Package com.linecorp.armeria.common

Interface AttributesGetters

All Known Subinterfaces:

Attributes, ConcurrentAttributes

@UnstableApi
public interface AttributesGetters

Provides the getter methods to Attributes and ConcurrentAttributes.

Method Summary

Modifier and Type	Method	Description
<T> T	attr(AttributeKey<T> key)	Returns the value associated with the given AttributeKey or null if there's no value set by AttributesSetters.set(AttributeKey, Object).
Iterator<Map.Entry<AttributeKey<?>,Object>>	attrs()	Returns the Iterator of all Map.Entrys this AttributesGetters contains.
default boolean	hasAttr(AttributeKey<?> key)	Returns true if and only if the value associated with the specified AttributeKey is not null.
default boolean	hasOwnAttr(AttributeKey<?> key)	Returns true if and only if the value associated with the specified AttributeKey is not null.
boolean	isEmpty()	Returns true if this AttributesGetters does not contain any entries.
<T> T	ownAttr(AttributeKey<T> key)	Returns the value associated with the given AttributeKey or null if there's no value set by AttributesBuilder.set(AttributeKey, Object).
Iterator<Map.Entry<AttributeKey<?>,Object>>	ownAttrs()	Returns the Iterator of all Map.Entrys this AttributesGetters contains.
@Nullable AttributesGetters	parent()	Returns the parent() which was specified when creating this AttributesGetters.
int	size()	Returns the number of AttributeKey-value mappings in this AttributesGetters.

Method Details

attr

@Nullable
<T> T attr(AttributeKey<T> key)

Returns the value associated with the given AttributeKey or null if there's no value set by AttributesSetters.set(AttributeKey, Object). If there is no value in this AttributesGetters but it exists in parent(), the value in the parent()} will be returned.

See Also:

• ownAttr(AttributeKey)

ownAttr

@Nullable
<T> T ownAttr(AttributeKey<T> key)

Returns the value associated with the given AttributeKey or null if there's no value set by AttributesBuilder.set(AttributeKey, Object).

Unlike attr(AttributeKey), this does not search in parent().

See Also:

• attr(AttributeKey)

hasAttr

default boolean hasAttr(AttributeKey<?> key)

Returns true if and only if the value associated with the specified AttributeKey is not null.

See Also:

• hasOwnAttr(AttributeKey)

hasOwnAttr

default boolean hasOwnAttr(AttributeKey<?> key)

Returns true if and only if the value associated with the specified AttributeKey is not null.

Unlike hasAttr(AttributeKey), this does not search in parent().

See Also:

• hasAttr(AttributeKey)

ownAttrs

Iterator<Map.Entry<AttributeKey<?>,Object>> ownAttrs()

Returns the Iterator of all Map.Entrys this AttributesGetters contains.

Unlike attrs(), this does not iterate parent()}.

For example:

 static final AttributeKey<String> USER_ID = AttributeKey.valueOf("USER_ID");
 static final AttributeKey<String> SECRET_TOKEN = AttributeKey.valueOf("SECRET_TOKEN");
 static final AttributeKey<String> TRACE_ID = AttributeKey.valueOf("TRACE_ID");

 Attributes parent = Attributes.of(USER_ID, "Meri Kim",
                                   SECRET_TOKEN, "secret-1");

 Attributes child = Attributes.builder(parent)
                              .set(SECRET_TOKEN, "secret-2")
                              .set(TRACE_ID, "trace-1")
                              .build();

 Iterator<Entry<AttributeKey<?>, Object>> attrs = child.ownAttrs();
 assert Iterables.size(attrs) == 2;
 assert Streams.stream(child.attrs())
               .map(Entry::getValue)
               .sorted()
               .collect(Collectors.toList())
               .equals(List.of("secret-2", "trace-1"));
 

See Also:

• attrs()

attrs

Iterator<Map.Entry<AttributeKey<?>,Object>> attrs()

Returns the Iterator of all Map.Entrys this AttributesGetters contains.

The Iterator returned by this method will also yield the Map.Entrys from the parent()} except those whose AttributeKey exist already in this context. For example:

 static final AttributeKey<String> USER_ID = AttributeKey.valueOf("USER_ID");
 static final AttributeKey<String> SECRET_TOKEN = AttributeKey.valueOf("SECRET_TOKEN");
 static final AttributeKey<String> TRACE_ID = AttributeKey.valueOf("TRACE_ID");

 Attributes parent = Attributes.of(USER_ID, "Meri Kim",
                                   SECRET_TOKEN, "secret-1");

 Attributes child = Attributes.builder(parent)
                              .set(SECRET_TOKEN, "secret-2")
                              .set(TRACE_ID, "trace-1")
                              .build();

 Iterator<Entry<AttributeKey<?>, Object>> attrs = child.attrs();
 assert Iterables.size(attrs) == 3;
 assert Streams.stream(child.attrs())
               .map(Entry::getValue)
               .sorted()
               .collect(Collectors.toList())
               // "secret-1" is overridden by "secret-2"
               .equals(List.of("Meri Kim", "secret-2", "trace-1"));
 

parent

@Nullable
@Nullable AttributesGetters parent()

Returns the parent() which was specified when creating this AttributesGetters.

See Also:

• Attributes.fromParent(AttributesGetters)
• Attributes.builder(AttributesGetters)
• ConcurrentAttributes.fromParent(AttributesGetters)

isEmpty

boolean isEmpty()

Returns true if this AttributesGetters does not contain any entries.

size

int size()

Returns the number of AttributeKey-value mappings in this AttributesGetters.

If the same AttributeKey is both in the parent() and the child Attributes, only the AttributeKey-value mapping in the child will be counted.

 static final AttributeKey<String> USER_ID = AttributeKey.valueOf("USER_ID");
 static final AttributeKey<String> SECRET_TOKEN = AttributeKey.valueOf("SECRET_TOKEN");
 static final AttributeKey<String> TRACE_ID = AttributeKey.valueOf("TRACE_ID");

 Attributes parent = Attributes.of(USER_ID, "Meri Kim",
                                   SECRET_TOKEN, "secret-1");
 assert parent.size() == 2;

 Attributes child = Attributes.builder(parent)
                              .set(SECRET_TOKEN, "secret-2")
                              .set(TRACE_ID, "trace-1")
                              .build();
 assert child.size() == 3;