Tracer (htrace-core4 4.2.0-incubating API)

java.lang.Object
- org.apache.htrace.core.Tracer

All Implemented Interfaces:

Closeable, AutoCloseable
```
public class Tracer
extends Object
implements Closeable
```
Use a Tracer instance inside a 'process' to collect and distribute its trace Spans. Example processes are an HDFS DataNode or an HBase RegionServer. A Tracer instance is your one-stop shop for all things tracing.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Tracer.Builder

Nested Classes
Modifier and Type	Class and Description
`static class`	`Tracer.Builder`

Field Summary

Fields
Modifier and Type Field and Description

static String SAMPLER_CLASSES_KEY

static String SPAN_RECEIVER_CLASSES_KEY

Fields
Modifier and Type	Field and Description
`static String`	`SAMPLER_CLASSES_KEY`
`static String`	`SPAN_RECEIVER_CLASSES_KEY`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`addSampler(Sampler sampler)` Add a new Sampler.
`void`	`close()`
`static Tracer`	`curThreadTracer()`
`boolean`	`equals(Object other)` Compare two tracer objects.
`static Span`	`getCurrentSpan()`
`static SpanId`	`getCurrentSpanId()`
`Sampler[]`	`getSamplers()` Returns an array of all the current Samplers.
`String`	`getTracerId()`
`TracerPool`	`getTracerPool()`
`int`	`hashCode()` Get the hash code of a Tracer object.
`TraceScope`	`newNullScope()` Return a null trace scope.
`TraceScope`	`newScope(String description)` Create a new trace scope.
`TraceScope`	`newScope(String description, SpanId parentId)` Create a new trace scope.
`TraceExecutorService`	`newTraceExecutorService(ExecutorService impl)`
`TraceExecutorService`	`newTraceExecutorService(ExecutorService impl, String scopeName)`
`ScheduledTraceExecutorService`	`newTraceExecutorService(ScheduledExecutorService impl)`
`ScheduledTraceExecutorService`	`newTraceExecutorService(ScheduledExecutorService impl, String scopeName)`
`boolean`	`removeSampler(Sampler sampler)` Remove a Sampler.
`String`	`toString()`
`<V> Callable<V>`	`wrap(Callable<V> callable, String description)` Wrap the callable in a TraceCallable, if tracing.
`Runnable`	`wrap(Runnable runnable, String description)` Wrap the runnable in a TraceRunnable, if tracing

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - SPAN_RECEIVER_CLASSES_KEY
```
public static final String SPAN_RECEIVER_CLASSES_KEY
```
    See Also:
    
    Constant Field Values
  - SAMPLER_CLASSES_KEY
```
public static final String SAMPLER_CLASSES_KEY
```
    See Also:
    
    Constant Field Values
- Method Detail
  - curThreadTracer
```
public static Tracer curThreadTracer()
```
    Returns:
    
    If the current thread is tracing, this function returns the Tracer that is being used; otherwise, it returns null.
  - getTracerId
```
public String getTracerId()
```
  - newScope
```
public TraceScope newScope(String description,
                           SpanId parentId)
```
    Create a new trace scope. If there are no scopes above the current scope, we will apply our configured samplers. Otherwise, we will create a trace Span only if this thread is already tracing, or if the passed parentID was valid.
    
    Parameters:
    
    description - The description of the new span to create.
    
    parentId - If this is a valid span ID, it will be added to the parents of the new span we create.
    
    Returns:
    
    The new trace scope.
  - newScope
```
public TraceScope newScope(String description)
```
    Create a new trace scope. If there are no scopes above the current scope, we will apply our configured samplers. Otherwise, we will create a trace Span only if this thread is already tracing.
    
    Parameters:
    
    description - The description of the new span to create.
    
    Returns:
    
    The new trace scope.
  - newNullScope
```
public TraceScope newNullScope()
```
    Return a null trace scope.
    
    Returns:
    
    The null trace scope.
  - wrap
```
public <V> Callable<V> wrap(Callable<V> callable,
                            String description)
```
    Wrap the callable in a TraceCallable, if tracing.
    
    Type Parameters:
    
    V - The subclass of callable.
    
    Parameters:
    
    callable - The callable to wrap.
    
    description - A description of the callable, or null if there is no description.
    
    Returns:
    
    The callable provided, wrapped if tracing, 'callable' if not.
  - wrap
```
public Runnable wrap(Runnable runnable,
                     String description)
```
    Wrap the runnable in a TraceRunnable, if tracing
    
    Parameters:
    
    runnable - The runnable to wrap.
    
    description - A description of the runnable, or null if there is no description.
    
    Returns:
    
    The runnable provided, wrapped if tracing, 'runnable' if not.
  - newTraceExecutorService
```
public TraceExecutorService newTraceExecutorService(ExecutorService impl)
```
  - newTraceExecutorService
```
public TraceExecutorService newTraceExecutorService(ExecutorService impl,
                                                    String scopeName)
```
  - newTraceExecutorService
```
public ScheduledTraceExecutorService newTraceExecutorService(ScheduledExecutorService impl)
```
  - newTraceExecutorService
```
public ScheduledTraceExecutorService newTraceExecutorService(ScheduledExecutorService impl,
                                                             String scopeName)
```
  - getTracerPool
```
public TracerPool getTracerPool()
```
  - getSamplers
```
public Sampler[] getSamplers()
```
    Returns an array of all the current Samplers. Note that if the current Samplers change, those changes will not be reflected in this array. In other words, this array may be stale.
    
    Returns:
    
    The current samplers.
  - addSampler
```
public boolean addSampler(Sampler sampler)
```
    Add a new Sampler.
    
    Parameters:
    
    sampler - The new sampler to add. You cannot add a particular Sampler object more than once. You may add multiple Sampler objects of the same type, although this is not recommended.
    
    Returns:
    
    True if the sampler was added; false if it already had been added earlier.
  - removeSampler
```
public boolean removeSampler(Sampler sampler)
```
    Remove a Sampler.
    
    Parameters:
    
    sampler - The sampler to remove.
    
    Returns:
    
    True only if the sampler was removed.
  - getCurrentSpan
```
public static Span getCurrentSpan()
```
  - getCurrentSpanId
```
public static SpanId getCurrentSpanId()
```
  - close
```
public void close()
```
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
  - hashCode
```
public int hashCode()
```
    Get the hash code of a Tracer object. This hash code is based on object identity. This is used in TracerPool to create a hash table of Tracers.
    
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object other)
```
    Compare two tracer objects. Tracer objects are always compared by object equality. This is used in TracerPool to create a hash table of Tracers.
    
    Overrides:
    
    equals in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Tracer

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

SPAN_RECEIVER_CLASSES_KEY

SAMPLER_CLASSES_KEY

Method Detail

curThreadTracer

getTracerId

newScope

newScope

newNullScope

wrap

wrap

newTraceExecutorService

newTraceExecutorService

newTraceExecutorService

newTraceExecutorService

getTracerPool

getSamplers

addSampler

removeSampler

getCurrentSpan

getCurrentSpanId

close

hashCode

equals

toString