public void setMergingStrategy( MergeStrategy mergingStrategy ) {
if (mergingStrategy != null) {
this.mergingStrategy = mergingStrategy;
} else {
if (this.sourceProjections.size() == 1 && this.sourceProjections.get(0).isSimple()) {
this.mergingStrategy = new OneContributionMergeStrategy();
} else {
this.mergingStrategy = new SimpleMergeStrategy();
}
}
assert this.mergingStrategy != null;