contentproposaladapter.java

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/*******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.fieldassist;

import java.util.ArrayList;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.bindings.keys.KeyStroke;
import org.eclipse.jface.dialogs.PopupDialog;
import org.eclipse.jface.util.Assert;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.FocusAdapter;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.Text;

/**
 * ContentProposalAdapter can be used to attach content proposal behavior to a
 * control. This behavior includes obtaining proposals, opening a popup dialog,
 * managing the content of the control relative to the selections in the popup,
 * and optionally opening up a secondary popup to further describe proposals.
 * <p>
 * A number of configurable options are provided to determine how the control
 * content is altered when a proposal is chosen, how the content proposal popup
 * is activated, and whether any filtering should be done on the proposals as
 * the user types characters.
 * <p>
 * This class is not intended to be subclassed.
 * 
 * @since 3.2
 */
public class ContentProposalAdapter {

	/*
	 * The lightweight popup used to show content proposals for a text field. If
	 * additional information exists for a proposal, then selecting that
	 * proposal will result in the information being displayed in a secondary
	 * popup.
	 */
	class ContentProposalPopup extends PopupDialog {
		/*
		 * The listener we install on the popup and related controls to
		 * determine when to close the popup. Some events (move, resize, close,
		 * deactivate) trigger closure as soon as they are received, simply
		 * because one of the registered listeners received them. Other events
		 * depend on additional circumstances.
		 */
		private final class PopupCloserListener implements Listener {
			private boolean scrollbarClicked = false;

			public void handleEvent(final Event e) {

				// If focus is leaving an important widget or the field's
				// shell is deactivating
				if (e.type == SWT.FocusOut) {
					scrollbarClicked = false;
					/*
					 * Ignore this event if it's only happening because focus is
					 * moving between the popup shells, their controls, or a
					 * scrollbar. Do this in an async since the focus is not
					 * actually switched when this event is received.
					 */
					e.display.asyncExec(new Runnable() {
						public void run() {
							if (isValid()) {
								if (scrollbarClicked
										|| hasFocus()
										|| (infoPopup != null && infoPopup
												.hasFocus())) {
									return;
								}
								// Workaround a problem on X and Mac, whereby at
								// this point, the focus control is not known.
								// This can happen, for example, when resizing
								// the popup shell on the Mac.
								// Check the active shell.
								Shell activeShell = e.display.getActiveShell();
								if (activeShell == getShell()
										|| (infoPopup != null && infoPopup
												.getShell() == activeShell)) {
									return;
								}
								/*
								 * System.out.println(e);
								 * System.out.println(e.display.getFocusControl());
								 * System.out.println(e.display.getActiveShell());
								 */
								close();
							}
						}
					});
					return;
				}

				// Scroll bar has been clicked. Remember this for focus event
				// processing.
				if (e.type == SWT.Selection) {
					scrollbarClicked = true;
					return;
				}
				// For all other events, merely getting them dictates closure.
				close();
			}

			// Install the listeners for events that need to be monitored for
			// popup closure.
			void installListeners() {
				// Listeners on this popup's table and scroll bar
				proposalTable.addListener(SWT.FocusOut, this);
				ScrollBar scrollbar = proposalTable.getVerticalBar();
				if (scrollbar != null) {
					scrollbar.addListener(SWT.Selection, this);
				}

				// Listeners on this popup's shell
				getShell().addListener(SWT.Deactivate, this);
				getShell().addListener(SWT.Close, this);

				// Listeners on the target control
				control.addListener(SWT.MouseDoubleClick, this);
				control.addListener(SWT.MouseDown, this);
				control.addListener(SWT.Dispose, this);
				control.addListener(SWT.FocusOut, this);
				// Listeners on the target control's shell
				Shell controlShell = control.getShell();
				controlShell.addListener(SWT.Move, this);
				controlShell.addListener(SWT.Resize, this);

