1 /*
   2  * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.graphio;
  24 
  25 import java.util.Collection;
  26 import java.util.Collections;
  27 
  28 final class DefaultGraphBlocks implements GraphBlocks<Object, Object, Object> {
  29     private static final DefaultGraphBlocks DEFAULT = new DefaultGraphBlocks();
  30 
  31     private DefaultGraphBlocks() {
  32     }
  33 
  34     @SuppressWarnings("unchecked")
  35     public static <G, B, N> GraphBlocks<G, B, N> empty() {
  36         return (GraphBlocks<G, B, N>) DEFAULT;
  37     }
  38 
  39     @Override
  40     public Collection<? extends Void> blocks(Object graph) {
  41         return Collections.emptyList();
  42     }
  43 
  44     @Override
  45     public int blockId(Object block) {
  46         return -1;
  47     }
  48 
  49     @Override
  50     public Collection<? extends Object> blockNodes(Object info, Object block) {
  51         return Collections.emptyList();
  52     }
  53 
  54     @Override
  55     public Collection<? extends Object> blockSuccessors(Object block) {
  56         return Collections.emptyList();
  57     }
  58 }