/*
* Copyright 2003-2016 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.mps.generator.impl;
import jetbrains.mps.generator.ModelGenerationPlan.Checkpoint;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.mps.openapi.model.SModel;
import org.jetbrains.mps.openapi.model.SModelReference;
import java.util.ArrayList;
import java.util.List;
/**
* Trace transformation of active model as it transitions from one CP to another.
*
* ModelTransitions with TransitionTrace pair is somewhat similar to ModelCheckpoints with CheckpointState, the former tracking
* active transformation sequence, while latter representing recorded transformation sequence. Indeed, for the active transformation,
* there might me partially ready recorded one, and perhaps we can reuse ModelCheckpoints. However, at the moment, access to ModelCheckpoints
* object from CrossModelEnvironment is focused on load/restore of persisted state, and I don't want to intervene there right now. Besides,
* for the scenario at hand, we do not really need complete CheckpointState, just a reference to checkpoint model.
* @author Artem Tikhomirov
* @since 3.4
*/
public class ModelTransitions {
private TransitionTrace myActiveTransition;
private List<SModelReference> myCheckpointModels = new ArrayList<>(5);
public ModelTransitions() {
}
/**
* indicates we start at the given checkpoint, so that any future changes to the model treat this checkpoint as start/origin
* @param checkpoint last recorded checkpoint, or null if it's transformation of initial (i.e. not necessarily the @0 one, just no CP yet) model
* @param checkpointModel reference to checkpoint model, structurally (and node ids) identical to {@code transformationModel}
* @param transformationModel transient model with nodes deemed 'origin' of the checkpoint (we record their node identities as 'origins')
*/
public void newTransition(@Nullable Checkpoint checkpoint, @NotNull SModelReference checkpointModel, @NotNull SModel transformationModel) {
myActiveTransition = checkpoint == null ? new TransitionTrace(this) : new TransitionTrace(checkpoint, this);
myActiveTransition.reset(transformationModel);
myCheckpointModels.add(checkpointModel);
}
@NotNull
public TransitionTrace getActiveTransition() {
assert myActiveTransition != null;
return myActiveTransition;
}
@NotNull
public SModelReference getMostRecentCheckpointModel() {
return myCheckpointModels.get(myCheckpointModels.size()-1);
}
}