Fix available columns synchronization in data laboratory

modules/DesktopDataLaboratory/src/main/java/org/gephi/desktop/datalab/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.
-
-The contents of this file are subject to the terms of either the GNU
-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
-/cddl-1.0.txt and /gpl-3.0.txt. If applicable, add the following below the
-License Header, with the fields enclosed by brackets [] replaced by
-your own identifying information:
-"Portions Copyrighted [year] [name of copyright owner]"
-
-If you wish your version of this file to be governed by only the CDDL
-or only the GPL Version 3, indicate your decision by adding
-"[Contributor] elects to include this software in this distribution
-under the [CDDL or GPL Version 3] license." If you do not indicate a
-single choice of license, a recipient has the option to distribute
-your version of this file under either the CDDL, the GPL Version 3 or
-to extend the choice of license to its licensees as provided above.
-However, if you add GPL Version 3 code and therefore, elected the GPL
-Version 3 license, then the option applies only if the new code is
-made subject to such option by the copyright holder.
-
-Contributor(s):
-
-Portions Copyrighted 2011 Gephi Consortium.
+ 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.
+
+ The contents of this file are subject to the terms of either the GNU
+ 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
+ /cddl-1.0.txt and /gpl-3.0.txt. If applicable, add the following below the
+ License Header, with the fields enclosed by brackets [] replaced by
+ your own identifying information:
+ "Portions Copyrighted [year] [name of copyright owner]"
+
+ If you wish your version of this file to be governed by only the CDDL
+ or only the GPL Version 3, indicate your decision by adding
+ "[Contributor] elects to include this software in this distribution
+ under the [CDDL or GPL Version 3] license." If you do not indicate a
+ single choice of license, a recipient has the option to distribute
+ your version of this file under either the CDDL, the GPL Version 3 or
+ to extend the choice of license to its licensees as provided above.
+ However, if you add GPL Version 3 code and therefore, elected the GPL
+ Version 3 license, then the option applies only if the new code is
+ made subject to such option by the copyright holder.
+
+ Contributor(s):
+
+ Portions Copyrighted 2011 Gephi Consortium.
  */
 package org.gephi.desktop.datalab;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 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.
+ * 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 List<Column> availableColumns = new ArrayList<Column>();
+    private final Set<Column> availableColumns = new HashSet<Column>();
+    private final Set<Column> allKnownColumns = new HashSet<Column>();
     private final Table table;
 
     public AvailableColumnsModel(Table table) {
@@ -69,10 +75,11 @@ public class AvailableColumnsModel {
 
     /**
      * 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 boolean addAvailableColumn(Column column) {
+    public synchronized boolean addAvailableColumn(Column column) {
         if (canAddAvailableColumn()) {
             if (!availableColumns.contains(column)) {
                 availableColumns.add(column);
@@ -85,22 +92,24 @@ public class AvailableColumnsModel {
 
     /**
      * 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 boolean removeAvailableColumn(Column column) {
+    public synchronized boolean removeAvailableColumn(Column column) {
         return availableColumns.remove(column);
     }
 
     /**
      * Clear all available columns
      */
-    public void removeAllColumns() {
+    public synchronized void removeAllColumns() {
         availableColumns.clear();
     }
 
     /**
      * Indicates if more columns can be made available a the moment
+     *
      * @return
      */
     public boolean canAddAvailableColumn() {
@@ -109,37 +118,43 @@ public class AvailableColumnsModel {
 
     /**
      * Return available columns, sorted by index
-     * @return 
+     *
+     * @return
      */
     public Column[] getAvailableColumns() {
-        Collections.sort(availableColumns, new Comparator<Column>() {
-
-            @Override
-            public int compare(Column o1, Column o2) {
-                return o1.getIndex() - o2.getIndex();
+        List<Column> availableColumnsList = new ArrayList<Column>();
+        for (Column column : table) {
+            if(availableColumns.contains(column)){
+                availableColumnsList.add(column);
             }
-        });
-        return availableColumns.toArray(new Column[0]);
+        }
+        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 void syncronizeTableColumns(){
-        List<Column> availableColumnsCopy = new ArrayList<Column>(availableColumns);
+    public synchronized void syncronizeTableColumns() {
+        Set<Column> availableColumnsCopy = new HashSet<Column>(availableColumns);
         
-        for (Column column : availableColumnsCopy) {
-            if(!table.hasColumn(column.getId())){
-                removeAvailableColumn(column);
-            }
-        }
+        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) {
-            addAvailableColumn(column);
+
+            if (availableColumnsCopy.contains(column) || !allKnownColumns.contains(column)) {
+                allKnownColumns.add(column);
+
+                addAvailableColumn(column);
+            }
         }
     }
 }