code improvement

diylc/diylc-swing/src/org/diylc/swing/plugins/cloud/view/browser/CloudBrowserFrame.java

@@ -7,7 +7,6 @@ import java.awt.GridBagLayout;
 import java.awt.Insets;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
-import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
@@ -43,7 +42,6 @@ public class CloudBrowserFrame extends JFrame {
 
   private SearchHeaderPanel searchHeaderPanel;
   private ResultsScrollPanel resultsScrollPane;
-  private NavigationPanel navigationPanel;
 
   private IPlugInPort plugInPort;
   private CloudPresenter cloudPresenter;
@@ -135,15 +133,6 @@ public class CloudBrowserFrame extends JFrame {
       gbc.weighty = 1;
       gbc.fill = GridBagConstraints.BOTH;
       searchPanel.add(getResultsScrollPane(), gbc);
-
-//      gbc.anchor = GridBagConstraints.NORTHWEST;
-//      gbc.insets = new Insets(2, 2, 2, 2);
-//      gbc.gridx = 0;
-//      gbc.gridy++;
-//      gbc.fill = GridBagConstraints.BOTH;
-//      gbc.weighty = 0;
-//      gbc.gridwidth = 3;
-//      searchPanel.add(getNavigationPanel(), gbc);
     }
     return searchPanel;
   }
@@ -155,11 +144,11 @@ public class CloudBrowserFrame extends JFrame {
 
         @Override
         public void actionPerformed(ActionEvent e) {
-          setPageNumber(1);
+          CloudBrowserFrame.this.pageNumber = 1;
           CloudBrowserFrame.this.searchFor = getSearchHeaderPanel().getSearchText();
           CloudBrowserFrame.this.category = getSearchHeaderPanel().getCategory();
           CloudBrowserFrame.this.sort = getSearchHeaderPanel().getSorting();
-          getResultsScrollPane().clear();
+          getResultsScrollPane().startOver();
           search();
         }
       });
@@ -172,13 +161,13 @@ public class CloudBrowserFrame extends JFrame {
       resultsScrollPane = new ResultsScrollPanel(swingUI, this, plugInPort, new ILazyProvider<ProjectEntity>() {
 
         @Override
-        public void requestMore() {
+        public void requestMoreData() {
-          setPageNumber(CloudBrowserFrame.this.pageNumber + 1);
+          CloudBrowserFrame.this.pageNumber++;
           CloudBrowserFrame.this.search();
         }
 
         @Override
-        public boolean hasMore() {
+        public boolean hasMoreData() {
           return currentResults.size() == itemsPerPage;
         }
       });
@@ -203,54 +192,11 @@ public class CloudBrowserFrame extends JFrame {
       @Override
       public void complete(List<ProjectEntity> result) {
         CloudBrowserFrame.this.currentResults = result;
-        getResultsScrollPane().startBatch();
+        getResultsScrollPane().addData(result);
-
-        for (Iterator<ProjectEntity> i = result.iterator(); i.hasNext();) {
-          ProjectEntity project = i.next();
-          getResultsScrollPane().addProjectToDisplay(project);
-        }
-//        if (count == 0) {
-//          getResultsScrollPane().showNoMatches();
-//          count++;
-//        } else
-          getResultsScrollPane().finishBatch();
       }
     });
   }
 
-  private NavigationPanel getNavigationPanel() {
-    if (navigationPanel == null) {
-      navigationPanel = new NavigationPanel();
-      navigationPanel.getPrevPageButton().addActionListener(new ActionListener() {
-
-        @Override
-        public void actionPerformed(ActionEvent e) {
-          if (CloudBrowserFrame.this.pageNumber > 1) {
-            setPageNumber(CloudBrowserFrame.this.pageNumber - 1);
-            CloudBrowserFrame.this.search();
-          }
-        }
-      });
-
-      navigationPanel.getNextPageButton().addActionListener(new ActionListener() {
-
-        @Override
-        public void actionPerformed(ActionEvent e) {
-          if (CloudBrowserFrame.this.currentResults != null && !CloudBrowserFrame.this.currentResults.isEmpty()) {
-            setPageNumber(CloudBrowserFrame.this.pageNumber + 1);
-            CloudBrowserFrame.this.search();
-          }
-        }
-      });
-    }
-    return navigationPanel;
-  }
-
-  private void setPageNumber(int pageNumber) {
-    this.pageNumber = pageNumber;
-    getNavigationPanel().getPageLabel().setText("Page " + pageNumber);
-  }
-
   public <T extends Object> void executeBackgroundTask(final ITask<T> task) {
     getGlassPane().setVisible(true);
     SwingWorker<T, Void> worker = new SwingWorker<T, Void>() {

diylc/diylc-swing/src/org/diylc/swing/plugins/cloud/view/browser/ILazyProvider.java

@@ -1,9 +1,21 @@
 package org.diylc.swing.plugins.cloud.view.browser;
 
