io.opencensus.trace.Sampler Maven / Gradle / Ivy
/*
* Copyright 2017, OpenCensus Authors
*
* 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 io.opencensus.trace;
import java.util.List;
import javax.annotation.Nullable;
/**
* Sampler is used to make decisions on {@link Span} sampling.
*
* @since 0.5
*/
public abstract class Sampler {
/**
* Called during {@link Span} creation to make a sampling decision.
*
* @param parentContext the parent span's {@link SpanContext}. {@code null} if this is a root
* span.
* @param hasRemoteParent {@code true} if the parent {@code Span} is remote. {@code null} if this
* is a root span.
* @param traceId the {@link TraceId} for the new {@code Span}. This will be identical to that in
* the parentContext, unless this is a root span.
* @param spanId the {@link SpanId} for the new {@code Span}.
* @param name the name of the new {@code Span}.
* @param parentLinks the parentLinks associated with the new {@code Span}.
* @return {@code true} if the {@code Span} is sampled.
* @since 0.5
*/
public abstract boolean shouldSample(
@Nullable SpanContext parentContext,
@Nullable Boolean hasRemoteParent,
TraceId traceId,
SpanId spanId,
String name,
List parentLinks);
/**
* Returns the description of this {@code Sampler}. This may be displayed on debug pages or in the
* logs.
*
* Example: "ProbabilitySampler{0.000100}"
*
* @return the description of this {@code Sampler}.
* @since 0.6
*/
public abstract String getDescription();
}