r/org.eclipse.statet.r.debug.core/src/org/eclipse/statet/internal/r/debug/core/model/RElementVariableValue.java

/*=============================================================================#
 # Copyright (c) 2010, 2019 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.internal.r.debug.core.model;

import java.util.concurrent.atomic.AtomicReference;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;
import org.eclipse.statet.jcommons.status.ProgressMonitor;
import org.eclipse.statet.jcommons.status.Status;
import org.eclipse.statet.jcommons.status.StatusException;
import org.eclipse.statet.jcommons.status.Statuses;

import org.eclipse.statet.r.core.data.CombinedRElement;
import org.eclipse.statet.r.debug.core.IRVariable;
import org.eclipse.statet.rj.data.RObject;
import org.eclipse.statet.rj.data.UnexpectedRDataException;
import org.eclipse.statet.rj.services.FQRObjectRef;
import org.eclipse.statet.rj.services.util.dataaccess.LazyRStore;
import org.eclipse.statet.rj.services.util.dataaccess.LazyRStore.Fragment;
import org.eclipse.statet.rj.services.util.dataaccess.RDataAssignment;
import org.eclipse.statet.rj.ts.core.RToolService;


@NonNullByDefault
public class RElementVariableValue<TRElement extends CombinedRElement> extends RElementValue<TRElement> {
	
	
	protected abstract class RDataLoader<V extends RObject> implements LazyRStore.Updater<V> {
		
		
		private @Nullable FQRObjectRef ref;
		
		
		public RDataLoader() {
		}
		
		
		@Override
		public void scheduleUpdate(final LazyRStore<V> store,
				final @Nullable RDataAssignment assignment, final @Nullable Fragment<V> fragment,
				final int flags, final ProgressMonitor m) {
			final AtomicReference<Status> set= new AtomicReference<>();
			V data= null;
			try {
				final RMainThread thread= RElementVariableValue.this.variable.getThread();
				data= thread.loadData(thread.new AccessDataRunnable<V>() {
					@Override
					protected int getRequiredStamp() {
						return RElementVariableValue.this.stamp;
					}
					private @Nullable FQRObjectRef getRef(final ProgressMonitor m) {
						if (RDataLoader.this.ref == null) {
							RDataLoader.this.ref= getThread().createElementRef(
									RElementVariableValue.this.element, getRequiredStamp(),
									m );
						}
						return RDataLoader.this.ref;
					}
					@Override
					protected V doRun(final RToolService r, final ProgressMonitor m)
							throws StatusException, UnexpectedRDataException {
						final FQRObjectRef ref= getRef(m);
						if (ref == null) {
							return null;
						}
						if (assignment != null) {
							RDataLoader.this.doSet(ref, assignment, r, m);
							set.set(Statuses.OK_STATUS);
						}
						if (fragment != null) {
							return RDataLoader.this.doLoad(ref,
									fragment, r, m);
						}
						else {
							return null;
						}
					}
				});
			}
			finally {
				if (assignment != null) {
					store.updateAssignment(assignment, set.get());
				}
				if (fragment != null) {
					store.updateFragment(fragment, data);
				}
			}
		}
		
		protected void doSet(final FQRObjectRef ref,
				final RDataAssignment assignment,
				final RToolService r, final ProgressMonitor m) throws StatusException, UnexpectedRDataException {
			throw new UnsupportedOperationException();
		}
		
		protected abstract V doLoad(FQRObjectRef ref,
				Fragment<V> fragment,
				RToolService r, ProgressMonitor m) throws StatusException, UnexpectedRDataException;
		
	}
	
	
	protected final RElementVariable variable;
	
	
	public RElementVariableValue(final RElementVariable variable) {
		super(variable.getDebugTarget(),
				(TRElement) variable.getCurrentElement(), variable.getCurrentStamp());
		this.variable= variable;
	}
	
	
	@Override
	public IRVariable getAssignedVariable() {
		return this.variable;
	}
	
}