Create a FileUtils class to simplify file opening/saving.

src/main/org/insa/graphics/MainWindow.java

@@ -19,7 +19,6 @@ import java.io.IOException;
 import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.prefs.Preferences;
 
 import javax.swing.BorderFactory;
 import javax.swing.Box;
@@ -42,7 +41,6 @@ import javax.swing.Timer;
 import javax.swing.UIManager;
 import javax.swing.border.CompoundBorder;
 import javax.swing.border.EmptyBorder;
-import javax.swing.filechooser.FileNameExtensionFilter;
 
 import org.insa.algo.AbstractSolution;
 import org.insa.algo.AlgorithmFactory;
@@ -70,6 +68,8 @@ import org.insa.graphics.drawing.Drawing;
 import org.insa.graphics.drawing.GraphPalette;
 import org.insa.graphics.drawing.components.BasicDrawing;
 import org.insa.graphics.drawing.components.MapViewDrawing;
+import org.insa.graphics.utils.FileUtils;
+import org.insa.graphics.utils.FileUtils.FolderType;
 
 public class MainWindow extends JFrame {
 
@@ -88,15 +88,6 @@ public class MainWindow extends JFrame {
      */
     private static final int THREAD_TIMER_DELAY = 1000; // in milliseconds
 
-    private static final String DEFAULT_MAP_FOLDER_KEY = "DefaultMapFolder";
-    private static final String DEFAULT_MAP_FOLDER_INSA = "/home/commetud/...";
-
-    private static final String DEFAULT_PATH_FOLDER_KEY = "DefaultPathFolder";
-    private static final String DEFAULT_PATH_FOLDER_INSA = "/home/commetud/...";
-
-    // Preferences
-    private Preferences preferences = Preferences.userRoot().node(getClass().getName());
-
     // Current graph.
     protected Graph graph;
 
@@ -303,25 +294,9 @@ public class MainWindow extends JFrame {
         ActionListener openMapActionListener = new ActionListener() {
             @Override
             public void actionPerformed(ActionEvent e) {
-                JFileChooser chooser = new JFileChooser();
+                JFileChooser chooser = FileUtils.createFileChooser(FolderType.Map);
-                FileNameExtensionFilter filter = new FileNameExtensionFilter("Graph files",
-                        "mapgr");
-                File mapFolder = new File(
-                        preferences.get(DEFAULT_MAP_FOLDER_KEY, DEFAULT_MAP_FOLDER_INSA));
-                if (!mapFolder.exists()) {
-                    mapFolder = new File(System.getProperty("user.dir"));
-                }
-                chooser.setCurrentDirectory(mapFolder);
-                chooser.setFileFilter(filter);
                 if (chooser.showOpenDialog(MainWindow.this) == JFileChooser.APPROVE_OPTION) {
                     graphFilePath = chooser.getSelectedFile().getAbsolutePath();
-
-                    // Check...
-                    if (chooser.getSelectedFile().exists()) {
-                        preferences.put(DEFAULT_MAP_FOLDER_KEY,
-                                chooser.getSelectedFile().getParent());
-                    }
-
                     DataInputStream stream;
                     try {
                         stream = new DataInputStream(new BufferedInputStream(
@@ -659,24 +634,8 @@ public class MainWindow extends JFrame {
 
             @Override
             public void actionPerformed(ActionEvent e) {
-                JFileChooser chooser = new JFileChooser();
+                JFileChooser chooser = FileUtils.createFileChooser(FolderType.PathInput);
-                FileNameExtensionFilter filter = new FileNameExtensionFilter(
-                        "Path & compressed path files", "path");
-                File pathFolder = new File(
-                        preferences.get(DEFAULT_PATH_FOLDER_KEY, DEFAULT_PATH_FOLDER_INSA));
-                if (!pathFolder.exists()) {
-                    pathFolder = new File(System.getProperty("user.dir"));
-                }
-                chooser.setCurrentDirectory(pathFolder);
-                chooser.setFileFilter(filter);
                 if (chooser.showOpenDialog(MainWindow.this) == JFileChooser.APPROVE_OPTION) {
-
-                    // Check & Update
-                    if (chooser.getSelectedFile().exists()) {
-                        preferences.put(DEFAULT_PATH_FOLDER_KEY,
-                                chooser.getSelectedFile().getParent());
-                    }
-
                     BinaryPathReader reader;
                     try {
                         reader = new BinaryPathReader(new DataInputStream(new BufferedInputStream(

src/main/org/insa/graphics/PathsPanel.java

@@ -37,6 +37,8 @@ import org.insa.graph.Path;
 import org.insa.graph.io.BinaryPathWriter;
 import org.insa.graphics.drawing.Drawing;
 import org.insa.graphics.drawing.overlays.PathOverlay;
+import org.insa.graphics.utils.FileUtils;
+import org.insa.graphics.utils.FileUtils.FolderType;
 
 public class PathsPanel extends JPanel implements DrawingChangeListener, GraphChangeListener {
 
