Package com.mongodb

Interface RequestContext

public interface RequestContext

The request context, useful for implementing distributed tracing.

Since:

4.4

See Also:

MongoClientSettings.getContextProvider()

Method Summary

Modifier and Type	Method	Description
void	delete(Object key)	Delete the given key and its associated value from the RequestContext.
default <T> T	get(Class<T> key)	Resolve a value given a type key within the RequestContext.
<T> T	get(Object key)	Resolve a value given a key that exists within the RequestContext, or throw a NoSuchElementException if the key is not present.
default <T> T	getOrDefault(Object key, T defaultValue)	Resolve a value given a key within the RequestContext.
default <T> Optional<T>	getOrEmpty(Object key)	Resolve a value given a key within the RequestContext.
boolean	hasKey(Object key)	Return true if a particular key resolves to a value within the RequestContext.
boolean	isEmpty()	Return true if the RequestContext is empty.
void	put(Object key, Object value)	Modifies this instance with the given key and value.
default void	putNonNull(Object key, Object valueOrNull)	Modifies this instance with the given key and value only if the value is not null.
int	size()	Return the size of this RequestContext, the number of key/value pairs stored inside it.
Stream<Map.Entry<Object,Object>>	stream()	Stream key/value pairs from this RequestContext

Method Detail

get

<T> T get(Object key)

Resolve a value given a key that exists within the RequestContext, or throw a NoSuchElementException if the key is not present.

Type Parameters:

T - an unchecked casted generic for fluent typing convenience

Parameters:

key - a lookup key to resolve the value within the context

Returns:

the value resolved for this key (throws if key not found)

Throws:

NoSuchElementException - when the given key is not present

See Also:

getOrDefault(Object, Object), getOrEmpty(Object), hasKey(Object)

get

default <T> T get(Class<T> key)

Resolve a value given a type key within the RequestContext.

Type Parameters:

T - an unchecked casted generic for fluent typing convenience

Parameters:

key - a type key to resolve the value within the context

Returns:

the value resolved for this type key (throws if key not found)

Throws:

NoSuchElementException - when the given type key is not present

See Also:

getOrDefault(Object, Object), getOrEmpty(Object)

getOrDefault

@Nullable
default <T> T getOrDefault(Object key,
                           @Nullable
                           T defaultValue)

Resolve a value given a key within the RequestContext. If unresolved return the passed default value.

Type Parameters:

T - an unchecked casted generic for fluent typing convenience

Parameters:

key - a lookup key to resolve the value within the context

defaultValue - a fallback value if key doesn't resolve

Returns:

the value resolved for this key, or the given default if not present

getOrEmpty

default <T> Optional<T> getOrEmpty(Object key)

Resolve a value given a key within the RequestContext.

Type Parameters:

T - an unchecked casted generic for fluent typing convenience

Parameters:

key - a lookup key to resolve the value within the context

Returns:

an Optional of the value for that key.

hasKey

boolean hasKey(Object key)

Return true if a particular key resolves to a value within the RequestContext.

Parameters:

key - a lookup key to test for

Returns:

true if this context contains the given key

isEmpty

boolean isEmpty()

Return true if the RequestContext is empty.

Returns:

true if the RequestContext is empty.

put

void put(Object key,
         Object value)

Modifies this instance with the given key and value. If that key existed in the current RequestContext, its associated value is replaced.

Parameters:

key - the key to add/update

value - the value to associate to the key

Throws:

NullPointerException - if either the key or value are null

putNonNull

default void putNonNull(Object key,
                        @Nullable
                        Object valueOrNull)

Modifies this instance with the given key and value only if the value is not null. If that key existed in the current Context, its associated value is replaced in the resulting RequestContext.

Parameters:

key - the key to add/update

valueOrNull - the value to associate to the key, null to ignore the operation

Throws:

NullPointerException - if the key is null

delete

void delete(Object key)

Delete the given key and its associated value from the RequestContext.

Parameters:

key - the key to remove.

size

int size()

Return the size of this RequestContext, the number of key/value pairs stored inside it.

Returns:

the size of the RequestContext

stream

Stream<Map.Entry<Object,Object>> stream()

Stream key/value pairs from this RequestContext

It is not specified whether modification of a Map.Entry instance in the Stream results in a modification of the state of the RequestContext, or whether the Map.Entry instances are modifiable. That is considered an implementation detail, so users of this method should not rely on the behavior one way or the other unless the implementing class has documented it.

Returns:

a Stream of key/value pairs held by this context