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

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Here is the source code for eu.esdihumboldt.hale.ui.service.project.internal.RecentFilesServiceImpl.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.util.Iterator;

import org.apache.commons.collections.buffer.CircularFifoBuffer;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.ui.IMemento;

import eu.esdihumboldt.hale.ui.service.project.RecentFilesService;

/**
 * This service saves a list of recently opened files.
 * 
 * @author Michel Kraemer
 */
public class RecentFilesServiceImpl implements RecentFilesService {

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

        private String file;
        private 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;
        }

        /**
         * Restores an entry from a given memento.
         * 
         * @param memento the memento
         */
        private EntryImpl(IMemento memento) {
            file = memento.getString(TAG_NAME);
            projectName = memento.getString(TAG_PROJECT_NAME);
        }

        /**
         * @see eu.esdihumboldt.hale.ui.service.project.RecentFilesService.Entry#getFile()
         */
        @Override
        public String getFile() {
            return file;
        }

        /**
         * @see eu.esdihumboldt.hale.ui.service.project.RecentFilesService.Entry#getProjectName()
         */
        @Override
        public String getProjectName() {
            return projectName;
        }

        /**
         * Saves an entry to the given memento.
         * 
         * @param memento the memento
         */
        private void saveEntry(IMemento memento) {
            memento.putString(TAG_NAME, file);
            memento.putString(TAG_PROJECT_NAME, projectName);
        }

        /**
         * @see java.lang.Object#equals(java.lang.Object)
         */
        @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;
        }

        /**
         * @see java.lang.Object#hashCode()
         */
        @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;

    /**
     * Tag for data sources stored in a memento
     */
    private static final String TAG_FILE = "file"; //$NON-NLS-1$
    private static final String TAG_NAME = "name"; //$NON-NLS-1$
    private static final String TAG_PROJECT_NAME = "projectName"; //$NON-NLS-1$

    /**
     * A circular buffer which saves the recent files
     */
    private CircularFifoBuffer _buffer = new CircularFifoBuffer(MAX_FILES);

    /**
     * @see RecentFilesService#add(String, String)
     */
    @Override
    public void add(String file, String projectName) {
        if (file != null) {
            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);
        }
    }

    /**
     * @see RecentFilesService#getRecentFiles()
     */
    @Override
    public Entry[] getRecentFiles() {
        Entry[] result = new Entry[_buffer.size()];
        int i = 0;
        for (Object o : _buffer)
            result[i++] = (Entry) o;
        return result;
    }

    /**
     * @see RecentFilesService#restoreState(IMemento)
     */
    @Override
    public IStatus restoreState(IMemento memento) {
        if (memento != null) {
            IMemento[] dsms = memento.getChildren(TAG_FILE);
            if (dsms != null) {
                for (IMemento dsm : dsms) {
                    Entry entry = new EntryImpl(dsm);
                    if (entry.getFile() != null)
                        _buffer.add(entry);
                }
            }
        }
        return Status.OK_STATUS;
    }

    /**
     * @see RecentFilesService#saveState(IMemento)
     */
    @Override
    public IStatus saveState(IMemento memento) {
        for (Object o : _buffer) {
            EntryImpl entry = (EntryImpl) o;
            IMemento c = memento.createChild(TAG_FILE);
            entry.saveEntry(c);
        }
        return Status.OK_STATUS;
    }
}