ModelChange.java

package jetbrains.mps.vcs.diff.changes;

/*Generated by MPS */

import jetbrains.mps.vcs.diff.ChangeSet;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.mps.openapi.model.SNodeId;
import org.jetbrains.mps.openapi.model.SModel;
import org.jetbrains.mps.openapi.model.SNodeReference;
import jetbrains.mps.internal.collections.runtime.Sequence;
import jetbrains.mps.internal.collections.runtime.ISelector;
import jetbrains.mps.internal.collections.runtime.IVisitor;

public abstract class ModelChange {
  private ChangeSet myChangeSet;
  private ModelChange myOpposite = null;
  protected ModelChange(@NotNull ChangeSet changeSet) {
    myChangeSet = changeSet;
  }
  @NotNull
  public final ChangeSet getChangeSet() {
    return myChangeSet;
  }
  @Nullable
  public SNodeId getRootId() {
    return null;
  }
  public abstract void apply(@NotNull SModel model, @NotNull NodeCopier nodeCopier);
  public ModelChange getOppositeChange() {
    if (myOpposite == null) {
      myOpposite = createOppositeChange();
      myOpposite.myOpposite = this;
    }
    return myOpposite;
  }
  @NotNull
  protected abstract ModelChange createOppositeChange();
  @NotNull
  public abstract ChangeType getType();
  public boolean isNonConflicting() {
    // true - change can never conflict with other change and should be ignored if connected change exists (e.g. resolveInfo change) 
    return getMergeHint() != null;
  }
  @Nullable
  public SNodeReference getMergeHint() {
    return null;
  }
  @Override
  public abstract String toString();
  public abstract String getDescription();
  public static void rollbackChanges(Iterable<ModelChange> changes) {
    assert Sequence.fromIterable(changes).isNotEmpty();
    final SModel model = Sequence.fromIterable(changes).first().getChangeSet().getNewModel();
    final NodeCopier nc = new NodeCopier(model);
    Iterable<ModelChange> oppositeChanges = Sequence.fromIterable(changes).select(new ISelector<ModelChange, ModelChange>() {
      public ModelChange select(ModelChange ch) {
        return ch.getOppositeChange();
      }
    });
    for (ModelChange ch : Sequence.fromIterable(oppositeChanges)) {
      if (ch instanceof NodeGroupChange) {
        ((NodeGroupChange) ch).prepare();
      }
    }
    Sequence.fromIterable(oppositeChanges).visitAll(new IVisitor<ModelChange>() {
      public void visit(ModelChange ch) {
        ch.apply(model, nc);
      }
    });
    nc.restoreIds(true);
  }
}