TEIIDDES-1472 Need look-ahead when selecting Runtime Type value for a…

…n extension property in MED Editor

Installed a look-ahead proposal provider for the runtime type and for the translation (locale) combos. These
look-ahead proposals work when the combo has keyboard focus. Selection is changed to the proposal if the CR
key is hit.

plugins/org.teiid.designer.extension.ui/src/org/teiid/designer/extension/ui/editors/CComboProposalProvider.java

@@ -0,0 +1,231 @@
+/*
+ * JBoss, Home of Professional Open Source.
+*
+* See the LEGAL.txt file distributed with this work for information regarding copyright ownership and licensing.
+*
+* See the AUTHORS.txt file distributed with this work for a full listing of individual contributors.
+*/
+package org.teiid.designer.extension.ui.editors;
+
+import java.util.List;
+import org.eclipse.jface.fieldassist.ContentProposal;
+import org.eclipse.jface.fieldassist.ContentProposalAdapter;
+import org.eclipse.jface.fieldassist.IContentProposal;
+import org.eclipse.jface.fieldassist.IContentProposalProvider;
+import org.eclipse.jface.fieldassist.IControlContentAdapter;
+import org.eclipse.jface.fieldassist.IControlContentAdapter2;
+import org.eclipse.jface.util.Util;
+import org.eclipse.swt.custom.CCombo;
+import org.eclipse.swt.events.KeyAdapter;
+import org.eclipse.swt.events.KeyEvent;
+import org.eclipse.swt.graphics.GC;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.swt.graphics.Rectangle;
+import org.eclipse.swt.widgets.Control;
+import org.teiid.designer.core.util.StringUtilities;
+
+/**
+ * Provides matching CCombo items based on keystrokes for a readonly combo.
+ */
+abstract class CComboProposalProvider implements IControlContentAdapter, IControlContentAdapter2, IContentProposalProvider {
+
+    private static final long DEFAULT_DURATION = 500;
+
+    private final CCombo combo;
+    private long duration = DEFAULT_DURATION;
+    private String pattern = StringUtilities.EMPTY_STRING;
+    private long t1 = System.currentTimeMillis();
+    private long t2;
+
+    /**
+     * @param combo the combo whose proposals are being requested (cannot be <code>null</code>)
+     */
+    protected CComboProposalProvider(final CCombo combo) {
+        this(combo, DEFAULT_DURATION);
+    }
+
+    /**
+     * @param combo the combo whose proposals are being requested (cannot be <code>null</code>)
+     * @param duration the amount of time to wait before resetting the pattern used to match items
+     */
+    protected CComboProposalProvider(final CCombo combo,
+                                     final long duration) {
+        this.duration = duration;
+        this.combo = combo;
+        combo.addKeyListener(new KeyAdapter() {
+
+            /**
+             * @see org.eclipse.swt.events.KeyAdapter#keyPressed(org.eclipse.swt.events.KeyEvent)
+             */
+            @Override
+            public void keyPressed(KeyEvent e) {
+                handleKeyPressed(e);
+            }
+        });
+    }
+
+    /**
+     * @return the characters that trigger auto-activation of proposals (can be <code>null</code>)
+     */
+    protected abstract char[] getActivationChars();
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#getControlContents(org.eclipse.swt.widgets.Control)
+     */
+    @Override
+    public final String getControlContents(final Control control) {
+        return this.combo.getText();
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#getCursorPosition(org.eclipse.swt.widgets.Control)
+     */
+    @Override
+    public final int getCursorPosition(final Control control) {
+        return this.combo.getSelection().x;
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#getInsertionBounds(org.eclipse.swt.widgets.Control)
+     */
+    @Override
+    public final Rectangle getInsertionBounds(final Control control) {
+        final int position = this.combo.getSelection().y;
+        final String contents = this.combo.getText();
+
+        final GC gc = new GC(this.combo);
+        gc.setFont(this.combo.getFont());
+
+        final Point extent = gc.textExtent(contents.substring(0, Math.min(position, contents.length())));
+        gc.dispose();
+
+        return new Rectangle(this.combo.getClientArea().x + extent.x, this.combo.getClientArea().y, 1,
+                             this.combo.getClientArea().height);
