AvailableColumnsModel.java

/*
 Copyright 2008-2010 Gephi
 Authors : Eduardo Ramos <eduramiba@gmail.com>
 Website : http://www.gephi.org

 This file is part of Gephi.

 DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 Copyright 2011 Gephi Consortium. All rights reserved.

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 General Public License Version 3 only ("GPL") or the Common
 Development and Distribution License("CDDL") (collectively, the
 "License"). You may not use this file except in compliance with the
 License. You can obtain a copy of the License at
 http://gephi.org/about/legal/license-notice/
 or /cddl-1.0.txt and /gpl-3.0.txt. See the License for the
 specific language governing permissions and limitations under the
 License.  When distributing the software, include this License Header
 Notice in each file and include the License files at
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 */
package org.gephi.desktop.datalab;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.gephi.graph.api.Column;
import org.gephi.graph.api.Table;

/**
 * Class to keep available state (in data laboratory) of the columns of a table of a workspace. Useful, but also necessary to limit the maximum number of available columns when there are a lot of
 * columns.
 *
 * @author Eduardo
 */
public class AvailableColumnsModel {

    private static final int MAX_AVAILABLE_COLUMNS = 20;
    private final Set<Column> availableColumns = new HashSet<>();
    private final Set<Column> allKnownColumns = new HashSet<>();
    private final Table table;

    public AvailableColumnsModel(Table table) {
        this.table = table;
    }

    public boolean isColumnAvailable(Column column) {
        return availableColumns.contains(column);
    }

    /**
     * Add a column as available if it can be added.
     *
     * @param column Column to add
     * @return True if the column was successfully added, false otherwise (no more columns can be available)
     */
    public synchronized boolean addAvailableColumn(Column column) {
        if (canAddAvailableColumn()) {
            if (!availableColumns.contains(column)) {
                availableColumns.add(column);
            }
            return true;
        } else {
            return false;
        }
    }

    /**
     * Remove an available column from the model if possible.
     *
     * @param column Column to make not available
     * @return True if the column could be removed
     */
    public synchronized boolean removeAvailableColumn(Column column) {
        return availableColumns.remove(column);
    }

    /**
     * Clear all available columns
     */
    public synchronized void removeAllColumns() {
        availableColumns.clear();
    }

    /**
     * Indicates if more columns can be made available a the moment
     *
     * @return
     */
    public boolean canAddAvailableColumn() {
        return availableColumns.size() < MAX_AVAILABLE_COLUMNS;
    }

    /**
     * Return available columns, sorted by index
     *
     * @return
     */
    public Column[] getAvailableColumns() {
        List<Column> availableColumnsList = new ArrayList<>();
        for (Column column : table) {
            if(availableColumns.contains(column)){
                availableColumnsList.add(column);
            }
        }
        return availableColumnsList.toArray(new Column[0]);
    }

    public int getAvailableColumnsCount() {
        return availableColumns.size();
    }

    /**
     * Syncronizes this AvailableColumnsModel to contain the table current columns, checking for deleted and new columns.
     */
    public synchronized void syncronizeTableColumns() {
        Set<Column> availableColumnsCopy = new HashSet<>(availableColumns);
        
        removeAllColumns();
        
        //Detect new columns and make them available by default:
        //Also keep existing available columns as available.
        
        //Note: We need to remove all columns and add them all again because there could be a new column with the same title but different index 
        //if the old one with the same title was removed, and we should not keep the old column with same title.
        for (Column column : table) {
            if (availableColumnsCopy.contains(column) || !allKnownColumns.contains(column)) {
                allKnownColumns.add(column);

                addAvailableColumn(column);
            }
        }
    }
}