AttributeKey (OpenTelemetry API)

Type Parameters:

T - The type of value that can be set with the key.
```
@Immutable
public interface AttributeKey<T>
```
This interface provides a handle for setting the values of Attributes. The type of value that can be set with an implementation of this key is denoted by the type parameter.
Implementations MUST be immutable, as these are used as the keys to Maps.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`static AttributeKey<List<Boolean>>`	`booleanArrayKey(String key)`	Returns a new AttributeKey for List<Boolean> valued attributes.
`static AttributeKey<Boolean>`	`booleanKey(String key)`	Returns a new AttributeKey for Boolean valued attributes.
`static AttributeKey<List<Double>>`	`doubleArrayKey(String key)`	Returns a new AttributeKey for List<Double> valued attributes.
`static AttributeKey<Double>`	`doubleKey(String key)`	Returns a new AttributeKey for Double valued attributes.
`String`	`getKey()`	Returns the underlying String representation of the key.
`AttributeType`	`getType()`	Returns the type of attribute for this key.
`static AttributeKey<List<Long>>`	`longArrayKey(String key)`	Returns a new AttributeKey for List<Long> valued attributes.
`static AttributeKey<Long>`	`longKey(String key)`	Returns a new AttributeKey for Long valued attributes.
`static AttributeKey<List<String>>`	`stringArrayKey(String key)`	Returns a new AttributeKey for List<String> valued attributes.
`static AttributeKey<String>`	`stringKey(String key)`	Returns a new AttributeKey for String valued attributes.

- Method Detail
  - getKey
```
String getKey()
```
    Returns the underlying String representation of the key.
  - getType
```
AttributeType getType()
```
    Returns the type of attribute for this key. Useful for building switch statements.
  - stringKey
```
static AttributeKey<String> stringKey(String key)
```
    Returns a new AttributeKey for String valued attributes.
  - booleanKey
```
static AttributeKey<Boolean> booleanKey(String key)
```
    Returns a new AttributeKey for Boolean valued attributes.
  - longKey
```
static AttributeKey<Long> longKey(String key)
```
    Returns a new AttributeKey for Long valued attributes.
  - doubleKey
```
static AttributeKey<Double> doubleKey(String key)
```
    Returns a new AttributeKey for Double valued attributes.
  - stringArrayKey
```
static AttributeKey<List<String>> stringArrayKey(String key)
```
    Returns a new AttributeKey for List<String> valued attributes.
  - booleanArrayKey
```
static AttributeKey<List<Boolean>> booleanArrayKey(String key)
```
    Returns a new AttributeKey for List<Boolean> valued attributes.
  - longArrayKey
```
static AttributeKey<List<Long>> longArrayKey(String key)
```
    Returns a new AttributeKey for List<Long> valued attributes.
  - doubleArrayKey
```
static AttributeKey<List<Double>> doubleArrayKey(String key)
```
    Returns a new AttributeKey for List<Double> valued attributes.