/*******************************************************************************
* Copyright (c) 2005, 2011 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.debug.internal.ui.viewers.provisional;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.ISchedulingRule;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.debug.internal.ui.viewers.AsynchronousSchedulingRuleFactory;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
/**
* Abstract implementation of an asynchronous content adapter.
* <p>
* Clients may subclass this class.
* </p>
* @since 3.2
*/
public abstract class AsynchronousContentAdapter implements IAsynchronousContentAdapter {
protected static final Object[] EMPTY = new Object[0];
/*
* (non-Javadoc)
* @see org.eclipse.debug.internal.ui.viewers.provisional.IAsynchronousContentAdapter#retrieveChildren(java.lang.Object, org.eclipse.debug.internal.ui.viewers.provisional.IPresentationContext, org.eclipse.debug.internal.ui.viewers.provisional.IChildrenRequestMonitor)
*/
@Override
public void retrieveChildren(final Object parent, final IPresentationContext context, final IChildrenRequestMonitor result) {
Job job = new Job("Retrieving Children") { //$NON-NLS-1$
@Override
protected IStatus run(IProgressMonitor monitor) {
if (!monitor.isCanceled()) {
computeChildren(parent, context, result);
}
return Status.OK_STATUS;
}
};
job.setSystem(true);
job.setRule(getRetrieveChildrenRule(parent, context));
job.schedule();
}
/**
* Returns the scheduling rule for jobs retrieving children.
*
* @param parent the parent
* @param context the presentation context
* @return scheduling rule or <code>null</code>
*/
protected ISchedulingRule getRetrieveChildrenRule(Object parent, IPresentationContext context) {
return AsynchronousSchedulingRuleFactory.getDefault().newSerialPerObjectRule(context);
}
/*
* (non-Javadoc)
* @see org.eclipse.debug.internal.ui.viewers.provisional.IAsynchronousContentAdapter#isContainer(java.lang.Object, org.eclipse.debug.internal.ui.viewers.provisional.IPresentationContext, org.eclipse.debug.internal.ui.viewers.provisional.IContainerRequestMonitor)
*/
@Override
public void isContainer(final Object element, final IPresentationContext context, final IContainerRequestMonitor result) {
Job job = new Job("Computing hasChildren") { //$NON-NLS-1$
@Override
protected IStatus run(IProgressMonitor monitor) {
if (!monitor.isCanceled()) {
computeIsContainer(element, context, result);
}
return Status.OK_STATUS;
}
};
job.setSystem(true);
job.setRule(getIsContainerRule(element, context));
job.schedule();
}
/**
* Returns the scheduling rule for jobs determining if an element is a container.
*
* @param parent the parent
* @param context the presentation context
* @return scheduling rule or <code>null</code>
*/
protected ISchedulingRule getIsContainerRule(Object parent, IPresentationContext context) {
return AsynchronousSchedulingRuleFactory.getDefault().newSerialPerObjectRule(context);
}
/**
* Computes the children for the given parent in the specified context.
*
* @param parent parent to retrieve children for
* @param context presentation context
* @param monitor result to report to
*/
protected void computeChildren(Object parent, IPresentationContext context, IChildrenRequestMonitor monitor) {
if (!monitor.isCanceled()) {
IStatus status = Status.OK_STATUS;
try {
if (supportsContext(context)) {
monitor.addChildren(getChildren(parent, context));
}
} catch (CoreException e) {
status = e.getStatus();
}
monitor.setStatus(status);
monitor.done();
}
}
/**
* Computes whether the given element is a container.
*
* @param parent potential parent
* @param context presentation context
* @param monitor result to report to
*/
protected void computeIsContainer(Object parent, IPresentationContext context, IContainerRequestMonitor monitor) {
if (!monitor.isCanceled()) {
IStatus status = Status.OK_STATUS;
try {
monitor.setIsContainer(hasChildren(parent, context));
} catch (CoreException e) {
status = e.getStatus();
}
monitor.setStatus(status);
monitor.done();
}
}
/**
* Returns the children for the given parent in the specified context.
*
* @param parent element to retrieve children for
* @param context context children will be presented in
* @return children
* @throws CoreException if an exception occurs retrieving children
*/
protected abstract Object[] getChildren(Object parent, IPresentationContext context) throws CoreException;
/**
* Returns whether the given element has children in the specified context.
*
* @param element element that may have children
* @param context context element will be presented in
* @return whether the given element has children in the specified context
* @throws CoreException if an exception occurs determining whether the
* element has children
*/
protected abstract boolean hasChildren(Object element, IPresentationContext context) throws CoreException;
/**
* Returns whether this adapter supports the given context.
*
* @param context the presentation context
* @return whether this adapter supports the given context
*/
protected boolean supportsContext(IPresentationContext context) {
return supportsPartId(context.getId());
}
/**
* Returns whether this adapter provides content in the specified part.
*
* @param id part id
* @return whether this adapter provides content in the specified part
*/
protected abstract boolean supportsPartId(String id);
}