Fridge: show initial letters in magnet bag when needed.

src/server/gwt/src/se/chalmers/cs/gf/gwt/client/FridgeBagPanel.java

@@ -1,8 +1,14 @@
 package se.chalmers.cs.gf.gwt.client;
 
+import java.util.LinkedHashSet;
+
 import com.google.gwt.core.client.GWT;
+import com.google.gwt.user.client.ui.Button;
+import com.google.gwt.user.client.ui.ClickListener;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.FlowPanel;
+import com.google.gwt.user.client.ui.VerticalPanel;
+import com.google.gwt.user.client.ui.Widget;
 
 public class FridgeBagPanel extends Composite {
 
@@ -12,13 +18,25 @@ public class FridgeBagPanel extends Composite {
 
 	private JSONRequest completeRequest = null;
 
+	private FlowPanel prefixPanel;
+
 	private FlowPanel mainPanel; 
 
+	private int maxMagnets = 100;
+
+	private LinkedHashSet<String> prefixes = new LinkedHashSet<String>();
+
+
 	public FridgeBagPanel (PGFWrapper pgf, MagnetFactory magnetFactory) {
 		this.pgf = pgf;
 		this.magnetFactory = magnetFactory;
+		prefixPanel = new FlowPanel();
 		mainPanel = new FlowPanel();
-		initWidget(mainPanel);
+		VerticalPanel vPanel = new VerticalPanel();
+		vPanel.setHorizontalAlignment(VerticalPanel.ALIGN_CENTER);
+		vPanel.add(prefixPanel);
+		vPanel.add(mainPanel);
+		initWidget(vPanel);
 		setStylePrimaryName("my-FridgeBagPanel");
 	}
 
@@ -27,11 +45,13 @@ public class FridgeBagPanel extends Composite {
 	}
 
 	public void updateBag (final String text, String prefix) {
-		mainPanel.clear();
-		int limit = 100;
 		if (completeRequest != null) {
 			completeRequest.cancel();
 		}
+		final boolean updatePrefixes = prefix.equals("");
+		mainPanel.clear();
+		if (updatePrefixes) { clearPrefixes(); }
+	    int limit = updatePrefixes ? 0 : maxMagnets; 
 		completeRequest = pgf.complete(text + " " + prefix, 
 				limit, new PGF.CompleteCallback() {
 			public void onResult(PGF.Completions completions) {
@@ -41,8 +61,17 @@ public class FridgeBagPanel extends Composite {
 						String[] words = newText.split("\\s+");
 						if (words.length > 0) {
 							String word = words[words.length - 1];
+							if (word.length() > 0) {
+								if (updatePrefixes) {
+									addPrefix(text, word.substring(0,1));
+								}
+								if (mainPanel.getWidgetCount() < maxMagnets) {
 									Magnet magnet = magnetFactory.createMagnet(word, completion.getFrom());
 									mainPanel.add(magnet);
+								} else {
+									prefixPanel.setVisible(true);
+								}
+							}
 						}
 					}
 				}
@@ -54,6 +83,24 @@ public class FridgeBagPanel extends Composite {
 		});
 	}
 
+	protected void clearPrefixes () {
+		prefixes.clear();
+		prefixPanel.clear();
+		prefixPanel.setVisible(false);
+	}
+
+	protected void addPrefix(final String text, final String prefix) {
+		if (prefixes.add(prefix)) {
+			Button prefixButton = new Button(prefix, new ClickListener() {		
+				public void onClick(Widget sender) {
+					updateBag(text, prefix);
+				}
+			});
+			prefixPanel.add(prefixButton);
+		}
+	}
+
+
 	/*
 	public void cloneMagnet (Magnet magnet) {
 		int i = getWidgetIndex(magnet);

src/server/gwt/src/se/chalmers/cs/gf/gwt/client/PGF.java

@@ -97,7 +97,7 @@ public class PGF {
 		args.add(new Arg("input", input));
 		args.add(new Arg("from", fromLang));
 		args.add(new Arg("cat", cat));
-		if (limit != -1) {
+		if (limit > 0) {
 			args.add(new Arg("limit", limit));
 		}
 		return sendGrammarRequest(pgfName, "complete", args, callback);