Merge pull request #154 from adangel:issue-153-swt-resource-not-disposed

Dispose rule priority images from general preferences page #154

Author: adangel

ReleaseNotes.md

@@ -16,6 +16,7 @@ This is a minor release.
 ### Fixed Issues
 
 *   [#150](https://github.com/pmd/pmd-eclipse-plugin/issues/150): Error executing command ReviewCode: java.util.regex.PatternSyntaxException: Illegal/unsupported escape sequence near index
+*   [#153](https://github.com/pmd/pmd-eclipse-plugin/issues/153): Not properly disposed SWT resource
 
 ### API Changes
 

net.sourceforge.pmd.eclipse.plugin/src/main/java/net/sourceforge/pmd/eclipse/ui/BasicTableLabelProvider.java

@@ -4,6 +4,9 @@
 
 package net.sourceforge.pmd.eclipse.ui;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.widgets.Table;
 
@@ -15,9 +18,10 @@
  */
 public class BasicTableLabelProvider extends AbstractTableLabelProvider {
 
-    private final ItemColumnDescriptor[] columns;
+    private final ItemColumnDescriptor<?, ?>[] columns;
+    private final List<Image> imagesToBeDisposed = new ArrayList<>();
 
-    public BasicTableLabelProvider(ItemColumnDescriptor[] theColumns) {
+    public BasicTableLabelProvider(ItemColumnDescriptor<?, ?>[] theColumns) {
         columns = theColumns;
     }
 
@@ -26,20 +30,32 @@ public boolean isLabelProperty(Object element, String property) {
     }
 
     public Image getColumnImage(Object element, int columnIndex) {
-
-        return columns[columnIndex].imageFor(element);
+        ItemColumnDescriptor itemColumnDescriptor = columns[columnIndex];
+        Image image = itemColumnDescriptor.imageFor(element);
+        if (image != null && itemColumnDescriptor.shouldImageBeDisposed()) {
+            imagesToBeDisposed.add(image);
+        }
+        return image;
     }
 
     public String getColumnText(Object element, int columnIndex) {
-
-        Object value = columns[columnIndex].textFor(element);
+        ItemColumnDescriptor itemColumnDescriptor = columns[columnIndex];
+        Object value = itemColumnDescriptor.textFor(element);
         return value == null ? null : value.toString();
     }
 
     public void addColumnsTo(Table table) {
-
-        for (ItemColumnDescriptor desc : columns) {
+        for (ItemColumnDescriptor<?, ?> desc : columns) {
             desc.buildTableColumn(table);
         }
     }
+
+    @Override
+    public void dispose() {
+        super.dispose();
+        for (Image image : imagesToBeDisposed) {
+            image.dispose();
+        }
+        imagesToBeDisposed.clear();
+    }
 }

net.sourceforge.pmd.eclipse.plugin/src/main/java/net/sourceforge/pmd/eclipse/ui/ItemColumnDescriptor.java

@@ -22,6 +22,7 @@ public class ItemColumnDescriptor<T extends Object, V extends Object> extends Ab
 
     private final ItemFieldAccessor<T, V> accessor;
     private final ValueFormatter[] formatters;
+    private boolean shouldImageBeDisposed;
 
     public ItemColumnDescriptor(String theId, String labelKey, int theAlignment, int theWidth, boolean resizableFlag,
             ItemFieldAccessor<T, V> theAccessor) {
@@ -36,6 +37,15 @@ public ItemColumnDescriptor(String theId, String labelKey, int theAlignment, int
         formatters = theFormatters;
     }
 
+    public ItemColumnDescriptor<T, V> disposeImage() {
+        shouldImageBeDisposed = true;
+        return this;
+    }
+
+    public boolean shouldImageBeDisposed() {
+        return shouldImageBeDisposed;
+    }
+
     public T valueFor(V item) {
         return accessor.valueFor(item);
     }

net.sourceforge.pmd.eclipse.plugin/src/main/java/net/sourceforge/pmd/eclipse/ui/priority/PriorityColumnUI.java

@@ -76,7 +76,7 @@ public Image imageFor(RulePriority priority) {
     // PriorityColumnDescriptor size = new PriorityColumnDescriptor("", StringKeys.PRIORITY_COLUMN_SIZE, SWT.RIGHT, 25,
     // true, sizeAcc);
     ItemColumnDescriptor<Image, RulePriority> IMAGE = new ItemColumnDescriptor<Image, RulePriority>("",
-            StringKeys.PRIORITY_COLUMN_SYMBOL, SWT.CENTER, 25, true, IMAGE_ACC);
+            StringKeys.PRIORITY_COLUMN_SYMBOL, SWT.CENTER, 25, true, IMAGE_ACC).disposeImage();
     // PriorityColumnDescriptor color = new PriorityColumnDescriptor("", StringKeys.PRIORITY_COLUMN_COLOR, SWT.RIGHT,
     // 25, true, colorAcc);
     // PriorityColumnDescriptor description = new PriorityColumnDescriptor("", StringKeys.PRIORITY_COLUMN_DESC,

net.sourceforge.pmd.eclipse.plugin/src/main/java/net/sourceforge/pmd/eclipse/ui/priority/PriorityDescriptor.java

@@ -224,7 +224,9 @@ private Image createImage(final int size) {
     }
 
     /**
-     * Gets the marker image in a specific size. The image is cached and reused.
+     * Gets the marker image in a specific size. The image is cached and reused while the PMD Plugin is
+     * active. It is disposed automatically, when the PMD Plugin is disposed.
+     *
      * @param size
      * @return
      */
@@ -242,7 +244,8 @@ public Image getImage(int size) {
      * the priority descriptor is changed, but not persisted yet. The cached image returned by
      * {@link #getAnnotationImage()} would not reflect that change and a preview is not possible.
      *
-     * <p>The image is not cached.
+     * <p>The image is not cached. The returned image must be disposed manually.
+     *
      * @return
      */
     public Image createImage() {