simplify InsertHistory

src/main/java/de/neemann/digital/gui/InsertHistory.java

@@ -10,21 +10,20 @@
 import de.neemann.digital.draw.library.LibraryNode;
 
 import javax.swing.*;
-import java.awt.event.ActionEvent;
 import java.util.ArrayList;
+import java.util.IdentityHashMap;
 import java.util.Iterator;
 
 /**
  * The InsertHistory puts the most frequently used elements to the toolbar of the main window.
- * So its easier to build circuits.
+ * So it's easier to build circuits.
  */
 public class InsertHistory implements LibraryListener {
     private static final int MAX_ICONS = 6;
     private final JToolBar bar;
+    private final ArrayList<InsertAction> actionsLRU;
+    private final IdentityHashMap<InsertAction, JComponent> components;
     private final ElementLibrary library;
-    private final ArrayList<WrapperAction> wrappers;
-    private int mainTime;
-    private InsertAction lastInsertAction;
 
     /**
      * Creates a new instance
@@ -35,63 +34,38 @@ public class InsertHistory implements LibraryListener {
     public InsertHistory(JToolBar bar, ElementLibrary library) {
         this.bar = bar;
         this.library = library;
-        wrappers = new ArrayList<>();
+        actionsLRU = new ArrayList<>();
+        components = new IdentityHashMap<>();
     }
 
     /**
      * Add an action to the toolbar.
-     * The given action is wrapped by an action which counts the usage.
-     * So its possible to remove the item which is not used the longest time when the toolbar becomes to large.
+     * The history of actions is kept in the least-recently-used (LRU) order.
+     * When the toolbar becomes too large, the oldest (LRU) action is removed.
      *
      * @param action the action
      */
     public void add(InsertAction action) {
-        lastInsertAction = action;
-        if (!contains(action)) {
-            WrapperAction wrapper = new WrapperAction(action, bar.getComponentCount());
-            wrappers.add(wrapper);
-            bar.add(wrapper).setToolTipText(action.getNode().getToolTipText());
-            if (wrappers.size() > MAX_ICONS) {
-                int oldest = findOldestIndex();
-                removeWrapperFromToolBar(wrappers.get(oldest));
-                wrappers.remove(oldest);
+        if (!actionsLRU.contains(action)) {
+            if (actionsLRU.size() >= MAX_ICONS) {
+                InsertAction oldest = actionsLRU.get(0);
+                bar.remove(components.get(oldest));
+                components.remove(oldest);
+                actionsLRU.remove(0);
             }
+            components.put(action, bar.add(action));
+        } else {
+            actionsLRU.remove(action);
         }
-    }
-
-    private void removeWrapperFromToolBar(WrapperAction wrapper) {
-        final int position = wrapper.componentPosition;
-        bar.remove(position);
-        for (WrapperAction w : wrappers)
-            if (w.componentPosition > position)
-                w.componentPosition--;
-    }
-
-    private int findOldestIndex() {
-        int found = -1;
-        int oldestTime = mainTime;
-        for (int i = 0; i < wrappers.size(); i++) {
-            WrapperAction wrapper = wrappers.get(i);
-            if (wrapper.time < oldestTime) {
-                found = i;
-                oldestTime = wrapper.time;
-            }
-        }
-        return found;
-    }
-
-    private boolean contains(InsertAction action) {
-        for (WrapperAction wrapper : wrappers)
-            if (wrapper.action.getName().equals(action.getName()))
-                return true;
-        return false;
+        actionsLRU.add(action);
     }
 
     /**
      * @return the last insert action
      */
     public InsertAction getLastInsertAction() {
-        return lastInsertAction;
+        if (!actionsLRU.isEmpty()) return actionsLRU.get(actionsLRU.size() - 1);
+        return null;
     }
 
     @Override
@@ -104,42 +78,18 @@ public void libraryChanged(LibraryNode node) {
      * If the component no longer exists, it is deleted from the history toolbar.
      */
     private void updateCustomComponents() {
-        Iterator<WrapperAction> it = wrappers.iterator();
+        Iterator<InsertAction> it = actionsLRU.iterator();
         while (it.hasNext()) {
-            WrapperAction w = it.next();
-            if (w.action.isCustom()) {
-                LibraryNode n = library.getElementNodeOrNull(w.action.getName());
-                if (n == null) {  // is'nt there, so delete
-                    removeWrapperFromToolBar(w);
-                    it.remove();
-                } else
-                    w.update(n);
+            InsertAction a = it.next();
+            if (a.isCustom()) {
+                LibraryNode n = library.getElementNodeOrNull(a.getName());
+                if (n == null) {  // isn't there, so delete
+                    bar.remove(components.get(a));  // removes from the toolbar
+                    components.remove(a);           // removes from components
+                    it.remove();                    // removes from actionsLRU
+                } else a.update(n);
             }
         }
         bar.revalidate();
     }
-
-    private final class WrapperAction extends AbstractAction {
-        private final InsertAction action;
-        private int componentPosition;
-        private int time;
-
-        private WrapperAction(InsertAction action, int componentPosition) {
-            super(action.getValue(Action.NAME).toString(), (Icon) action.getValue(Action.SMALL_ICON));
-            this.action = action;
-            this.componentPosition = componentPosition;
-            time = mainTime++;
-        }
-
-        @Override
-        public void actionPerformed(ActionEvent e) {
-            action.actionPerformed(e);
-            time = mainTime++;
-        }
-
-        public void update(LibraryNode n) {
-            action.update(n);
-            putValue(Action.SMALL_ICON, action.getValue(Action.SMALL_ICON));
-        }
-    }
 }