on-demand fetching UI side

gui/griffon-app/controllers/com/muwire/gui/BrowseController.groovy

@@ -24,6 +24,7 @@ import com.muwire.core.search.UIResultBatchEvent
 import com.muwire.core.search.UIResultEvent
 
 import javax.swing.JTextField
+import javax.swing.tree.TreePath
 
 @ArtifactProviderFor(GriffonController)
 class BrowseController {
@@ -126,7 +127,7 @@ class BrowseController {
         for(BrowseStatusEvent event : statusCopy) {
             model.status = event.status
             if(event.status == BrowseStatus.FETCHING) {
-                model.currentBatch = event.currentItems
+                model.currentBatch += event.currentItems
                 model.totalResults = event.totalResults
             }
         }
@@ -221,4 +222,10 @@ class BrowseController {
         
         mvcGroup.createMVCGroup("view-profile", uuid.toString(), params)
     }
+    
+    void requestFetch(TreePath treePath, boolean recursive) {
+        List<String> path = model.resultsTreeModel.getPathFromRoot(treePath)
+        if (path != null)
+            model.session.fetch(path, recursive)
+    } 
 }

gui/griffon-app/views/com/muwire/gui/BrowseView.groovy

@@ -10,6 +10,8 @@ import javax.swing.JTable
 import javax.swing.JTextField
 import javax.swing.JTree
 import javax.swing.KeyStroke
+import javax.swing.event.TreeExpansionEvent
+import javax.swing.event.TreeExpansionListener
 import javax.swing.tree.TreePath
 import java.awt.event.ActionEvent
 import java.awt.event.KeyEvent
@@ -55,6 +57,8 @@ class BrowseView {
     
     def sequentialDownloadCheckbox
     
+    private boolean onDemandExpansionRegistered
+    
     void initUI() {
         int rowHeight = application.context.get("row-height")
         int treeRowHeight = application.context.get("tree-row-height")
@@ -330,11 +334,13 @@ class BrowseView {
         Set<TreePath> expanded = new HashSet<>(treeExpansions.expandedPaths)
         model.resultsTreeModel.nodeStructureChanged(model.root)
         if (model.session == null && !model.session.supportsIncremental()) {
-            if (treeExpansions.manualExpansion)
-                expanded.each { tree.expandPath(it) }
-            else
-                TreeUtil.expand(tree)
+            TreeUtil.expand(tree)
+        } else if (!onDemandExpansionRegistered) {
+            onDemandExpansionRegistered = true
+            tree.addTreeExpansionListener(new OnDemandTreeExpansion())
         }
+        if (treeExpansions.manualExpansion)
+            expanded.each { tree.expandPath(it) }
         tree.setSelectionPaths(selectedPaths)
     }
     
@@ -416,4 +422,16 @@ class BrowseView {
                 controller.displayBatchedResults()
         }
     }
+    
+    private class OnDemandTreeExpansion implements TreeExpansionListener {
+
+        @Override
+        void treeExpanded(TreeExpansionEvent event) {
+            controller.requestFetch(event.getPath(), false)
+        }
+
+        @Override
+        void treeCollapsed(TreeExpansionEvent event) {
+        }
+    }
 }

gui/src/main/groovy/com/muwire/gui/ResultTreeModel.groovy

@@ -7,6 +7,7 @@ import javax.swing.tree.DefaultMutableTreeNode
 import javax.swing.tree.DefaultTreeModel
 import javax.swing.tree.MutableTreeNode
 import javax.swing.tree.TreeNode
+import javax.swing.tree.TreePath
 import java.text.Collator
 
 class ResultTreeModel extends DefaultTreeModel {
@@ -31,7 +32,8 @@ class ResultTreeModel extends DefaultTreeModel {
                 elementNode = new MutableResultNode()
                 elementNode.setUserObject(nodeData)
                 node.addDescendant(elementNode)
-            }
+            } else
+                removePlaceholder(elementNode)
             node = elementNode
         }
      
@@ -59,16 +61,46 @@ class ResultTreeModel extends DefaultTreeModel {
                 elementNode = new MutableResultNode()
                 elementNode.setUserObject(nodeData)
                 node.addDescendant(elementNode)
+            } else {
+                removePlaceholder(elementNode)
             }
             elementNode.getUserObject().addResult(event)
             node = elementNode
         }
 
         def fileNode = new MutableResultNode(event)
+        removePlaceholder(node)
+        node.addDescendant(fileNode)
+    }
+    
+    private static void removePlaceholder(SortedTreeNode node) {
         TreeNode placeHolder = node.getByKey(ResultTreeRenderer.PLACEHOLDER)
         if (placeHolder != null)
             node.remove(placeHolder)
-        node.addDescendant(fileNode)
+    }
+    
+    List<String> getPathFromRoot(TreePath treePath) {
+        
+        MutableResultNode last = (MutableResultNode)treePath.getLastPathComponent()
+        if (last.getChildCount() != 1)
+            return null
+        if (!(last.getChildAt(0) instanceof PlaceholderNode))
+            return null
+        
+        Object [] objects = treePath.getPath()
+        
+        List<String> rv = new ArrayList<>()
+        String hiddenRoot = null
+        for (int i = 1; i < objects.length; i++) {
+            Object userObject = objects[i].getUserObject()
+            if (userObject instanceof ResultTreeRenderer.ResultTreeNode) {
+                hiddenRoot = userObject.getHiddenRoot()
+                rv << userObject.toString()
+            }
+        }
+        
+        rv.add(0, hiddenRoot)
+        rv
     }
     
     static class MutableResultNode extends SortedTreeNode<UIResultEvent> {

gui/src/main/groovy/com/muwire/gui/ResultTreeRenderer.groovy

@@ -94,6 +94,10 @@ class ResultTreeRenderer extends DefaultTreeCellRenderer {
             element
         }
         
+        String getHiddenRoot() {
+            hiddenRoot
+        }
+        
         void addResult(UIResultEvent event) {
             files++
             size += event.size