Java tutorial
/* * Copyright 2009 the original author or authors. * * 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 org.gradle.cache.internal.btree; import com.google.common.primitives.Longs; public class BlockPointer implements Comparable<BlockPointer> { private static final BlockPointer NULL = new BlockPointer(-1); public static BlockPointer start() { return NULL; } public static BlockPointer pos(long pos) { if (pos < -1) { throw new CorruptedCacheException("block pointer must be >= -1, but was" + pos); } if (pos == -1) { return NULL; } return new BlockPointer(pos); } private final long pos; private BlockPointer(long pos) { this.pos = pos; } public boolean isNull() { return pos < 0; } public long getPos() { return pos; } @Override public String toString() { return String.valueOf(pos); } @Override public boolean equals(Object obj) { if (obj == null || obj.getClass() != getClass()) { return false; } BlockPointer other = (BlockPointer) obj; return pos == other.pos; } @Override public int hashCode() { return Longs.hashCode(pos); } public int compareTo(BlockPointer o) { return Longs.compare(pos, o.pos); } }