Package com.mongodb

Class ReadPreference

java.lang.Object
com.mongodb.ReadPreference
Direct Known Subclasses:
TaggableReadPreference
@Immutable public abstract class ReadPreference extends Object
A class that represents preferred replica set members to which a query or command can be sent.
MongoDB documentation
Read Preference

  • Method Details

    • withTagSet

      public abstract ReadPreference withTagSet(TagSet tagSet)
      Create a new ReadPreference instance with a new tag set.

      Note: this method is not supported for a primary read preference.

      Parameters:
      tagSet - the new tag set
      Returns:
      a new ReadPreference instance with a new tag set
      Since:
      4.1

    • withTagSetList

      public abstract ReadPreference withTagSetList(List<TagSet> tagSet)
      Create a new ReadPreference instance with a new tag set list.

      Note: this method is not supported for a primary read preference.

      Parameters:
      tagSet - the new tag set list
      Returns:
      a new ReadPreference instance with a new tag set list
      Since:
      4.1

    • withMaxStalenessMS

      public abstract ReadPreference withMaxStalenessMS(Long maxStalenessMS, TimeUnit timeUnit)
      Create a new ReadPreference instance with the maximum acceptable staleness of a secondary in order to be considered for read operations.

      Note: this method is not supported for a primary read preference.

      Parameters:
      maxStalenessMS - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      a new ReadPreference instance with a new maximum allowable staleness
      Since:
      4.1
      Since server release
      3.4

    • withHedgeOptions

      public abstract ReadPreference withHedgeOptions(ReadPreferenceHedgeOptions hedgeOptions)
      Create a new ReadPreference instance with hedge options.

      Note: this method is not supported for a primary read preference.

      Parameters:
      hedgeOptions - the hedge options
      Returns:
      a new ReadPreference instance with hedge options
      Since:
      4.1
      Since server release
      4.4

    • isSlaveOk

      @Deprecated public abstract boolean isSlaveOk()
      Deprecated.
      Prefer isSecondaryOk()
      True if this read preference allows reading from a secondary member of a replica set.
      Returns:
      if reading from a secondary is ok

    • isSecondaryOk

      public abstract boolean isSecondaryOk()
      True if this read preference allows reading from a secondary member of a replica set.
      Returns:
      if reading from a secondary is ok
      Since:
      4.4

    • getName

      public abstract String getName()
      Gets the name of this read preference.
      Returns:
      the name

    • toDocument

      public abstract BsonDocument toDocument()
      Gets a document representing this read preference in the wire protocol.
      Returns:
      the document

    • choose

      public final List<ServerDescription> choose(ClusterDescription clusterDescription)
      Chooses the servers from the given cluster than match this read preference.
      Parameters:
      clusterDescription - the cluster description
      Returns:
      a list of matching server descriptions, which may be empty but may not be null

    • chooseForNonReplicaSet

      protected abstract List<ServerDescription> chooseForNonReplicaSet(ClusterDescription clusterDescription)
      Choose for non-replica sets.
      Parameters:
      clusterDescription - the cluster description
      Returns:
      the list of matching server descriptions

    • chooseForReplicaSet

      protected abstract List<ServerDescription> chooseForReplicaSet(ClusterDescription clusterDescription)
      Choose for replica sets.
      Parameters:
      clusterDescription - the cluster description
      Returns:
      the list of matching server descriptions

    • primary

      public static ReadPreference primary()
      Gets a read preference that forces read to the primary.
      Returns:
      ReadPreference which reads from primary only

    • primaryPreferred

      public static ReadPreference primaryPreferred()
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary.
      Returns:
      ReadPreference which reads primary if available.

    • secondary

      public static ReadPreference secondary()
      Gets a read preference that forces reads to a secondary.
      Returns:
      ReadPreference which reads secondary.

    • secondaryPreferred

      public static ReadPreference secondaryPreferred()
      Gets a read preference that forces reads to a secondary if one is available, otherwise to the primary.
      Returns:
      ReadPreference which reads secondary if available, otherwise from primary.

