Brian O'Connor | 66630c8 | 2014-10-02 21:08:19 -0700 | [diff] [blame] | 1 | package org.onlab.onos.net.intent.impl; |
| 2 | |
| 3 | import static com.google.common.base.Preconditions.checkArgument; |
| 4 | |
| 5 | import java.util.Objects; |
| 6 | import java.util.concurrent.atomic.AtomicLong; |
| 7 | |
| 8 | import com.google.common.base.MoreObjects; |
| 9 | |
| 10 | /** |
| 11 | * A class representing an ID space. |
| 12 | */ |
| 13 | public final class IdBlock { |
| 14 | private final long start; |
| 15 | private final long size; |
| 16 | |
| 17 | private final AtomicLong currentId; |
| 18 | |
| 19 | /** |
| 20 | * Constructs a new ID block with the specified size and initial value. |
| 21 | * |
| 22 | * @param start initial value of the block |
| 23 | * @param size size of the block |
| 24 | * @throws IllegalArgumentException if the size is less than or equal to 0 |
| 25 | */ |
| 26 | public IdBlock(long start, long size) { |
| 27 | checkArgument(size > 0, "size should be more than 0, but %s", size); |
| 28 | |
| 29 | this.start = start; |
| 30 | this.size = size; |
| 31 | |
| 32 | this.currentId = new AtomicLong(start); |
| 33 | } |
| 34 | |
| 35 | // TODO: consider if this method is needed or not |
| 36 | /** |
| 37 | * Returns the initial value. |
| 38 | * |
| 39 | * @return initial value |
| 40 | */ |
| 41 | public long getStart() { |
| 42 | return start; |
| 43 | } |
| 44 | |
| 45 | // TODO: consider if this method is needed or not |
| 46 | /** |
| 47 | * Returns the last value. |
| 48 | * |
| 49 | * @return last value |
| 50 | */ |
| 51 | public long getEnd() { |
| 52 | return start + size - 1; |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Returns the block size. |
| 57 | * |
| 58 | * @return block size |
| 59 | */ |
| 60 | public long getSize() { |
| 61 | return size; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Returns the next ID in the block. |
| 66 | * |
| 67 | * @return next ID |
| 68 | * @throws UnavailableIdException if there is no available ID in the block. |
| 69 | */ |
| 70 | public long getNextId() { |
| 71 | final long id = currentId.getAndIncrement(); |
| 72 | if (id > getEnd()) { |
| 73 | throw new UnavailableIdException(String.format( |
| 74 | "used all IDs in allocated space (size: %d, end: %d, current: %d)", |
| 75 | size, getEnd(), id |
| 76 | )); |
| 77 | } |
| 78 | |
| 79 | return id; |
| 80 | } |
| 81 | |
| 82 | // TODO: Do we really need equals and hashCode? Should it contain currentId? |
| 83 | @Override |
| 84 | public boolean equals(Object o) { |
| 85 | if (this == o) { |
| 86 | return true; |
| 87 | } |
| 88 | if (o == null || getClass() != o.getClass()) { |
| 89 | return false; |
| 90 | } |
| 91 | |
| 92 | IdBlock that = (IdBlock) o; |
| 93 | return Objects.equals(this.start, that.start) |
| 94 | && Objects.equals(this.size, that.size) |
| 95 | && Objects.equals(this.currentId.get(), that.currentId.get()); |
| 96 | } |
| 97 | |
| 98 | @Override |
| 99 | public int hashCode() { |
| 100 | return Objects.hash(start, size, currentId); |
| 101 | } |
| 102 | |
| 103 | @Override |
| 104 | public String toString() { |
| 105 | return MoreObjects.toStringHelper(getClass()) |
| 106 | .add("start", start) |
| 107 | .add("size", size) |
| 108 | .add("currentId", currentId) |
| 109 | .toString(); |
| 110 | } |
| 111 | } |