| package net.onrc.onos.core.util; |
| |
| import com.google.common.base.Objects; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| /** |
| * A class representing an ID space. This class is not thread-safe. |
| */ |
| public final class IdBlock { |
| private final long start; |
| private final long size; |
| |
| private long 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 = start; |
| } |
| |
| // TODO: consider if this method is needed or not |
| /** |
| * Returns the initial value. |
| * |
| * @return initial value |
| */ |
| public long getStart() { |
| return start; |
| } |
| |
| // TODO: consider if this method is needed or not |
| /** |
| * Returns the last value. |
| * |
| * @return last value |
| */ |
| public 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() { |
| if (currentId > getEnd()) { |
| throw new UnavailableIdException(String.format( |
| "use all IDs in allocated space (size: %d, end: %d, current: %d)", |
| size, getEnd(), currentId |
| )); |
| } |
| long id = currentId; |
| currentId++; |
| |
| return id; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (o == null || getClass() != o.getClass()) { |
| return false; |
| } |
| |
| IdBlock that = (IdBlock) o; |
| return Objects.equal(this.start, that.start) |
| && Objects.equal(this.size, that.size) |
| && Objects.equal(this.currentId, that.currentId); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hashCode(start, size, currentId); |
| } |
| |
| @Override |
| public String toString() { |
| return Objects.toStringHelper(getClass()) |
| .add("start", start) |
| .add("size", size) |
| .add("currentId", currentId) |
| .toString(); |
| } |
| } |