| /* |
| * Copyright 2014-present Open Networking Foundation |
| * |
| * 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.onosproject.core; |
| |
| import com.google.common.base.MoreObjects; |
| |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| /** |
| * A class representing an ID space. |
| */ |
| public final class IdBlock { |
| private final long start; |
| private final long size; |
| |
| private final AtomicLong currentId; |
| |
| /** |
| * Constructs a new ID block with the specified size and initial value. |
| * |
| * @param start initial value of the block |
| * @param size size of the block |
| * @throws IllegalArgumentException if the size is less than or equal to 0 |
| */ |
| public IdBlock(long start, long size) { |
| checkArgument(size > 0, "size should be more than 0, but %s", size); |
| |
| this.start = start; |
| this.size = size; |
| |
| this.currentId = new AtomicLong(start); |
| } |
| |
| /** |
| * Returns the initial value. |
| * |
| * @return initial value |
| */ |
| private long getStart() { |
| return start; |
| } |
| |
| /** |
| * Returns the last value. |
| * |
| * @return last value |
| */ |
| private long getEnd() { |
| return start + size - 1; |
| } |
| |
| /** |
| * Returns the block size. |
| * |
| * @return block size |
| */ |
| public long getSize() { |
| return size; |
| } |
| |
| /** |
| * Returns the next ID in the block. |
| * |
| * @return next ID |
| * @throws UnavailableIdException if there is no available ID in the block. |
| */ |
| public long getNextId() { |
| final long id = currentId.getAndIncrement(); |
| if (id > getEnd()) { |
| throw new UnavailableIdException(String.format( |
| "used all IDs in allocated space (size: %d, end: %d, current: %d)", |
| size, getEnd(), id |
| )); |
| } |
| |
| return id; |
| } |
| |
| @Override |
| public String toString() { |
| return MoreObjects.toStringHelper(getClass()) |
| .add("start", start) |
| .add("size", size) |
| .add("currentId", currentId) |
| .toString(); |
| } |
| } |