eu.esdihumboldt.hale.ui.service.project.internal.RecentProjectsServiceImpl.java Source code

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Here is the source code for eu.esdihumboldt.hale.ui.service.project.internal.RecentProjectsServiceImpl.java

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/*
 * Copyright (c) 2012 Data Harmonisation Panel
 * 
 * All rights reserved. This program and the accompanying materials are made
 * available 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.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     HUMBOLDT EU Integrated Project #030962
 *     Data Harmonisation Panel <http://www.dhpanel.eu>
 */

package eu.esdihumboldt.hale.ui.service.project.internal;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.collections.buffer.CircularFifoBuffer;
import org.osgi.service.prefs.PreferencesService;

import com.google.common.base.Splitter;

import de.fhg.igd.osgi.util.OsgiUtils;
import de.fhg.igd.slf4jplus.ALogger;
import de.fhg.igd.slf4jplus.ALoggerFactory;
import eu.esdihumboldt.hale.ui.service.project.RecentProjectsService;

/**
 * This service saves a list of recently opened files.
 * 
 * @author Michel Kraemer
 * @author Simon Templer
 */
public class RecentProjectsServiceImpl implements RecentProjectsService {

    private static final ALogger log = ALoggerFactory.getLogger(RecentProjectsServiceImpl.class);

    /**
     * @see eu.esdihumboldt.hale.ui.service.project.RecentProjectsService.Entry
     * @author Kai Schwierczek
     */
    public static class EntryImpl implements Entry {

        private final String file;
        private final String projectName;

        /**
         * Creates an entry with the given data.
         * 
         * @param file the file name
         * @param projectName the project name
         */
        private EntryImpl(String file, String projectName) {
            this.file = file;
            this.projectName = projectName;
        }

        @Override
        public String getFile() {
            return file;
        }

        @Override
        public String getProjectName() {
            return projectName;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj != null && obj instanceof Entry) {
                Entry entry = (Entry) obj;
                // projectName can change, it's the same entry.
                if (this.file == null)
                    return entry.getFile() == null;
                else
                    return this.file.equals(entry.getFile());
            }
            return false;
        }

        @Override
        public int hashCode() {
            if (file == null)
                return 0;
            return file.hashCode();
        }
    }

    /**
     * The maximum number of files in the history
     */
    public static final int MAX_FILES = 6;

    private static final String CONFIG_PROPERTY = "hale.recentProjects"; //$NON-NLS-1$
    private static final String ENC = "UTF-8"; //$NON-NLS-1$

    /**
     * @see RecentProjectsService#add(String, String)
     */
    @Override
    public void add(String file, String projectName) {
        if (file != null) {
            CircularFifoBuffer buffer = restoreState();

            if (projectName == null)
                projectName = "";
            Entry entry = new EntryImpl(file, projectName);
            Iterator<?> i = buffer.iterator();
            while (i.hasNext()) {
                Entry rfe = (Entry) i.next();
                if (entry.equals(rfe)) {
                    i.remove();
                    break;
                }
            }
            buffer.add(entry);

            saveState(buffer);
        }
    }

    @Override
    public Entry[] getRecentFiles() {
        CircularFifoBuffer buffer = restoreState();

        Entry[] result = new Entry[buffer.size()];
        int i = 0;
        for (Object o : buffer)
            result[i++] = (Entry) o;
        return result;
    }

    private CircularFifoBuffer restoreState() {
        PreferencesService prefs = OsgiUtils.getService(PreferencesService.class);

        CircularFifoBuffer buffer = new CircularFifoBuffer(MAX_FILES);
        String configString = prefs.getSystemPreferences().get(CONFIG_PROPERTY, "");

        List<String> parts = Splitter.on(' ').splitToList(configString);

        buffer.clear();
        for (int i = 0; i < parts.size() - 1; i += 2) {
            try {
                String name = URLDecoder.decode(parts.get(i), ENC);
                String filename = URLDecoder.decode(parts.get(i + 1), ENC);

                Entry entry = new EntryImpl(filename, name);
                buffer.add(entry);
            } catch (UnsupportedEncodingException e) {
                log.error(ENC + "? That's supposed to be an encoding?", e);
            }
        }
        return buffer;
    }

    private void saveState(CircularFifoBuffer buffer) {
        PreferencesService prefs = OsgiUtils.getService(PreferencesService.class);

        StringBuilder configString = new StringBuilder();
        boolean first = true;
        for (Object o : buffer) {
            try {
                Entry entry = (Entry) o;
                if (first)
                    first = false;
                else
                    configString.append(' ');
                configString.append(URLEncoder.encode(entry.getProjectName(), ENC));
                configString.append(' ');
                configString.append(URLEncoder.encode(entry.getFile(), ENC));
            } catch (UnsupportedEncodingException e) {
                log.error(ENC + "? That's supposed to be an encoding?", e);
            }
        }

        prefs.getSystemPreferences().put(CONFIG_PROPERTY, configString.toString());
    }
}