oap-server/analyzer/agent-analyzer/src/main/java/org/apache/skywalking/oap/server/analyzer/provider/trace/parser/listener/TraceSegmentSampler.java

/*
 * 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.skywalking.oap.server.analyzer.provider.trace.parser.listener;

import org.apache.skywalking.oap.server.analyzer.provider.trace.TraceSampleRateWatcher;

/**
 * The sampler makes the sampling mechanism works at backend side. Sample result: [0,sampleRate) sampled, (sampleRate,~)
 * ignored
 */
public class TraceSegmentSampler {
    private TraceSampleRateWatcher traceSampleRateWatcher;

    public TraceSegmentSampler(TraceSampleRateWatcher traceSampleRateWatcher) {
        this.traceSampleRateWatcher = traceSampleRateWatcher;
    }

    public boolean shouldSample(String traceId) {
        return Math.abs(traceId.hashCode()) % 10000 < traceSampleRateWatcher.getSampleRate();
    }
}