-
+/***
+ * Generic interface for dynamic data provider.
+ * 
+ * @author Branislav Stojkovic
+ *
+ * @param <T>
+ */
 public interface ILazyProvider<T> {
 
-  boolean hasMore();
+  /**
+   * @return true if there's potentially more data at the source
+   */
+  boolean hasMoreData();
 
-  void requestMore();
+  /**
+   * call to request more data. New data batch should be sent asynchronously to this function call.
+   */
+  void requestMoreData();
 }

diylc/diylc-swing/src/org/diylc/swing/plugins/cloud/view/browser/NavigationPanel.java

@@ -1,77 +0,0 @@
-package org.diylc.swing.plugins.cloud.view.browser;
-
-import java.awt.Color;
-import java.awt.Cursor;
-import java.awt.GridBagConstraints;
-import java.awt.GridBagLayout;
-import java.awt.Insets;
-
-import javax.swing.JButton;
-import javax.swing.JLabel;
-import javax.swing.JPanel;
-import javax.swing.SwingConstants;
-
-import org.diylc.images.IconLoader;
-
-public class NavigationPanel extends JPanel {
-
-  private static final long serialVersionUID = 1L;
-
-  private JButton prevPageButton;
-  private JButton nextPageButton;
-  private JLabel pageLabel;
-
-  public NavigationPanel() {
-    super(new GridBagLayout());
-
-    this.setBackground(Color.white);
-    GridBagConstraints gbc = new GridBagConstraints();
-    gbc.anchor = GridBagConstraints.SOUTHWEST;
-    gbc.insets = new Insets(2, 2, 2, 2);
-    gbc.gridx = 0;
-    gbc.weightx = 0;
-    gbc.fill = GridBagConstraints.NONE;
-    this.add(getPrevPageButton(), gbc);
-
-    gbc.gridx++;
-    gbc.weightx = 1;
-    gbc.anchor = GridBagConstraints.LINE_START;
-    gbc.fill = GridBagConstraints.HORIZONTAL;
-    this.add(getPageLabel(), gbc);
-
-    gbc.gridx++;
-    gbc.weightx = 0;
-    gbc.anchor = GridBagConstraints.SOUTHWEST;
-    gbc.fill = GridBagConstraints.NONE;
-    this.add(getNextPageButton(), gbc);
-  }
-
-  public JButton getPrevPageButton() {
-    if (prevPageButton == null) {
-      prevPageButton = new JButton(IconLoader.NavLeftBlue.getIcon());
-      prevPageButton.setBorderPainted(false);
-      prevPageButton.setContentAreaFilled(false);
-      prevPageButton.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
-    }
-    return prevPageButton;
-  }
-
-  public JButton getNextPageButton() {
-    if (nextPageButton == null) {
-      nextPageButton = new JButton(IconLoader.NavRightBlue.getIcon());
-      nextPageButton.setBorderPainted(false);
-      nextPageButton.setContentAreaFilled(false);
-      nextPageButton.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
-    }
-    return nextPageButton;
-  }
-
-  public JLabel getPageLabel() {
-    if (pageLabel == null) {
-      pageLabel = new JLabel();
-      pageLabel.setFont(pageLabel.getFont().deriveFont(12f));
-      pageLabel.setHorizontalAlignment(SwingConstants.CENTER);
-    }
-    return pageLabel;
-  }
-}

diylc/diylc-swing/src/org/diylc/swing/plugins/cloud/view/browser/ResultsScrollPanel.java

@@ -6,6 +6,7 @@ import java.awt.Graphics;
 import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.Insets;
+import java.awt.Point;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.awt.image.BufferedImage;
@@ -14,11 +15,13 @@ import java.io.FileOutputStream;
 import java.net.URL;
 import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
+import java.util.List;
 
 import javax.imageio.ImageIO;
 import javax.swing.Icon;
 import javax.swing.ImageIcon;
 import javax.swing.JButton;
+import javax.swing.JComponent;
 import javax.swing.JFrame;
 import javax.swing.JLabel;
 import javax.swing.JPanel;
@@ -44,17 +47,24 @@ public class ResultsScrollPanel extends JScrollPane {
   private static final Logger LOG = Logger.getLogger(ResultsScrollPanel.class);
 
   private JPanel resultsPanel;
+  /**
+   * This label goes at the end of the page. When it gets rendered we know that we need to request
+   * another page.
+   */
+  private JLabel loadMoreLabel;
 
   private ISwingUI mainUI;
   private CloudBrowserFrame cloudUI;
 
   private IPlugInPort plugInPort;
 
-  private boolean running;
+  private int currentLocation;
+  /**
+   * This flag tells us whether the loadMoreLabel should invoke a new data pull or not.
+   */
+  private boolean armed;
   private ILazyProvider<ProjectEntity> provider;
 
