@Override
public final void merge(MergeOperation<ASTNodeArtifact> operation, MergeContext context)
throws IOException, InterruptedException {
Objects.requireNonNull(operation, "operation must not be null!");
Objects.requireNonNull(context, "context must not be null!");
MergeStrategy<ASTNodeArtifact> astNodeStrategy = new ASTNodeStrategy();
if (LOG.isDebugEnabled()) {
LOG.debug("Using strategy: " + astNodeStrategy);
}
MergeTriple<ASTNodeArtifact> triple = operation.getMergeTriple();
ASTNodeArtifact left = triple.getLeft();
ASTNodeArtifact right = triple.getRight();
ASTNodeArtifact target = operation.getTarget();
boolean safeMerge = true;
int numChildNoTransform;
try {
numChildNoTransform = target.astnode.getClass().newInstance().getNumChildNoTransform();
} catch (InstantiationException | IllegalAccessException e) {
throw new RuntimeException();
}
if (!isRoot() && numChildNoTransform > 0) {
// this language element has a fixed number of children, we need to be careful with this one
boolean leftChanges = left.hasChanges(false);
boolean rightChanges = right.hasChanges(false);
if (leftChanges && rightChanges) {
if (LOG.isTraceEnabled()) {
LOG.trace("Target " + target.getId() + " expects a fixed amount of children.");
LOG.trace("Both " + left.getId() + " and " + right.getId() + " contain changes.");
LOG.trace("We will report a conflict instead of performing the merge.");
}
safeMerge = false;
// to be safe, we will report a conflict instead of merging
ASTNodeArtifact targetParent = target.getParent();
targetParent.removeChild(target);
Operation<ASTNodeArtifact> conflictOp =
new ConflictOperation<>(left, left, right, targetParent);
conflictOp.apply(context);
}
}
if (safeMerge) {
astNodeStrategy.merge(operation, context);
}
if (!context.isQuiet() && context.hasOutput()) {
System.out.print(context.getStdIn());
}
}