| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.htrace.core; |
| |
| import java.util.concurrent.ThreadLocalRandom; |
| |
| /** |
| * Uniquely identifies an HTrace span. |
| * |
| * Span IDs are 128 bits in total. The upper 64 bits of a span ID is the same |
| * as the upper 64 bits of the parent span, if there is one. The lower 64 bits |
| * are always random. |
| */ |
| public final class SpanId implements Comparable<SpanId> { |
| private static final int SPAN_ID_STRING_LENGTH = 32; |
| private final long high; |
| private final long low; |
| |
| /** |
| * The invalid span ID, which is all zeroes. |
| * |
| * It is also the "least" span ID in the sense that it is considered |
| * smaller than any other span ID. |
| */ |
| public static SpanId INVALID = new SpanId(0, 0); |
| |
| private static long nonZeroRand64() { |
| while (true) { |
| long r = ThreadLocalRandom.current().nextLong(); |
| if (r != 0) { |
| return r; |
| } |
| } |
| } |
| |
| public static SpanId fromRandom() { |
| return new SpanId(nonZeroRand64(), nonZeroRand64()); |
| } |
| |
| public static SpanId fromString(String str) { |
| if (str.length() != SPAN_ID_STRING_LENGTH) { |
| throw new RuntimeException("Invalid SpanID string: length was not " + |
| SPAN_ID_STRING_LENGTH); |
| } |
| long high = |
| ((Long.parseLong(str.substring(0, 8), 16)) << 32) | |
| (Long.parseLong(str.substring(8, 16), 16)); |
| long low = |
| ((Long.parseLong(str.substring(16, 24), 16)) << 32) | |
| (Long.parseLong(str.substring(24, 32), 16)); |
| return new SpanId(high, low); |
| } |
| |
| public SpanId(long high, long low) { |
| this.high = high; |
| this.low = low; |
| } |
| |
| public long getHigh() { |
| return high; |
| } |
| |
| public long getLow() { |
| return low; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (!(o instanceof SpanId)) { |
| return false; |
| } |
| SpanId other = (SpanId)o; |
| return ((other.high == high) && (other.low == low)); |
| } |
| |
| @Override |
| public int compareTo(SpanId other) { |
| int cmp = compareAsUnsigned(high, other.high); |
| if (cmp != 0) { |
| return cmp; |
| } |
| return compareAsUnsigned(low, other.low); |
| } |
| |
| private static int compareAsUnsigned(long a, long b) { |
| boolean aSign = a < 0; |
| boolean bSign = b < 0; |
| if (aSign != bSign) { |
| if (aSign) { |
| return 1; |
| } else { |
| return -1; |
| } |
| } |
| if (aSign) { |
| a = -a; |
| b = -b; |
| } |
| if (a < b) { |
| return -1; |
| } else if (a > b) { |
| return 1; |
| } else { |
| return 0; |
| } |
| } |
| |
| @Override |
| public int hashCode() { |
| return (int)((0xffffffff & (high >> 32))) ^ |
| (int)((0xffffffff & (high >> 0))) ^ |
| (int)((0xffffffff & (low >> 32))) ^ |
| (int)((0xffffffff & (low >> 0))); |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("%08x%08x%08x%08x", |
| (0x00000000ffffffffL & (high >> 32)), |
| (0x00000000ffffffffL & high), |
| (0x00000000ffffffffL & (low >> 32)), |
| (0x00000000ffffffffL & low)); |
| } |
| |
| public boolean isValid() { |
| return (high != 0) || (low != 0); |
| } |
| |
| public SpanId newChildId() { |
| return new SpanId(high, nonZeroRand64()); |
| } |
| } |