/* * Copyright 2003-2014 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; import org.jetbrains.annotations.NotNull; import org.jetbrains.annotations.Nullable; import org.jetbrains.mps.openapi.model.SModelReference; import org.jetbrains.mps.openapi.model.SNode; import org.jetbrains.mps.openapi.model.SNodeId; import org.jetbrains.mps.openapi.model.SNodeReference; import java.util.List; /** * 2nd generation of generation (pun, sorry) trace facility. * The idea is to record actual change rather to track each step with strict open/close semantic. * Primary distinction is: lightweight (keep minimum), less use burden (few calls), multithread-friendly * * <p> * Design note: * Unlike existing IGenerationTracer, which is (singleton) project component, new trace facility * is associated with transient model/module, and there's no need to pass it explicitly through GenerationOption * </p> * @author Artem Tikhomirov */ public interface GenerationTrace { void nextStep(@NotNull SModelReference input, @NotNull SModelReference output); void dropStep(@NotNull SModelReference input, @NotNull SModelReference output); void trace(@Nullable SNodeId input, @NotNull List<SNodeId> output, @NotNull SNodeReference templateNode); void walkForward(SNode node, @NotNull Visitor v); void walkBackward(SNode node, @NotNull Visitor v); public interface Visitor { void beginStep(@NotNull SModelReference input, @NotNull SModelReference output); // added, removed (although latter is hard to detect)? void change(@NotNull SNodeReference input, @NotNull SNodeReference output, @NotNull SNodeReference template); void endStep(@NotNull SModelReference input, @NotNull SModelReference output); } public class NoOp implements GenerationTrace { @Override public void nextStep(@NotNull SModelReference input, @NotNull SModelReference output) { } @Override public void dropStep(@NotNull SModelReference input, @NotNull SModelReference output) { } @Override public void trace(@Nullable SNodeId input, @NotNull List<SNodeId> output, @NotNull SNodeReference templateNode) { } @Override public void walkForward(SNode node, Visitor v) { // no-op } @Override public void walkBackward(SNode node, Visitor v) { // no-op } } }