com.google.instrumentation.trace.Samplers Maven / Gradle / Ivy
/*
* Copyright 2017, Google Inc.
* 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 com.google.instrumentation.trace;
import java.util.List;
import javax.annotation.Nullable;
/** Static class to access a set of pre-defined {@link Sampler Samplers}. */
public final class Samplers {
private static final Sampler ALWAYS_SAMPLE = new AlwaysSampleSampler();
private static final Sampler NEVER_SAMPLE = new NeverSampleSampler();
// No instance of this class.
private Samplers() {}
/**
* Returns a {@link Sampler} that always makes a "yes" decision on {@link Span} sampling.
*
* @return a {@code Sampler} that always makes a "yes" decision on {@code Span} sampling.
*/
public static Sampler alwaysSample() {
return ALWAYS_SAMPLE;
}
/**
* Returns a {@link Sampler} that always makes a "no" decision on {@link Span} sampling.
*
* @return a {@code Sampler} that always makes a "no" decision on {@code Span} sampling.
*/
public static Sampler neverSample() {
return NEVER_SAMPLE;
}
private static final class AlwaysSampleSampler extends Sampler {
private AlwaysSampleSampler() {}
// Returns always makes a "yes" decision on {@link Span} sampling.
@Override
protected boolean shouldSample(
@Nullable SpanContext parentContext,
boolean remoteParent,
TraceId traceId,
SpanId spanId,
String name,
List parentLinks) {
return true;
}
@Override
public String toString() {
return "AlwaysSampleSampler";
}
}
private static final class NeverSampleSampler extends Sampler {
private NeverSampleSampler() {}
// Returns always makes a "no" decision on {@link Span} sampling.
@Override
protected boolean shouldSample(
@Nullable SpanContext parentContext,
boolean remoteParent,
TraceId traceId,
SpanId spanId,
String name,
List parentLinks) {
return false;
}
@Override
public String toString() {
return "NeverSampleSampler";
}
}
}