Java tutorial
/******************************************************************************* * Copyright (c) 2009 Fraunhofer IWU 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: * Fraunhofer IWU - initial API and implementation *******************************************************************************/ package net.enilink.commons.ui.editor; import java.util.HashMap; import java.util.Map; import org.eclipse.jface.viewers.ISelection; import org.eclipse.jface.viewers.ISelectionChangedListener; import org.eclipse.jface.viewers.IStructuredSelection; import org.eclipse.jface.viewers.SelectionChangedEvent; import org.eclipse.jface.viewers.StructuredSelection; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.BusyIndicator; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.ui.forms.widgets.ScrolledPageBook; /** * This managed form part handles the 'details' portion of the 'master/details' * block. It has a page book that manages pages of details registered for the * current selection. * <p> * By default, details part accepts any number of pages. If dynamic page * provider is registered, this number may be excessive. To avoid running out of * steam (by creating a large number of pages with widgets on each), maximum * number of pages can be set to some reasonable value (e.g. 10). When this * number is reached, old pages (those created first) will be removed and * disposed as new ones are added. If the disposed pages are needed again after * that, they will be created again. */ public class EditorPartBook extends AbstractEditorPart implements ISelectionChangedListener { private Composite pageBook; private IStructuredSelection lastSelection, currentSelection; private Map<Object, PartBag> parts; private IEditorPartProvider partProvider; private int partLimit = Integer.MAX_VALUE; private boolean commitIfDirty; private int style = SWT.NONE; private static class PartBag { private static int counter; private int ticket; private IEditorPart part; private boolean fixed; public PartBag(IEditorPart part, boolean fixed) { this.part = part; this.fixed = fixed; this.ticket = ++counter; } public int getTicket() { return ticket; } public IEditorPart getPart() { return part; } public void dispose() { part.dispose(); part = null; } public boolean isDisposed() { return part == null; } public boolean isFixed() { return fixed; } public static int getCurrentTicket() { return counter; } } /** * Creates a details part by wrapping the provided page book. * * @param mform * the parent form * @param scrolledPageBook * the page book to wrap */ public EditorPartBook(boolean commitIfDirty) { this(commitIfDirty, SWT.V_SCROLL | SWT.H_SCROLL); } public EditorPartBook(boolean commitIfDirty, int style) { this.commitIfDirty = commitIfDirty; this.style = style; parts = new HashMap<Object, PartBag>(); } /** * Registers the details part to be used for all the objects of the provided * object class. * * @param objectClass * an object of type 'java.lang.Class' to be used as a key for * the provided page * @param page * the page to show for objects of the provided object class */ public void registerPart(Class<?> objectClass, IEditorPart page) { registerPart(objectClass, page, true); } private void registerPart(Object objectClass, IEditorPart page, boolean fixed) { parts.put(objectClass, new PartBag(page, fixed)); page.initialize(getForm()); } /** * Sets the dynamic page provider. The dynamic provider can return different * pages for objects of the same class based on their state. * * @param provider * the provider to use */ public void setPartProvider(IEditorPartProvider provider) { this.partProvider = provider; } /** * Commits the part by committing the current page. * * @param onSave * <code>true</code> if commit is requested as a result of the * 'save' action, <code>false</code> otherwise. */ public void commit(boolean onSave) { IEditorPart page = getCurrentPart(); if (page != null) { commitPart(currentSelection, page, false); } } /** * Returns the current page visible in the part. * * @return the current page */ public IEditorPart getCurrentPart() { Control control = pageBook instanceof ScrolledPageBook ? ((ScrolledPageBook) pageBook).getCurrentPage() : ((PageBook) pageBook).getCurrentPage(); if (control != null) { Object data = control.getData(); if (data instanceof IEditorPart) return (IEditorPart) data; } return null; } /* * (non-Javadoc) * * @see org.eclipse.ui.forms.IFormPart#dispose() */ public void dispose() { for (PartBag pageBag : parts.values()) { pageBag.dispose(); } } /** * Tests if the currently visible page is dirty. * * @return <code>true</code> if the page is dirty, <code>false</code> * otherwise. */ public boolean isDirty() { IEditorPart page = getCurrentPart(); if (page != null) { return page.isDirty(); } return false; } /** * Tests if the currently visible page is stale and needs refreshing. * * @return <code>true</code> if the page is stale, <code>false</code> * otherwise. */ public boolean isStale() { IEditorPart page = getCurrentPart(); if (page != null) { return page.isStale(); } return false; } /** * Refreshes the current page. */ public void refresh() { IEditorPart page = getCurrentPart(); if (page != null) { page.refresh(); } } /** * Sets the focus to the currently visible page. */ public boolean setFocus() { IEditorPart page = getCurrentPart(); if (page != null) { page.setFocus(); return true; } return false; } public Control getControl() { return pageBook; } public boolean setEditorInput(Object input) { return false; } public void selectionChanged(SelectionChangedEvent event) { lastSelection = currentSelection; selectionChanged(event.getSelection()); } public void selectionChanged(ISelection selection) { if (selection instanceof IStructuredSelection) { currentSelection = (IStructuredSelection) selection; } else { currentSelection = null; } update(); } private void update() { Object key = null; if (currentSelection != null && !currentSelection.isEmpty()) { Object firstElement = currentSelection.getFirstElement(); if (firstElement != null) { key = getKey(firstElement); } } showPart(key); } private Object getKey(Object object) { if (partProvider != null) { Object key = partProvider.getPartKey(object); if (key != null) { return key; } } return object.getClass(); } private void showPart(final Object key) { checkLimit(); final IEditorPart oldPart = getCurrentPart(); if (key != null) { PartBag pageBag = (PartBag) parts.get(key); IEditorPart part = pageBag != null ? pageBag.getPart() : null; if (part == null) { // try to get the page dynamically from the provider if (partProvider != null) { part = partProvider.getPart(key); if (part != null) { registerPart(key, part, false); } } } if (part != null) { final IEditorPart fpart = part; BusyIndicator.showWhile(pageBook.getDisplay(), new Runnable() { public void run() { if (!hasPage(key)) { Composite parent = createPage(key); fpart.createContents(parent); parent.setData(fpart); } // commit the current part if (commitIfDirty && oldPart != null && oldPart.isDirty()) { commitPart(lastSelection, oldPart, false); } fpart.setInput(currentSelection.getFirstElement()); if (oldPart != null) { oldPart.deactivate(); } fpart.activate(); // refresh the new part refreshPart(fpart); showPage(key); } }); return; } } // If we are switching from an old page to nothing, // don't loose data if (commitIfDirty && oldPart != null && oldPart.isDirty()) { commitPart(lastSelection, oldPart, false); } if (oldPart != null) { oldPart.deactivate(); } showEmptyPage(); } private Composite createPage(Object key) { if (pageBook instanceof ScrolledPageBook) { return ((ScrolledPageBook) pageBook).createPage(key); } return ((PageBook) pageBook).createPage(key); } private boolean hasPage(Object key) { if (pageBook instanceof ScrolledPageBook) { return ((ScrolledPageBook) pageBook).hasPage(key); } return ((PageBook) pageBook).hasPage(key); } private void showEmptyPage() { if (pageBook instanceof ScrolledPageBook) { ((ScrolledPageBook) pageBook).showEmptyPage(); } else { ((PageBook) pageBook).showEmptyPage(); } } private void showPage(Object key) { if (pageBook instanceof ScrolledPageBook) { ((ScrolledPageBook) pageBook).showPage(key); } else { ((PageBook) pageBook).showPage(key); } } private void removePage(Object key, boolean showEmptyPage) { if (pageBook instanceof ScrolledPageBook) { ((ScrolledPageBook) pageBook).removePage(key, showEmptyPage); } else { ((PageBook) pageBook).removePage(key, showEmptyPage); } } protected void refreshPart(IEditorPart detailsPart) { detailsPart.refresh(); } protected void commitPart(ISelection selection, IEditorPart detailsPart, boolean onSave) { detailsPart.commit(onSave); } private void checkLimit() { if (parts.size() <= getPartLimit()) return; // overflow int currentTicket = PartBag.getCurrentTicket(); int cutoffTicket = currentTicket - getPartLimit(); for (Map.Entry<Object, PartBag> entry : parts.entrySet()) { Object key = entry.getKey(); PartBag pageBag = entry.getValue(); if (pageBag.getTicket() <= cutoffTicket) { // candidate - see if it is active and not fixed if (!pageBag.isFixed() && !pageBag.getPart().equals(getCurrentPart())) { // drop it pageBag.dispose(); parts.remove(key); removePage(key, false); } } } } /** * Returns the maximum number of pages that should be maintained in this * part. When an attempt is made to add more pages, old pages are removed * and disposed based on the order of creation (the oldest pages are * removed). The exception is made for the page that should otherwise be * disposed but is currently active. * * @return maximum number of pages for this part */ public int getPartLimit() { return partLimit; } /** * Sets the page limit for this part. * * @see #getPartLimit() * @param partLimit * the maximum number of pages that should be maintained in this * part. */ public void setPartLimit(int partLimit) { this.partLimit = partLimit; checkLimit(); } @Override public void createContents(Composite parent) { if ((style & (SWT.V_SCROLL | SWT.H_SCROLL)) != 0) { this.pageBook = getWidgetFactory().createScrolledPageBook(parent, style); } else { this.pageBook = getWidgetFactory().createPageBook(parent, style); } } @Override public void setInput(Object input) { if (input != null) { selectionChanged(new StructuredSelection(input)); } else { selectionChanged(StructuredSelection.EMPTY); } } }