| /******************************************************************************* |
| * Copyright (c) 2007, 2011 IBM Corporation 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: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.equinox.internal.p2.ui.model; |
| |
| import java.util.*; |
| import org.eclipse.core.runtime.IProgressMonitor; |
| import org.eclipse.core.runtime.NullProgressMonitor; |
| import org.eclipse.equinox.internal.p2.ui.ElementQueryDescriptor; |
| import org.eclipse.equinox.internal.p2.ui.QueryProvider; |
| import org.eclipse.equinox.internal.p2.ui.query.IUViewQueryContext; |
| import org.eclipse.equinox.p2.query.IQueryable; |
| import org.eclipse.equinox.p2.ui.Policy; |
| import org.eclipse.equinox.p2.ui.ProvisioningUI; |
| |
| /** |
| * Element class that represents an element that gets its children by using a |
| * query. |
| * |
| * @since 3.4 |
| * |
| */ |
| public abstract class QueriedElement extends ProvElement { |
| |
| protected IQueryable<?> queryable; |
| // This cache is used internally to facilitate child elements |
| // that want to eliminate duplicates from the parent hierarchy. |
| // This cache is *not* used as a general purpose child cache. |
| private Collection<?> cachedChildren; |
| private static final Object[] EMPTY = new Object[0]; |
| |
| protected QueriedElement(Object parent) { |
| super(parent); |
| } |
| |
| public Policy getPolicy() { |
| Object parent = getParent(this); |
| if (parent instanceof QueriedElement) |
| return ((QueriedElement) parent).getPolicy(); |
| return getProvisioningUI().getPolicy(); |
| } |
| |
| public ProvisioningUI getProvisioningUI() { |
| Object parent = getParent(this); |
| if (parent instanceof QueriedElement) |
| return ((QueriedElement) parent).getProvisioningUI(); |
| // if we really can't find a UI then get the default. In general this should |
| // not happen though. Turn on tracing in getDefaultUI() to see places where |
| // it is happening. |
| return ProvisioningUI.getDefaultUI(); |
| |
| } |
| |
| public IUViewQueryContext getQueryContext() { |
| Object parent = getParent(this); |
| if (parent instanceof QueriedElement) |
| return ((QueriedElement) parent).getQueryContext(); |
| return null; |
| } |
| |
| @Override |
| public Object[] getChildren(Object o) { |
| return fetchChildren(o, new NullProgressMonitor()); |
| } |
| |
| @Override |
| public String getLabel(Object o) { |
| return null; |
| } |
| |
| /** |
| * Return the query type that is appropriate for this element when there is no |
| * query context. |
| * |
| * @return The integer query type |
| */ |
| protected abstract int getDefaultQueryType(); |
| |
| /** |
| * Return the query type that should be used for this element. Depending on the |
| * element, the query type may take the query context into account. Subclasses |
| * should override this method if there are context-dependent decisions to be |
| * made to determine the query. |
| * |
| * @return The integer query type |
| */ |
| public int getQueryType() { |
| return getDefaultQueryType(); |
| } |
| |
| protected Object[] fetchChildren(Object o, IProgressMonitor monitor) { |
| cachedChildren = Collections.emptyList(); |
| QueryProvider provider = new QueryProvider(getProvisioningUI()); |
| ElementQueryDescriptor queryDescriptor = provider.getQueryDescriptor(this); |
| if (queryDescriptor == null) |
| return new Object[0]; |
| Collection<?> results = queryDescriptor.performQuery(monitor); |
| cachedChildren = Collections.unmodifiableCollection(results); |
| if (results.size() > 0) { |
| return getFilteredChildren(results); |
| } |
| return new Object[0]; |
| } |
| |
| protected Object[] getFilteredChildren(Collection<?> results) { |
| Collection<Object> returnedChildren = new HashSet<>(); |
| returnedChildren.addAll(results); |
| Object[] siblings = getSiblings(); |
| for (Object sibling : siblings) { |
| returnedChildren.remove(sibling); |
| } |
| return returnedChildren.toArray(); |
| } |
| |
| public void setQueryable(IQueryable<?> queryable) { |
| this.queryable = queryable; |
| } |
| |
| public IQueryable<?> getQueryable() { |
| return queryable; |
| } |
| |
| /** |
| * Return a boolean indicating whether the receiver has enough information to |
| * get its queryable. This is used in lieu of {{@link #getQueryable()} when lazy |
| * initialization of the queryable is not desired, and a client wishes to know |
| * whether the queryable could be obtained. Subclasses that cache information |
| * needed to retrieve the queryable rather than the queryable itself should |
| * override this. |
| * |
| * @return <code>true</code> if the receiver has enough information to retrieve |
| * its queryable, <code>false</code> if it does not. |
| */ |
| public boolean knowsQueryable() { |
| return queryable != null; |
| } |
| |
| /** |
| * Return a boolean indicating whether the receiver actually has its queryable. |
| * This is used in lieu of {{@link #getQueryable()} when lazy initialization of |
| * the queryable is not desired. For example, when working with an element whose |
| * queryable may be expensive to obtain, clients may check this before actually |
| * getting the queryable. Subclasses should typically not need to override this. |
| * |
| * @return <code>true</code> if the receiver has its queryable, |
| * <code>false</code> if it does not yet. |
| */ |
| public boolean hasQueryable() { |
| return queryable != null; |
| } |
| |
| public Object[] getCachedChildren() { |
| if (cachedChildren == null) |
| return EMPTY; |
| return cachedChildren.toArray(); |
| } |
| |
| protected Object[] getSiblings() { |
| Object parent = getParent(this); |
| if (parent instanceof QueriedElement) |
| return ((QueriedElement) parent).getCachedChildren(); |
| if (parent instanceof IUElementListRoot) |
| return ((IUElementListRoot) parent).getChildren(parent); |
| return new Object[0]; |
| } |
| } |