			}

			// Remove installed listeners
			void removeListeners() {
				if (isValid()) {
					proposalTable.removeListener(SWT.FocusOut, this);
					ScrollBar scrollbar = proposalTable.getVerticalBar();
					if (scrollbar != null) {
						scrollbar.removeListener(SWT.Selection, this);
					}

					getShell().removeListener(SWT.Deactivate, this);
					getShell().removeListener(SWT.Close, this);
				}

				if (control != null && !control.isDisposed()) {

					control.removeListener(SWT.MouseDoubleClick, this);
					control.removeListener(SWT.MouseDown, this);
					control.removeListener(SWT.Dispose, this);
					control.removeListener(SWT.FocusOut, this);

					Shell controlShell = control.getShell();
					controlShell.removeListener(SWT.Move, this);
					controlShell.removeListener(SWT.Resize, this);
				}
			}
		}

		/*
		 * The listener we will install on the target control.
		 */
		private final class TargetControlListener implements Listener {
			// Key events from the control
			public void handleEvent(Event e) {
				if (!isValid()) {
					return;
				}

				char key = e.character;

				// Traverse events are handled depending on whether the
				// event has a character.
				if (e.type == SWT.Traverse) {
					// If the traverse event contains a legitimate character,
					// then we must set doit false so that the widget will
					// receive the key event. We return immediately so that
					// the character is handled only in the key event.
					// See https://bugs.eclipse.org/bugs/show_bug.cgi?id=132101
					if (key != 0) {
						e.doit = false;
						return;
					}
					// Traversal does not contain a character. Set doit true
					// to indicate TRAVERSE_NONE will occur and that no key
					// event will be triggered. We will check for navigation 
					// keys below.
					e.detail = SWT.TRAVERSE_NONE;
					e.doit = true;
				} else {
					// Default is to only propagate when configured that way.
					// Some keys will always set doit to false anyway.
					e.doit = propagateKeys;
				}

				// No character. Check for navigation keys. 

				if (key == 0) {
					int newSelection = proposalTable.getSelectionIndex();
					int visibleRows = (proposalTable.getSize().y / proposalTable
							.getItemHeight()) - 1;
					switch (e.keyCode) {
					case SWT.ARROW_UP:
						newSelection -= 1;
						if (newSelection < 0) {
							newSelection = proposalTable.getItemCount() - 1;
						}
						// Not typical - usually we get this as a Traverse and
						// therefore it never propagates.  Added for consistency.
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}

						break;

					case SWT.ARROW_DOWN:
						newSelection += 1;
						if (newSelection > proposalTable.getItemCount() - 1) {
							newSelection = 0;
						}
						// Not typical - usually we get this as a Traverse and
						// therefore it never propagates.  Added for consistency.
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}

						break;

					case SWT.PAGE_DOWN:
						newSelection += visibleRows;
						if (newSelection >= proposalTable.getItemCount()) {
							newSelection = proposalTable.getItemCount() - 1;
						}
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}
						break;

					case SWT.PAGE_UP:
						newSelection -= visibleRows;
						if (newSelection < 0) {
							newSelection = 0;
						}
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}
						break;

					case SWT.HOME:
						newSelection = 0;
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}
						break;

					case SWT.END:
						newSelection = proposalTable.getItemCount() - 1;
						if (e.type == SWT.KeyDown) {
							// don't propagate to control
							e.doit = false;		
						}
						break;
						
					// If received as a Traverse, these should propagate 
				    // to the control as keydown.  If received as a keydown,
				    // proposals should be recomputed since the cursor
				    // position has changed.
					case SWT.ARROW_LEFT:
					case SWT.ARROW_RIGHT:
						if (e.type == SWT.Traverse) {
							e.doit = false;
						} else {
							e.doit = true;
							String contents = getControlContentAdapter().getControlContents(
									getControl());
							// If there are no contents, changes in cursor position 
							// have no effect.  Note also that we do not affect the filter
							// text on ARROW_LEFT as we would with BS.
							if (contents.length() > 0) {
								asyncRecomputeProposals(filterText);
							}
						}
						break;

					// Any unknown keycodes will cause the popup to close.
					// Modifier keys are explicitly checked and ignored because
					// they are not complete yet (no character).
					default:
						if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1
								&& e.keyCode != SWT.MOD2
								&& e.keyCode != SWT.MOD3
								&& e.keyCode != SWT.MOD4) {
							close();
						}
						return;
					}

