net.sourceforge.ganttproject.document.DocumentsMRU.java Source code

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Here is the source code for net.sourceforge.ganttproject.document.DocumentsMRU.java

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/*
GanttProject is an opensource project management tool.
Copyright (C) 2003-2011 Michael Haeusler, GanttProject Team
    
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 3
of the License, or (at your option) any later version.
    
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 General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package net.sourceforge.ganttproject.document;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import com.google.common.collect.Lists;

/**
 * List of Documents MRU (<b>M</b>ost <b>R</b>ecently <b>U</b>sed)
 *
 * @author Michael Haeusler (michael at akatose.de)
 */
public class DocumentsMRU {

    private int maxSize;

    private List<String> documents;

    private final ArrayList<DocumentMRUListener> myListeners = new ArrayList<DocumentMRUListener>();

    interface Listener {
        void MRUChanged();
    }

    public DocumentsMRU(int maxSize) {
        assert maxSize > 0 : "maxSize must be larger than zero (" + maxSize + ")";
        this.maxSize = maxSize;
        documents = Lists.newArrayListWithExpectedSize(maxSize);
    }

    /**
     * Adds a Document at the top of the list of Documents MRU. If the list is
     * already full, an old entry is removed, to make place for this new document.
     *
     * @param document
     *          the Document that should be added
     * @return true when the list has changed through the addition
     */
    public boolean add(String document, boolean toHead) {
        //    // if the document is invalid, we don't add it
        //    if (!document.isValidForMRU())
        //      return false;

        int i = documents.indexOf(document);
        // if the document is already on the top,
        // nothing needs to change.
        if (0 == i)
            return false;

        if (0 < i) {
            documents.remove(i);
        } else {
            while (documents.size() >= maxSize) {
                documents.remove(maxSize - 1);
            }
        }
        if (toHead) {
            documents.add(0, document);
        } else {
            documents.add(document);
        }
        fireMRUListChanged();

        return true;
    }

    /** clears the list of Documents MRU */
    public void clear() {
        documents.clear();
        fireMRUListChanged();
    }

    /** @return an Iterator over the entries of the list of Documents MRU */
    public Iterator<String> iterator() {
        return documents.iterator();
    }

    public void addListener(DocumentMRUListener listener) {
        myListeners.add(listener);
        // Fire event for listener to give it a possibility on getting access to the
        // current MRU list
        listener.mruListChanged(Collections.unmodifiableCollection(documents));
    }

    private void fireMRUListChanged() {
        Collection<String> unmodifiableCollection = Collections.unmodifiableCollection(documents);
        for (int i = 0; i < myListeners.size(); i++) {
            DocumentMRUListener next = myListeners.get(i);
            next.mruListChanged(unmodifiableCollection);
        }
    }
}