com.google.instrumentation.stats

Class StatsContextFactory

java.lang.Object

com.google.instrumentation.stats.StatsContextFactory

public abstract class StatsContextFactory
extends Object

Factory class for StatsContext.

Constructor Summary

Constructors

Constructor and Description
StatsContextFactory()

Method Summary

Modifier and Type	Method and Description
abstract StatsContext	deserialize(InputStream input) Creates a StatsContext from the given on-the-wire encoded representation.
StatsContext	getCurrentStatsContext() Get current StatsContext from current gRPC Context.
abstract StatsContext	getDefault() Returns the default StatsContext.
NonThrowingCloseable	withStatsContext(StatsContext statsContext) Enters the scope of code where the given StatsContext is in the current Context, and returns an object that represents that scope.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StatsContextFactory

public StatsContextFactory()

Method Detail

deserialize

public abstract StatsContext deserialize(InputStream input)
                                  throws IOException

Creates a StatsContext from the given on-the-wire encoded representation.

Should be the inverse of StatsContext.serialize(java.io.OutputStream). The serialized representation should be based on the StatsContext binary representation.

Parameters:

input - on-the-wire representation of a StatsContext

Returns:

a StatsContext deserialized from input

Throws:

IOException

getDefault

public abstract StatsContext getDefault()

Returns the default StatsContext.

getCurrentStatsContext

public final StatsContext getCurrentStatsContext()

Get current StatsContext from current gRPC Context.

Returns:

the current StatsContext from io.grpc.Context, or the default StatsContext if there's no StatsContext associated with current io.grpc.Context.

withStatsContext

public final NonThrowingCloseable withStatsContext(StatsContext statsContext)

Enters the scope of code where the given StatsContext is in the current Context, and returns an object that represents that scope. The scope is exited when the returned object is closed.

Supports try-with-resource idiom.

Example of usage:

 private final StatsContextFactory statsCtxFactory =
     checkNotNull(Stats.getStatsContextFactory(), "statsCtxFactory");
 void doWork() {
   // Construct a new StatsContext with required tags to be set into current context.
   StatsContext statsCtx = statsCtxFactory.getCurrentStatsContext().with(tagKey, tagValue);
   try (NonThrowingCloseable scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx)) {
     doSomeOtherWork();  // Here "scopedStatsCtx" is the current StatsContext.
   }
 }
 

Prior to Java SE 7, you can use a finally block to ensure that a resource is closed regardless of whether the try statement completes normally or abruptly.

Example of usage prior to Java SE7:

 private final StatsContextFactory statsCtxFactory =
     checkNotNull(Stats.getStatsContextFactory(), "statsCtxFactory");
 void doWork() {
   // Construct a new StatsContext with required tags to be set into current context.
   StatsContext statsCtx = statsCtxFactory.getCurrentStatsContext().with(tagKey, tagValue);
   NonThrowingCloseable scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx);
   try {
     doSomeOtherWork();  // Here "scopedStatsCtx" is the current StatsContext.
   } finally {
     scopedStatsCtx.close();
   }
 }
 

Parameters:

statsContext - The StatsContext to be set to the current Context.

Returns:

an object that defines a scope where the given StatsContext will be set to the current Context.

Throws:

NullPointerException - if statsContext is null.