-  private int location;
-
   public ResultsScrollPanel(ISwingUI mainUI, CloudBrowserFrame cloudUI, IPlugInPort plugInPort,
       ILazyProvider<ProjectEntity> provider) {
     super();
@@ -68,9 +78,18 @@ public class ResultsScrollPanel extends JScrollPane {
     setViewportView(getResultsPanel());
   }
 
-  public void clear() {
+  public void startOver() {
+    currentLocation = 0;
     getResultsPanel().removeAll();
-    running = false;
+    armed = false;
+    GridBagConstraints gbc = new GridBagConstraints();
+    gbc.anchor = GridBagConstraints.NORTHWEST;
+    gbc.gridx = 0;
+    gbc.gridy = 10000;
+    gbc.fill = GridBagConstraints.BOTH;
+    gbc.weightx = 0;
+    gbc.weighty = 100;
+    resultsPanel.add(getLoadMoreLabel(), gbc);
   }
 
   public void showNoMatches() {
@@ -86,12 +105,19 @@ public class ResultsScrollPanel extends JScrollPane {
     getResultsPanel().add(label, gbc);
   }
 
-  public void startBatch() {
+  public void addData(List<ProjectEntity> projects) {
-    this.getResultsPanel().remove(getLastLabel());
+    if (projects == null || projects.isEmpty() && currentLocation == 0) {
-    this.running = true;
+      showNoMatches();
+    } else {
+      for (int i = 0; i < projects.size(); i++) {
+        addProjectToDisplay(projects.get(i));
+        this.currentLocation++;
+      }
+      armed = true;
+    }    
   }
 
-  public void addProjectToDisplay(final ProjectEntity project) {
+  private JComponent addProjectToDisplay(final ProjectEntity project) {
     JLabel thumbnailLabel = new JLabel(loadImage(project.getThumbnailUrl()));
     JLabel nameLabel = new JLabel("<html><b>" + project.getName() + "</b></html>");
     nameLabel.setFont(nameLabel.getFont().deriveFont(12f));
@@ -100,10 +126,6 @@ public class ResultsScrollPanel extends JScrollPane {
     descriptionArea.setFont(thumbnailLabel.getFont());
     descriptionArea.setLineWrap(true);
     descriptionArea.setWrapStyleWord(true);
-    // JLabel descriptionLabel = new JLabel("<html>" + project.getDescription() + "</html>");
-    // JScrollPane descriptionScroll = new JScrollPane(descriptionArea);
-    // descriptionScroll.setBorder(null);
-    // descriptionLabel.setMaximumSize(new Dimension(200, 100));
     JLabel categoryLabel = new JLabel("<html>Category: <b>" + project.getCategory() + "</b></html>");
     JLabel authorLabel = new JLabel("<html>Author: <b>" + project.getOwner() + "</b></html>");
     JLabel updatedLabel = new JLabel("<html>Last updated: <b>" + project.getUpdated() + "</b></html>");
@@ -178,7 +200,7 @@ public class ResultsScrollPanel extends JScrollPane {
     gbc.anchor = GridBagConstraints.NORTHWEST;
     gbc.insets = new Insets(2, 2, 2, 2);
     gbc.gridx = 0;
-    gbc.gridy = location * 6;
+    gbc.gridy = currentLocation * 6;
     gbc.fill = GridBagConstraints.NONE;
     gbc.gridheight = 5;
     gbc.weightx = 0;
@@ -231,35 +253,26 @@ public class ResultsScrollPanel extends JScrollPane {
     gbc.insets = new Insets(2, 2, 2, 2);
     getResultsPanel().add(new JSeparator(), gbc);
 
-    location++;
+    return thumbnailLabel;
   }
 
-  public void finishBatch() {
+  private JLabel getLoadMoreLabel() {
-    GridBagConstraints gbc = new GridBagConstraints();
+    if (loadMoreLabel == null) {
-    gbc.anchor = GridBagConstraints.NORTHWEST;
+      loadMoreLabel = new JLabel("Load more...") {
-    gbc.gridx = 0;
-    gbc.gridy = location * 6;
-    gbc.fill = GridBagConstraints.BOTH;
-    gbc.weightx = 0;
-    gbc.weighty = 100;
-    getResultsPanel().add(getLastLabel(), gbc);
-  }
 
-  private JLabel lastLabel;
+        private static final long serialVersionUID = 1L;
 
-  private JLabel getLastLabel() {
-    if (lastLabel == null) {
-      lastLabel = new JLabel("Load more...") {
         @Override
         public void paint(Graphics g) {
-          if (running && provider.hasMore()) {
+          if (armed && provider.hasMoreData()) {
-            running = false;
+            // disarm immediately so we don't trigger successive requests to the provider
-            provider.requestMore();
+            armed = false;
+            provider.requestMoreData();
           }
         }
       };
     }
-    return lastLabel;
+    return loadMoreLabel;
   }
 
   private JPanel getResultsPanel() {