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IContentProposalProvider#getProposals(java.lang.String, int)
+     */
+    @Override
+    public final IContentProposal[] getProposals(final String contents,
+                                                 final int position) {
+        if (this.combo.getListVisible()) {
+            return new IContentProposal[0];
+        }
+
+        final List<String> matches = proposalsFor(this.pattern);
+
+        if (matches.isEmpty()) {
+            return new IContentProposal[0];
+        }
+
+        final IContentProposal[] proposals = new IContentProposal[matches.size()];
+        int i = 0;
+
+        for (final String match : matches) {
+            proposals[i++] = new ContentProposal(match);
+        }
+
+        return proposals;
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter2#getSelection(org.eclipse.swt.widgets.Control)
+     */
+    @Override
+    public final Point getSelection(final Control control) {
+        return this.combo.getSelection();
+    }
+
+    final void handleKeyPressed(final KeyEvent e) {
+        this.t2 = System.currentTimeMillis();
+
+        if ((this.t2 - this.t1) > this.duration) {
+            this.pattern = StringUtilities.EMPTY_STRING;
+        }
+
+        this.t1 = this.t2;
+
+        if (!Character.isLetter(e.character)) {
+            this.pattern = StringUtilities.EMPTY_STRING;
+        } else {
+            this.pattern += e.character;
+        }
+    }
+
+    /**
+     * Initializes the proposal provider. Must be called after construction.
+     */
+    final void init() {
+        final ContentProposalAdapter proposalAdapter = new ContentProposalAdapter(this.combo, this, this, null,
+                                                                                  getActivationChars());
+        proposalAdapter.setProposalAcceptanceStyle(ContentProposalAdapter.PROPOSAL_REPLACE);
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#insertControlContents(org.eclipse.swt.widgets.Control, java.lang.String, int)
+     */
+    @Override
+    public final void insertControlContents(final Control control,
+                                            final String text,
+                                            final int cursorPosition) {
+        final String contents = this.combo.getText();
+        final Point selection = this.combo.getSelection();
+
+        final StringBuilder builder = new StringBuilder();
+        builder.append(contents.substring(0, selection.x)).append(text);
+
+        if (selection.y < contents.length()) {
+            builder.append(contents.substring(selection.y, contents.length()));
+        }
+
+        setText(builder.toString());
+        //
+        //        selection.x = (selection.x + cursorPosition);
+        //        selection.y = selection.x;
+        //        this.combo.setSelection(selection);
+    }
+
+    /**
+     * @param pattern the pattern to use (can be <code>null</code> or empty)
+     * @return the proposals that match (never <code>null</code> but can be empty)
+     */
+    protected abstract List<String> proposalsFor(final String pattern);
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#setControlContents(org.eclipse.swt.widgets.Control, java.lang.String, int)
+     */
+    @Override
+    public final void setControlContents(final Control control,
+                                         final String contents,
+                                         final int cursorPosition) {
+        setText(contents);
+        setCursorPosition(control, cursorPosition);
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter#setCursorPosition(org.eclipse.swt.widgets.Control, int)
+     */
+    @Override
+    public final void setCursorPosition(final Control control,
+                                        final int index) {
+        this.combo.setSelection(new Point(index, index));
+    }
+
+    /**
+     * @see org.eclipse.jface.fieldassist.IControlContentAdapter2#setSelection(org.eclipse.swt.widgets.Control, org.eclipse.swt.graphics.Point)
+     */
+    @Override
+    public final void setSelection(final Control control,
+                                   final Point range) {
+        this.combo.setSelection(range);
+    }
+
+    private void setText(final String newSelection) {
+        final int index = this.combo.indexOf(newSelection);
+
+        if (index != -1) {
+            this.combo.select(index);
+        }
+    }
+}