					// If any of these navigation events caused a new selection,
					// then handle that now and return.
					if (newSelection >= 0) {
						selectProposal(newSelection);
					}
					return;
				}

				// key != 0
				// Check for special keys involved in cancelling, accepting, or
				// filtering the proposals.
				switch (key) {
				case SWT.ESC:
					e.doit = false;
					close();
					break;

				case SWT.LF:
				case SWT.CR:
					e.doit = false;
					Object p = getSelectedProposal();
					if (p != null) {
						acceptCurrentProposal();
					}
					close();
					break;

				case SWT.TAB:
					e.doit = false;
					getShell().setFocus();
					return;

				case SWT.BS:
					// Backspace should back out of any stored filter text
					if (filterStyle != FILTER_NONE) {
						// We have no filter to back out of, so do nothing
						if (filterText.length() == 0) {
							return;
						}
						// There is filter to back out of
						filterText = filterText.substring(0, filterText
								.length() - 1);
						asyncRecomputeProposals(filterText);
						return;
					}
					// There is no filtering provided by us, but some 
					// clients provide their own filtering based on content.
					// Recompute the proposals if the cursor position
					// will change (is not at 0).  
					int pos = getControlContentAdapter().getCursorPosition(getControl());
					// We rely on the fact that the contents and pos do not yet
					// reflect the result of the BS.  If the contents were already empty, then BS should not cause
					// a recompute.
					if (pos > 0) {
						asyncRecomputeProposals(filterText);
					}
					break;

				default:
					// If the key is a defined unicode character, and not one of
					// the special cases processed above, update the filter text
					// and filter the proposals.
					if (Character.isDefined(key)) {
						if (filterStyle == FILTER_CUMULATIVE) {
							filterText = filterText + String.valueOf(key);
						} else if (filterStyle == FILTER_CHARACTER) {
							filterText = String.valueOf(key);
						}
						// Recompute proposals after processing this event.
						asyncRecomputeProposals(filterText);
					}
					break;
				}
			}
		}

		/*
		 * Internal class used to implement the secondary popup.
		 */
		private class InfoPopupDialog extends PopupDialog {

			/*
			 * The text control that displays the text.
			 */
			private Text text;

			/*
			 * The String shown in the popup.
			 */
			private String contents = EMPTY;

			/*
			 * Construct an info-popup with the specified parent.
			 */
			InfoPopupDialog(Shell parent) {
				super(parent, PopupDialog.HOVER_SHELLSTYLE, false, false,
						false, false, null, null);
			}

			/*
			 * Create a text control for showing the info about a proposal.
			 */
			protected Control createDialogArea(Composite parent) {
				text = new Text(parent, SWT.MULTI | SWT.READ_ONLY | SWT.WRAP
						| SWT.NO_FOCUS);

				// Use the compact margins employed by PopupDialog.
				GridData gd = new GridData(GridData.BEGINNING
						| GridData.FILL_BOTH);
				gd.horizontalIndent = PopupDialog.POPUP_HORIZONTALSPACING;
				gd.verticalIndent = PopupDialog.POPUP_VERTICALSPACING;
				text.setLayoutData(gd);
				text.setText(contents);

				// since SWT.NO_FOCUS is only a hint...
				text.addFocusListener(new FocusAdapter() {
					public void focusGained(FocusEvent event) {
						ContentProposalPopup.this.close();
					}
				});
				return text;
			}

			/*
			 * Adjust the bounds so that we appear adjacent to our parent shell
			 */
			protected void adjustBounds() {
				Rectangle parentBounds = getParentShell().getBounds();
				Rectangle proposedBounds;
				// Try placing the info popup to the right
				Rectangle rightProposedBounds = new Rectangle(parentBounds.x
						+ parentBounds.width
						+ PopupDialog.POPUP_HORIZONTALSPACING, parentBounds.y
						+ PopupDialog.POPUP_VERTICALSPACING,
						parentBounds.width, parentBounds.height);