Dictionary API reference for Momento Cache

This page details the Momento API methods for the dictionary collection data type.

Dictionary methods

DictionaryFetch

Gets a dictionary item from a cache.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	The name of the dictionary item to be retreived.

Method response object

The response object for DictionaryFetch returns three possible options, a cache hit, miss, or an error.

• Cache hit
  • valueDictionaryBytesBytes(): Map<Bytes, Bytes>
  • valueDictionaryStringString(): Map<String, String>
  • valueDictionaryStringBytes(): Map<String, Bytes>
  • valueDictionaryBytesString(): Map<Bytes, String>
  • toString(): string - displays the field/value pairs, truncated.
• Cache miss
• Cache error

See response objects for specific information.

DictionaryGetField

Get one field from a dictionary item in the cache.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be retreived.
field	String/bytes	Name of the field in the dictionary item to be retreived.

Method response object

• Cache hit

  • fieldString(): string

  • fieldBytes(): bytes

  • valueString(): string

  • valueBytes(): bytes

    These return the field and its value from the dictionary.

• Cache miss

  • fieldString(): string
  • fieldBytes(): bytes

• Cache error

  • fieldString(): string
  • fieldBytes(): bytes

See response objects for specific information.

DictionaryGetFields

Get one or more fields from a dictionary in the cache.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be retreived.
fields	String[]/bytes[]	Name of the field in the dictionary item to be retreived.

Method response object

• Cache hit
  • valueDictionaryBytesBytes(): Map<Bytes, Bytes>
  • valueDictionaryStringString(): Map<String, String>
  • valueDictionaryStringBytes(): Map<String, Bytes>
  • valueDictionaryBytesString(): Map<Bytes, String>
  • toString(): string - displays truncated valueDictionaryStringString()
• Cache miss
• Error

See response objects for specific information.

DictionaryIncrement

Adds to the value of a field, if and only if the existing value is a UTF-8 string representing a base 10 integer. If the field is missing from the dictionary, this method sets the field's value to the amount to increment by.

注記

The resulting incremented value must be between -9223372036854775808 and 9223372036854775807, ie. a signed 64-bit integer. If not, there will be an error response.

Examples:

• When the field does not exist, dictionaryIncrement(cache, dict, field, 10) will set the field's value to 10.
• When the field = 5, dictionaryIncrement(cache, dict, field, 10) will set the field's value to 15.
• When the field = ‘five’, it will respond with a FailedPreconditionException error.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be retreived.
field	String	bytes
amount	Integer	The quantity to add to the value. May be positive, negative, or zero. Defaults to 1.
ttl	CollectionTTL object	This will come back as a TTL construct.

Method response object

• Success
  • value(): integer - the new value after incrementing
  • toString(): string - displays the value()
• Error

See response objects for specific information.

DictionaryRemoveField

Removes a field from a dictionary item.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be retreived.
field	String	bytes

Method response object

• Success
• Error

See response objects for specific information.

DictionaryRemoveFields

Removes multiple fields from a dictionary item.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be retreived.
fields	String[]/bytes[]	Name of the field in the dictionary item to be retreived.

Method response object

• Success
• Error

See response objects for specific information.

DictionarySetField

Sets a field:value pair in an existing dictionary item. If the dictionary item does not exist, it is created with the new field:value pair.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be set.
field	String/bytes	Name of the field in the dictionary item to be set.
value	String/bytes	Value for the field to be set.
ttl	CollectionTTL object	TTL for the dictionary item in cache. This TTL takes precedence over the TTL used when initializing a cache client.

Method response object

• Success
• Error

See response objects for specific information.

DictionarySetFields

Sets several field:value pairs in a dictionary item. If the dictionary item does not exist, it is created with the new fields.

Name	Type	Description
cacheName	String	Name of the cache.
dictionaryName	String	Name of the dictionary item to be set.
fields	String[]/bytes[]	Field:value pair to be added to the dictionary item by the set operation.
ttl	CollectionTTL object	TTL for the dictionary item in cache. This TTL takes precedence over the TTL used when initializing a cache client.

Method response object

• Success
• Error

See response objects for specific information.