[platform] splits a Graph into pair of complementary interfaces

platform/util/src/com/intellij/util/graph/CachingSemiGraph.java

@@ -23,10 +23,14 @@ import java.util.*;
  * @author dsl
  */
 public class CachingSemiGraph<Node> implements GraphGenerator.SemiGraph<Node> {
+  public static <T> InboundSemiGraph<T> cache(InboundSemiGraph<T> original) {
+    return new CachingSemiGraph<T>(original);
+  }
+
   private final Set<Node> myNodes;
   private final Map<Node, Set<Node>> myIn;
 
-  public CachingSemiGraph(GraphGenerator.SemiGraph<Node> original) {
+  private CachingSemiGraph(InboundSemiGraph<Node> original) {
     myNodes = ContainerUtil.newLinkedHashSet(original.getNodes());
     myIn = new LinkedHashMap<Node, Set<Node>>();
     for (Node node : myNodes) {
@@ -36,10 +40,6 @@ public class CachingSemiGraph<Node> implements GraphGenerator.SemiGraph<Node> {
     }
   }
 
-  public static <T> CachingSemiGraph<T> create(GraphGenerator.SemiGraph<T> original) {
-    return new CachingSemiGraph<T>(original);
-  }
-
   @Override
   public Collection<Node> getNodes() {
     return myNodes;
@@ -49,4 +49,14 @@ public class CachingSemiGraph<Node> implements GraphGenerator.SemiGraph<Node> {
   public Iterator<Node> getIn(Node n) {
     return myIn.get(n).iterator();
   }
+
+  //<editor-fold desc="Deprecated stuff.">
+  public static <T> CachingSemiGraph<T> create(GraphGenerator.SemiGraph<T> original) {
+    return new CachingSemiGraph<T>((InboundSemiGraph<T>)original);
+  }
+
+  public CachingSemiGraph(GraphGenerator.SemiGraph<Node> original) {
+    this((InboundSemiGraph<Node>)original);
+  }
+  //</editor-fold>
 }

platform/util/src/com/intellij/util/graph/DFSTBuilder.java

@@ -30,7 +30,7 @@ import java.util.*;
  * @author dsl, ven
  */
 public class DFSTBuilder<Node> {
-  private final Graph<Node> myGraph;
+  private final OutboundSemiGraph<Node> myGraph;
   private final TObjectIntHashMap<Node> myNodeToNNumber; // node -> node number in topological order [0..size). Independent nodes are in reversed loading order (loading order is the graph.getNodes() order)
   private final Node[] myInvN; // node number in topological order [0..size) -> node
   private Couple<Node> myBackEdge;
@@ -42,8 +42,12 @@ public class DFSTBuilder<Node> {
   private final Node[] myInvT; // number in (enumerate all nodes scc by scc) order -> node
   private final Node[] myAllNodes;
 
-  @SuppressWarnings("unchecked")
   public DFSTBuilder(@NotNull Graph<Node> graph) {
+    this((OutboundSemiGraph<Node>)graph);
+  }
+
+  @SuppressWarnings("unchecked")
+  public DFSTBuilder(@NotNull OutboundSemiGraph<Node> graph) {
     myAllNodes = (Node[])graph.getNodes().toArray();
     myGraph = graph;
     int size = graph.getNodes().size();

platform/util/src/com/intellij/util/graph/Graph.java

@@ -21,7 +21,7 @@ import java.util.Iterator;
 /**
  * @author dsl
  */
-public interface Graph<Node> {
+public interface Graph<Node> extends InboundSemiGraph<Node>, OutboundSemiGraph<Node> {
   Collection<Node> getNodes();
 
   Iterator<Node> getIn(Node n);

platform/util/src/com/intellij/util/graph/GraphGenerator.java

@@ -21,25 +21,19 @@ import java.util.*;
  * @author dsl
  */
 public class GraphGenerator<Node> implements Graph<Node> {
-  public interface SemiGraph<Node> {
-    Collection<Node> getNodes();
-
-    Iterator<Node> getIn(Node n);
+  public static <T> Graph<T> generate(InboundSemiGraph<T> graph) {
+    return new GraphGenerator<T>(graph);
   }
 
-  private final SemiGraph<Node> myGraph;
+  private final InboundSemiGraph<Node> myGraph;
   private final Map<Node, Set<Node>> myOuts;
 
-  public GraphGenerator(SemiGraph<Node> graph) {
+  private GraphGenerator(InboundSemiGraph<Node> graph) {
     myGraph = graph;
     myOuts = new LinkedHashMap<Node, Set<Node>>();
     buildOuts();
   }
 
-  public static <T> GraphGenerator<T> create(SemiGraph<T> graph) {
-    return new GraphGenerator<T>(graph);
-  }
-
   private void buildOuts() {
     Collection<Node> nodes = myGraph.getNodes();
     for (Node node : nodes) {
@@ -73,4 +67,20 @@ public class GraphGenerator<Node> implements Graph<Node> {
   public Iterator<Node> getOut(Node n) {
     return myOuts.get(n).iterator();
   }
+
+  //<editor-fold desc="Deprecated stuff.">
+  public interface SemiGraph<Node> extends InboundSemiGraph<Node> {
+    Collection<Node> getNodes();
+
+    Iterator<Node> getIn(Node n);
+  }
+
+  public GraphGenerator(SemiGraph<Node> graph) {
+    this((InboundSemiGraph<Node>)graph);
+  }
+
+  public static <T> GraphGenerator<T> create(SemiGraph<T> graph) {
+    return new GraphGenerator<T>((InboundSemiGraph<T>)graph);
+  }
+  //</editor-fold>
 }

platform/util/src/com/intellij/util/graph/InboundSemiGraph.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2000-2016 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 com.intellij.util.graph;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+public interface InboundSemiGraph<Node> {
+  Collection<Node> getNodes();
+
+  Iterator<Node> getIn(Node n);
+}

platform/util/src/com/intellij/util/graph/OutboundSemiGraph.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2000-2016 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 com.intellij.util.graph;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+public interface OutboundSemiGraph<Node> {
+  Collection<Node> getNodes();
+
+  Iterator<Node> getOut(Node n);
+}