Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 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.wizard; import org.eclipse.jface.dialogs.DialogPage; import org.eclipse.jface.dialogs.IDialogSettings; import org.eclipse.jface.resource.ImageDescriptor; import org.eclipse.core.runtime.Assert; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.widgets.Shell; /** * An abstract base implementation of a wizard page. * <p> * Subclasses must implement the <code>createControl</code> method * to create the specific controls for the wizard page. * </p> * <p> * Subclasses may call the following methods to configure the wizard page: * <ul> * <li><code>setDescription</code></li> * <li><code>setErrorMessage</code></li> * <li><code>setImageDescriptor</code></li> * <li><code>setMessage</code></li> * <li><code>setPageComplete</code></li> * <li><code>setPreviousPage</code></li> * <li><code>setTitle</code></li> * </ul> * </p> * <p> * Subclasses may override these methods if required: * <ul> * <li><code>performHelp</code> - may be reimplemented to display help for the page</li> * <li><code>canFlipToNextPage</code> - may be extended or reimplemented</li> * <li><code>isPageComplete</code> - may be extended </li> * <li><code>setDescription</code> - may be extended </li> * <li><code>setTitle</code> - may be extended </li> * <li><code>dispose</code> - may be extended to dispose additional allocated SWT resources</li> * </ul> * </p> * <p> * Note that clients are free to implement <code>IWizardPage</code> from scratch * instead of subclassing <code>WizardPage</code>. Correct implementations of * <code>IWizardPage</code> will work with any correct implementation of * <code>IWizard</code>. * </p> */ public abstract class WizardPage extends DialogPage implements IWizardPage { /** * This page's name. */ private String name; /** * The wizard to which this page belongs; <code>null</code> * if this page has yet to be added to a wizard. */ private IWizard wizard = null; /** * Indicates whether this page is complete. */ private boolean isPageComplete = true; /** * The page that was shown right before this page became visible; * <code>null</code> if none. */ private IWizardPage previousPage = null; /** * Creates a new wizard page with the given name, and * with no title or image. * * @param pageName the name of the page */ protected WizardPage(String pageName) { this(pageName, null, (ImageDescriptor) null); } /** * Creates a new wizard page with the given name, title, and image. * * @param pageName the name of the page * @param title the title for this wizard page, * or <code>null</code> if none * @param titleImage the image descriptor for the title of this wizard page, * or <code>null</code> if none */ protected WizardPage(String pageName, String title, ImageDescriptor titleImage) { super(title, titleImage); Assert.isNotNull(pageName); // page name must not be null name = pageName; } /** * The <code>WizardPage</code> implementation of this <code>IWizardPage</code> * method returns <code>true</code> if this page is complete (<code>isPageComplete</code>) * and there is a next page to flip to. Subclasses may override (extend or reimplement). * * @see #getNextPage * @see #isPageComplete() */ @Override public boolean canFlipToNextPage() { return isPageComplete() && getNextPage() != null; } /** * Returns the wizard container for this wizard page. * * @return the wizard container, or <code>null</code> if this * wizard page has yet to be added to a wizard, or the * wizard has yet to be added to a container */ protected IWizardContainer getContainer() { if (wizard == null) { return null; } return wizard.getContainer(); } /** * Returns the dialog settings for this wizard page. * * @return the dialog settings, or <code>null</code> if none */ protected IDialogSettings getDialogSettings() { if (wizard == null) { return null; } return wizard.getDialogSettings(); } @Override public Image getImage() { Image result = super.getImage(); if (result == null && wizard != null) { return wizard.getDefaultPageImage(); } return result; } @Override public String getName() { return name; } @Override public IWizardPage getNextPage() { if (wizard == null) { return null; } return wizard.getNextPage(this); } @Override public IWizardPage getPreviousPage() { if (previousPage != null) { return previousPage; } if (wizard == null) { return null; } return wizard.getPreviousPage(this); } /** * The <code>WizardPage</code> implementation of this method declared on * <code>DialogPage</code> returns the shell of the container. * The advantage of this implementation is that the shell is accessable * once the container is created even though this page's control may not * yet be created. */ @Override public Shell getShell() { IWizardContainer container = getContainer(); if (container == null) { return null; } // Ask the wizard since our contents may not have been created. return container.getShell(); } @Override public IWizard getWizard() { return wizard; } /** * Returns whether this page is the current one in the wizard's container. * * @return <code>true</code> if the page is active, * and <code>false</code> otherwise */ protected boolean isCurrentPage() { return (getContainer() != null && this == getContainer().getCurrentPage()); } /** * The <code>WizardPage</code> implementation of this <code>IWizard</code> method * returns the value of an internal state variable set by * <code>setPageComplete</code>. Subclasses may extend. */ @Override public boolean isPageComplete() { return isPageComplete; } /** * The <code>WizardPage</code> implementation of this <code>IDialogPage</code> * method extends the <code>DialogPage</code> implementation to update * the wizard container title bar. Subclasses may extend. */ @Override public void setDescription(String description) { super.setDescription(description); if (isCurrentPage()) { getContainer().updateTitleBar(); } } /** * The <code>WizardPage</code> implementation of this method * declared on <code>DialogPage</code> updates the container * if this is the current page. */ @Override public void setErrorMessage(String newMessage) { super.setErrorMessage(newMessage); if (isCurrentPage()) { getContainer().updateMessage(); } } /** * The <code>WizardPage</code> implementation of this method * declared on <code>DialogPage</code> updates the container * if this page is the current page. */ @Override public void setImageDescriptor(ImageDescriptor image) { super.setImageDescriptor(image); if (isCurrentPage()) { getContainer().updateTitleBar(); } } /** * The <code>WizardPage</code> implementation of this method * declared on <code>DialogPage</code> updates the container * if this is the current page. */ @Override public void setMessage(String newMessage, int newType) { super.setMessage(newMessage, newType); if (isCurrentPage()) { getContainer().updateMessage(); } } /** * Sets whether this page is complete. * <p> * This information is typically used by the wizard to decide * when it is okay to move on to the next page or finish up. * </p> * * @param complete <code>true</code> if this page is complete, and * and <code>false</code> otherwise * @see #isPageComplete() */ public void setPageComplete(boolean complete) { isPageComplete = complete; if (isCurrentPage()) { getContainer().updateButtons(); } } @Override public void setPreviousPage(IWizardPage page) { previousPage = page; } /** * The <code>WizardPage</code> implementation of this <code>IDialogPage</code> * method extends the <code>DialogPage</code> implementation to update * the wizard container title bar. Subclasses may extend. */ @Override public void setTitle(String title) { super.setTitle(title); if (isCurrentPage()) { getContainer().updateTitleBar(); } } @Override public void setWizard(IWizard newWizard) { wizard = newWizard; } /** * Returns a printable representation of this wizard page suitable * only for debug purposes. */ @Override public String toString() { return name; } }