Scannable.Attr (Reactor Core 3.1.0.RC1)

java.lang.Object
- reactor.core.Scannable.Attr<T>

Type Parameters:

T - the type of data associated with an attribute

Enclosing interface:

Scannable
```
public static class Scannable.Attr<T>
extends Object
```
Base class for Scannable attributes, which all can define a meaningful default.

Field Summary

Fields
Modifier and Type	Field and Description
`static Scannable.Attr<Scannable>`	`ACTUAL` The direct dependent component downstream reference if any.
`static Scannable.Attr<Integer>`	`BUFFERED` A `Integer` attribute implemented by components with a backlog capacity.
`static Scannable.Attr<Boolean>`	`CANCELLED` A `Boolean` attribute indicating whether or not a downstream component has interrupted consuming this scanned component, e.g., a cancelled subscription.
`static Scannable.Attr<Integer>`	`CAPACITY` Return an an `Integer` capacity when no `PREFETCH` is defined or when an arbitrary maximum limit is applied to the backlog capacity of the scanned component.
`static Scannable.Attr<Boolean>`	`DELAY_ERROR` Delay_Error exposes a `Boolean` whether the scanned component actively supports error delaying if it manages a backlog instead of fast error-passing which might drop pending backlog.
`static Scannable.Attr<Throwable>`	`ERROR` a `Throwable` attribute which indicate an error state if the scanned component keeps track of it.
`static Scannable.Attr<Long>`	`LARGE_BUFFERED` Similar to `BUFFERED`, but reserved for operators that can hold a backlog of items that can grow beyond Integer.MAX_VALUE.
`static Scannable.Attr<String>`	`NAME` An arbitrary name given to the operator component.
`static Scannable.Attr<Scannable>`	`PARENT` Parent key exposes the direct upstream relationship of the scanned component.
`static Scannable.Attr<Integer>`	`PREFETCH` Prefetch is an `Integer` attribute defining the rate of processing in a component which has capacity to request and hold a backlog of data.
`static Scannable.Attr<Long>`	`REQUESTED_FROM_DOWNSTREAM` A `Long` attribute exposing the current pending demand of a downstream component.
`static Scannable.Attr<Stream<Tuple2<String,String>>>`	`TAGS` A `Stream` of `Tuple2` representing key/value pairs for tagged components.
`static Scannable.Attr<Boolean>`	`TERMINATED` A `Boolean` attribute indicating whether or not an upstream component terminated this scanned component.

Constructor Summary

Constructors
Modifier Constructor and Description

protected Attr(T defaultValue)

Constructors
Modifier	Constructor and Description
`protected`	`Attr(T defaultValue)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`T`	`defaultValue()` Meaningful and always applicable default value for the attribute, returned instead of null when a specific value hasn't been defined for a component.

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

- Field Detail
  - ACTUAL
```
public static final Scannable.Attr<Scannable> ACTUAL
```
    The direct dependent component downstream reference if any. Operators in Flux/Mono for instance delegate to a target Subscriber, which is going to be the actual chain navigated with this reference key.
    A reference chain downstream can be navigated via Scannable.actuals().
  - BUFFERED
```
public static final Scannable.Attr<Integer> BUFFERED
```
    A Integer attribute implemented by components with a backlog capacity. It will expose current queue size or similar related to user-provided held data. Note that some operators and processors CAN keep a backlog larger than Integer.MAX_VALUE, in which case the Attr LARGE_BUFFERED should be used instead. Such operators will attempt to serve a BUFFERED query but will return Integer.MIN_VALUE when actual buffer size is oversized for int.
  - CAPACITY
```
public static final Scannable.Attr<Integer> CAPACITY
```
    Return an an Integer capacity when no PREFETCH is defined or when an arbitrary maximum limit is applied to the backlog capacity of the scanned component. Integer.MAX_VALUE signal unlimited capacity.
    Note: This attribute usually resolves to a constant value.
  - CANCELLED
```
public static final Scannable.Attr<Boolean> CANCELLED
```
    A Boolean attribute indicating whether or not a downstream component has interrupted consuming this scanned component, e.g., a cancelled subscription. Note that it differs from TERMINATED which is intended for "normal" shutdown cycles.
  - DELAY_ERROR
```
public static final Scannable.Attr<Boolean> DELAY_ERROR
```
    Delay_Error exposes a Boolean whether the scanned component actively supports error delaying if it manages a backlog instead of fast error-passing which might drop pending backlog.
    Note: This attribute usually resolves to a constant value.
  - ERROR
```
public static final Scannable.Attr<Throwable> ERROR
```
    a Throwable attribute which indicate an error state if the scanned component keeps track of it.
  - LARGE_BUFFERED
```
public static final Scannable.Attr<Long> LARGE_BUFFERED
```
    Similar to BUFFERED, but reserved for operators that can hold a backlog of items that can grow beyond Integer.MAX_VALUE. These operators will also answer to a BUFFERED query up to the point where their buffer is actually too large, at which point they'll return Integer.MIN_VALUE, which serves as a signal that this attribute should be used instead. Defaults to null.
    Flux.flatMap, Flux.filterWhen, TopicProcessor, and Flux.window (with overlap) are known to use this attribute.
  - NAME
```
public static final Scannable.Attr<String> NAME
```
    An arbitrary name given to the operator component. Defaults to null.
  - PARENT
```
public static final Scannable.Attr<Scannable> PARENT
```
    Parent key exposes the direct upstream relationship of the scanned component. It can be a Publisher source to an operator, a Subscription to a Subscriber (main flow if ambiguous with inner Subscriptions like flatMap), a Scheduler to a Worker.
    Scannable.parents() can be used to navigate the parent chain.
  - PREFETCH
```
public static final Scannable.Attr<Integer> PREFETCH
```
    Prefetch is an Integer attribute defining the rate of processing in a component which has capacity to request and hold a backlog of data. It usually maps to a component capacity when no arbitrary CAPACITY is push. Integer.MAX_VALUE signal unlimited capacity and therefore unbounded demand.
    Note: This attribute usually resolves to a constant value.
  - REQUESTED_FROM_DOWNSTREAM
```
public static final Scannable.Attr<Long> REQUESTED_FROM_DOWNSTREAM
```
    A Long attribute exposing the current pending demand of a downstream component. Note that Long.MAX_VALUE indicates an unbounded (push-style) demand as specified in Subscription.request(long).
  - TERMINATED
```
public static final Scannable.Attr<Boolean> TERMINATED
```
    A Boolean attribute indicating whether or not an upstream component terminated this scanned component. e.g. a post onComplete/onError subscriber. By opposition to CANCELLED which determines if a downstream component interrupted this scanned component.
  - TAGS
```
public static final Scannable.Attr<Stream<Tuple2<String,String>>> TAGS
```
    A Stream of Tuple2 representing key/value pairs for tagged components. Defaults to null.
- Constructor Detail
  - Attr
```
protected Attr(@Nullable
               T defaultValue)
```
- Method Detail
  - defaultValue
```
@Nullable
public T defaultValue()
```
    Meaningful and always applicable default value for the attribute, returned instead of null when a specific value hasn't been defined for a component. null if no sensible generic default is available.
    
    Returns:
    
    the default value applicable to all components or null if none.

Class Scannable.Attr<T>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ACTUAL

BUFFERED

CAPACITY

CANCELLED

DELAY_ERROR

ERROR

LARGE_BUFFERED

NAME

PARENT

PREFETCH

REQUESTED_FROM_DOWNSTREAM

TERMINATED

TAGS

Constructor Detail

Attr

Method Detail

defaultValue