@@ -216,18 +218,15 @@ public class PathsPanel extends JPanel implements DrawingChangeListener, GraphCh
             saveButton.addActionListener(new ActionListener() {
                 @Override
                 public void actionPerformed(ActionEvent e) {
-                    String filepath = System.getProperty("user.dir");
+                    String filepath = String.format("path_%s_%d_%d.path",
-                    filepath += File.separator + String.format("path_%s_%d_%d.path",
                             path.getGraph().getMapId().toLowerCase().replaceAll("[^a-z0-9_]", "_"),
                             path.getOrigin().getId(), path.getDestination().getId());
-                    JFileChooser fileChooser = new JFileChooser();
+                    JFileChooser chooser = FileUtils.createFileChooser(FolderType.PathOutput,
-                    fileChooser.setSelectedFile(new File(filepath));
+                            filepath);
-                    fileChooser.setApproveButtonText("Save");
-                    fileChooser.setToolTipText("Save");
 
-                    if (fileChooser
+                    if (chooser
                             .showSaveDialog(getTopLevelAncestor()) == JFileChooser.APPROVE_OPTION) {
-                        File file = fileChooser.getSelectedFile();
+                        File file = chooser.getSelectedFile();
                         try {
                             BinaryPathWriter writer = new BinaryPathWriter(new DataOutputStream(
                                     new BufferedOutputStream(new FileOutputStream(file))));
@@ -284,6 +283,7 @@ public class PathsPanel extends JPanel implements DrawingChangeListener, GraphCh
 
         /*
          * (non-Javadoc)
+         * 
          * @see java.lang.Object#toString()
          */
         public String toString() {

src/main/org/insa/graphics/utils/FileUtils.java

@@ -0,0 +1,111 @@
+package org.insa.graphics.utils;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.io.File;
+import java.util.EnumMap;
+import java.util.Map;
+import java.util.prefs.Preferences;
+
+import javax.swing.JFileChooser;
+import javax.swing.filechooser.FileFilter;
+import javax.swing.filechooser.FileNameExtensionFilter;
+
+public class FileUtils {
+
+    // Preferences
+    private static Preferences preferences = Preferences.userRoot().node(FileUtils.class.getName());
+
+    public enum FolderType {
+        Map, PathInput, PathOutput
+    }
+
+    private static class PreferencesEntry {
+        public String key;
+        public String value;
+
+        public PreferencesEntry(String key, String value) {
+            this.key = key;
+            this.value = value;
+        }
+    }
+
+    // Map folder type -> PreferencesEntry
+    private static final Map<FolderType, PreferencesEntry> folderToEntry = new EnumMap<>(
+            FolderType.class);
+
+    // Map folder type -> File Filter
+    private static final Map<FolderType, FileFilter> folderToFilter = new EnumMap<>(
+            FolderType.class);
+
+    static {
+        // Populate folderToEntry
+        folderToEntry.put(FolderType.Map,
+                new PreferencesEntry("DefaultMapFolder", "/home/commetud/..."));
+        folderToEntry.put(FolderType.PathInput,
+                new PreferencesEntry("DefaultPathInputFolder", "/home/commetud/..."));
+        folderToEntry.put(FolderType.PathOutput,
+                new PreferencesEntry("DefaultPathOutputsFolder", "paths"));
+
+        // Populate folderToFilter
+        folderToFilter.put(FolderType.Map, new FileNameExtensionFilter("Graph files", "mapgr"));
+        folderToFilter.put(FolderType.PathInput, new FileNameExtensionFilter("Path files", "path"));
+        folderToFilter.put(FolderType.PathOutput,
+                new FileNameExtensionFilter("Path files", "path"));
+    }
+
+    /**
+     * @return A File instance pointing to the preferred folder for the given type.
+     */
+    public static File getPreferredFolder(FolderType folderType) {
+        PreferencesEntry entry = folderToEntry.get(folderType);
+        File folder = new File(preferences.get(entry.key, entry.value));
+        if (!folder.exists()) {
+            folder = new File(System.getProperty("user.dir"));
+        }
+        return folder;
+    }
+
+    public static void updatePreferredFolder(FolderType folderType, File newPreferredFolder) {
+        PreferencesEntry entry = folderToEntry.get(folderType);
+        preferences.put(entry.key, newPreferredFolder.getAbsolutePath());
+    }
+
+    /**
+     * @return A FileFilter corresponding to input graph files.
+     */
+    public static FileFilter getFileFilter(FolderType folderType) {
+        return folderToFilter.get(folderType);
+    }
+
+    /**
+     * @param folderType
+     * @return
+     */
+    public static JFileChooser createFileChooser(FolderType folderType, String defaultFileName) {
+        JFileChooser chooser = new JFileChooser();
+        chooser.setCurrentDirectory(getPreferredFolder(folderType));
+        if (defaultFileName != null) {
+            chooser.setSelectedFile(new File(chooser.getCurrentDirectory().getAbsolutePath()
+                    + File.separator + defaultFileName));
+        }
+        chooser.setFileFilter(getFileFilter(folderType));
+        chooser.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                if (e.getActionCommand().equals(JFileChooser.APPROVE_SELECTION)) {
+                    if (chooser.getSelectedFile().exists()) {
+                        updatePreferredFolder(folderType,
+                                chooser.getSelectedFile().getParentFile());
+                    }
+                }
+            }
+        });
+        return chooser;
+    }
+
+    public static JFileChooser createFileChooser(FolderType folderType) {
+        return createFileChooser(folderType, null);
+    }
+
+}