Java tutorial
/******************************************************************************* * Copyright (c) 2015-2019 vogella GmbH and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * Simon Scholz <simon.scholz@vogella.com> - Bug 446616 * Alexander Fedorov <alexander.fedorov@arsysop.ru> - Bug 460381 *******************************************************************************/ package org.eclipse.jface.dialogs; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.List; import java.util.Optional; import java.util.stream.Collectors; import org.eclipse.jface.viewers.ISelection; import org.eclipse.jface.viewers.IStructuredSelection; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Label; import org.eclipse.swt.widgets.Shell; /** * The abstract implementation of a selection dialog. It can be primed with * initial selections (<code>setInitialSelection</code>), and returns the final * selection (via <code>getResult</code>) after completion. * <p> * Clients may subclass this dialog to inherit its selection facilities. * </p> * * @param <T> * which declares the type of the elements in the * {@link AbstractSelectionDialog}. * @since 3.11 * */ public abstract class AbstractSelectionDialog<T> extends TrayDialog { // the final collection of selected elements private Collection<T> result; // a list of the initially-selected elements private List<T> initialSelection; // title of dialog private String title; // message to show user private String message = ""; //$NON-NLS-1$ // dialog bounds strategy private int dialogBoundsStrategy = Dialog.DIALOG_PERSISTLOCATION | Dialog.DIALOG_PERSISTSIZE; // dialog settings for storing bounds private IDialogSettings dialogBoundsSettings = null; /** * Creates a dialog instance. * * @param parentShell * the parent shell */ protected AbstractSelectionDialog(Shell parentShell) { super(parentShell); } @Override protected void configureShell(Shell shell) { super.configureShell(shell); if (title != null) { shell.setText(title); } } /** * Creates the message area for this dialog. * <p> * This method is provided to allow subclasses to decide where the message * will appear on the screen. * </p> * * @param composite * the parent composite * @return the message label */ protected Label createMessageArea(Composite composite) { Label label = new Label(composite, SWT.NONE); if (message != null) { label.setText(message); } label.setFont(composite.getFont()); return label; } /** * Returns the collection of initial element selections. * * @return Collection */ protected List<T> getInitialSelection() { if (null == initialSelection) { return Collections.emptyList(); } return Collections.unmodifiableList(initialSelection); } /** * Returns the message for this dialog. * * @return the message for this dialog */ protected String getMessage() { return message; } /** * Returns the collection of selections made by the user. * * @return the collection of selected elements, or * <code>Collections.emptyList()</code> if no result was set */ public Collection<T> getResult() { return result != null ? result : Collections.emptyList(); } /** * Returns an <code>java.util.Optional<T></code> containing the first * element from the collection of selections made by the user. Returns * {@link Optional#empty()} if no element has been selected. * * @return an <code>java.util.Optional<T></code> containing the first * result element if one exists. Otherwise {@link Optional#empty()} is * returned. * @since 3.16 */ public Optional<T> getFirstResult() { if (result != null) { return result.stream().findFirst(); } return Optional.empty(); } /** * Sets the initial selection in this selection dialog to the given * elements. * * @param selectedElements * the elements to select */ public void setInitialSelection(T... selectedElements) { initialSelection = Arrays.asList(selectedElements); } /** * Sets the initial selection in this selection dialog to the given * elements. * * @param selectedElements * the List of elements to select */ public void setInitialSelection(Collection<T> selectedElements) { initialSelection = new ArrayList<>(selectedElements); } /** * Sets the message for this dialog. * * @param message * the message */ public void setMessage(String message) { this.message = message; } /** * Set the selections made by the user. * <p> * The result may be accessed using <code>getResult</code>. * </p> * * @param newUserSelection collection of selected elements */ protected void setResult(Collection<T> newUserSelection) { result = newUserSelection; } /** * Set the selections made by the user. * <p> * The result may be accessed using <code>getResult</code>. * </p> * * @param newUserSelection - the new values */ protected void setResult(T... newUserSelection) { if (newUserSelection == null) { result = null; } else { result = Arrays.asList(newUserSelection); } } /** * Set the selections obtained from a viewer. * * @param selection selection obtained from a viewer * @param target target type to check for <code>instanceof</code> * @since 3.16 */ protected void setResult(ISelection selection, Class<T> target) { List<T> selected = null; if (selection instanceof IStructuredSelection && target != null) { IStructuredSelection structured = (IStructuredSelection) selection; selected = ((List<?>) structured.toList()).stream().filter(p -> target.isInstance(p)) .map(p -> target.cast(p)).collect(Collectors.toList()); } setResult(selected); } /** * Sets the title for this dialog. * * @param title * the title */ public void setTitle(String title) { this.title = title; } /** * Set the dialog settings that should be used to save the bounds of this * dialog. This method is provided so that clients that directly use * SelectionDialogs without subclassing them may specify how the bounds of * the dialog are to be saved. * * @param settings * the {@link IDialogSettings} that should be used to store the * bounds of the dialog * * @param strategy * the integer constant specifying how the bounds are saved. * Specified using {@link Dialog#DIALOG_PERSISTLOCATION} and * {@link Dialog#DIALOG_PERSISTSIZE}. * * @since 3.2 * * @see Dialog#getDialogBoundsStrategy() * @see Dialog#getDialogBoundsSettings() */ public void setDialogBoundsSettings(IDialogSettings settings, int strategy) { dialogBoundsStrategy = strategy; dialogBoundsSettings = settings; } @Override protected IDialogSettings getDialogBoundsSettings() { return dialogBoundsSettings; } @Override protected int getDialogBoundsStrategy() { return dialogBoundsStrategy; } @Override protected boolean isResizable() { return true; } }