io.opencensus.metrics.data.AttachmentValue Maven / Gradle / Ivy
/*
* Copyright 2019, 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.metrics.data;
import com.google.auto.value.AutoValue;
import javax.annotation.concurrent.Immutable;
/**
* The value of {@link Exemplar} attachment.
*
* In Stats API we only provide one subclass {@link AttachmentValueString}. No other subclasses
* are added because we don't want to introduce dependencies on other libraries, for example Tracing
* APIs.
*
*
Other packages are free to extend this class to hold specific information. As an example, see
* {@code io.opencensus.contrib.exemplar.util.AttachmentValueSpanContext}.
*
* @since 0.20
*/
public abstract class AttachmentValue {
/**
* Returns the string attachment value.
*
* @return the string attachment value.
* @since 0.20
*/
public abstract String getValue();
/**
* String {@link AttachmentValue}.
*
* @since 0.20
*/
@AutoValue
@Immutable
public abstract static class AttachmentValueString extends AttachmentValue {
AttachmentValueString() {}
/**
* Creates an {@link AttachmentValueString}.
*
* @param value the string value.
* @return an {@code AttachmentValueString}.
* @since 0.20
*/
public static AttachmentValueString create(String value) {
return new AutoValue_AttachmentValue_AttachmentValueString(value);
}
}
}