 * instances are then constructed from their XML descriptor by the registry at initialization time
 * so that they are available by the core component management service.
 * @author mmoquillon
 */
@Singleton
public class PersonalComponentRegistry implements Initialization {

    private static final int MAX_DEPTH = 2;
    private static Map<String, PersonalComponent> componentsByName = new HashMap<>();

    PersonalComponentRegistry() {
    }

    /**
     * Get the directory where the personal component descriptors are stored.
     * @return the path to the directory
     */
    private static Path getPersonalComponentDescriptorHome() {
        SystemWrapper system = SystemWrapper.get();
        return Paths.get(system.getenv("SILVERPEAS_HOME"), "xmlcomponents", "personals");
    }

    private static PersonalComponent loadComponent(File descriptor) {
        try {
            JAXBContext context = JAXBContext.newInstance("org.silverpeas.core.admin.component.model");
            Unmarshaller unmarshaller = context.createUnmarshaller();
            try (InputStream in = new FileInputStream(descriptor)) {
                XMLInputFactory factory = XMLInputFactory.newFactory();
                return (unmarshaller.unmarshal(factory.createXMLStreamReader(in), PersonalComponent.class))
                        .getValue();
            }
        } catch (IOException | JAXBException | XMLStreamException e) {
            throw new SilverpeasRuntimeException(e.getMessage(), e);
        }
    }

    /**
     * Gets an instance of this PersonalComponentRegistry registry.
     * @return a PersonalComponentRegistry instance.
     */
    public static PersonalComponentRegistry get() {
        return ServiceProvider.getService(PersonalComponentRegistry.class);
    }

    /**
     * Initializes some resources required by the services or performs some initialization processes
     * at Silverpeas startup.
     * @throws Exception if an error occurs during the initialization process. In this case
     * the Silverpeas startup fails.
     */
    @Override
    public void init() throws Exception {
        Path descriptorHome = getPersonalComponentDescriptorHome();
        try (Stream<Path> paths = Files.find(descriptorHome, MAX_DEPTH, (p, a) -> p.toFile().isFile()
                && "xml".equalsIgnoreCase(FilenameUtils.getExtension(p.toString())))) {
            paths.forEach(p -> {
                PersonalComponent component = loadComponent(p.toFile());
                componentsByName.put(component.getName(), component);
            });
        }
    }

    /**
     * Gets the PersonalComponent instance registered under the specified name.
     * @param componentName the name of the Silverpeas personal component.
     * @return an optional PersonalComponent instance if such instance exists under the given name.
     */
    public Optional<PersonalComponent> getPersonalComponent(String componentName) {
        return Optional.ofNullable(componentsByName.get(componentName));
    }

    /**
     * Gets all the registered PersonalComponent instances indexed by their name.
     * @return a dictionary of the available PersonalComponent instances indexed by their name.
     */
    public Map<String, PersonalComponent> getAllPersonalComponents() {
        return Collections.unmodifiableMap(componentsByName);
    }
}