/*
 * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.graalvm.graphio;

import java.util.Collection;
import java.util.Collections;

final class DefaultGraphBlocks implements GraphBlocks<Object, Object, Object> {
    private static final DefaultGraphBlocks DEFAULT = new DefaultGraphBlocks();

    private DefaultGraphBlocks() {
    }

    @SuppressWarnings("unchecked")
    public static <G, B, N> GraphBlocks<G, B, N> empty() {
        return (GraphBlocks<G, B, N>) DEFAULT;
    }

    @Override
    public Collection<? extends Void> blocks(Object graph) {
        return Collections.emptyList();
    }

    @Override
    public int blockId(Object block) {
        return -1;
    }

    @Override
    public Collection<? extends Object> blockNodes(Object info, Object block) {
        return Collections.emptyList();
    }

    @Override
    public Collection<? extends Object> blockSuccessors(Object block) {
        return Collections.emptyList();
    }
}