    • nearest

      public static ReadPreference nearest()
      Gets a read preference that forces reads to a primary or a secondary.
      Returns:
      ReadPreference which reads nearest

    • primaryPreferred

      public static ReadPreference primaryPreferred(long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary.
      Parameters:
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads primary if available.
      Since:
      3.4
      See Also:

    • secondary

      public static ReadPreference secondary(long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary that is less stale than the given maximum.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary.
      Since:
      3.4
      See Also:

    • secondaryPreferred

      public static ReadPreference secondaryPreferred(long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary that is less stale than the given maximumm if one is available, otherwise to the primary.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      *
      Parameters:
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary if available, otherwise from primary.
      Since:
      3.4
      See Also:

    • nearest

      public static ReadPreference nearest(long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a primary or a secondary that is less stale than the given maximum.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads nearest
      Since:
      3.4
      See Also:

    • primaryPreferred

      public static TaggableReadPreference primaryPreferred(TagSet tagSet)
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary with the given set of tags.
      Parameters:
      tagSet - the set of tags to limit the list of secondaries to.
      Returns:
      ReadPreference which reads primary if available, otherwise a secondary respective of tags.\
      Since:
      2.13

    • secondary

      public static TaggableReadPreference secondary(TagSet tagSet)
      Gets a read preference that forces reads to a secondary with the given set of tags.
      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      Returns:
      ReadPreference which reads secondary respective of tags.
      Since:
      2.13

    • secondaryPreferred

      public static TaggableReadPreference secondaryPreferred(TagSet tagSet)
      Gets a read preference that forces reads to a secondary with the given set of tags, or the primary is none are available.
      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      Returns:
      ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
      Since:
      2.13

    • nearest

      public static TaggableReadPreference nearest(TagSet tagSet)
      Gets a read preference that forces reads to the primary or a secondary with the given set of tags.
      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      Returns:
      ReadPreference which reads nearest node respective of tags.
      Since:
      2.13

    • primaryPreferred

      public static TaggableReadPreference primaryPreferred(TagSet tagSet, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary with the given set of tags that is less stale than the given maximum.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSet - the set of tags to limit the list of secondaries to.
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads primary if available, otherwise a secondary respective of tags.\
      Since:
      3.4
      See Also:

    • secondary

      public static TaggableReadPreference secondary(TagSet tagSet, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary with the given set of tags that is less stale than the given maximum.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary respective of tags.
      Since:
      3.4
      See Also:

    • secondaryPreferred

      public static TaggableReadPreference secondaryPreferred(TagSet tagSet, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary with the given set of tags that is less stale than the given maximum, or the primary is none are available.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      *
      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
      Since:
      3.4
      See Also:

    • nearest

      public static TaggableReadPreference nearest(TagSet tagSet, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to the primary or a secondary with the given set of tags that is less stale than the given maximum.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSet - the set of tags to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads nearest node respective of tags.
      Since:
      3.4
      See Also:

    • primaryPreferred

      public static TaggableReadPreference primaryPreferred(List<TagSet> tagSetList)
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary with one of the given sets of tags. The driver will look for a secondary with each tag set in the given list, stopping after one is found, or failing if no secondary can be found that matches any of the tag sets in the list.
      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      Returns:
      ReadPreference which reads primary if available, otherwise a secondary respective of tags.
      Since:
      2.13

    • secondary

      public static TaggableReadPreference secondary(List<TagSet> tagSetList)
      Gets a read preference that forces reads to a secondary with one of the given sets of tags. The driver will look for a secondary with each tag set in the given list, stopping after one is found, or failing if no secondary can be found that matches any of the tag sets in the list.
      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      Returns:
      ReadPreference which reads secondary respective of tags.
      Since:
      2.13

    • secondaryPreferred

      public static TaggableReadPreference secondaryPreferred(List<TagSet> tagSetList)
      Gets a read preference that forces reads to a secondary with one of the given sets of tags. The driver will look for a secondary with each tag set in the given list, stopping after one is found, or the primary if none are available.
      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      Returns:
      ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
      Since:
      2.13

    • nearest

      public static TaggableReadPreference nearest(List<TagSet> tagSetList)
      Gets a read preference that forces reads to the primary or a secondary with one of the given sets of tags. The driver will look for a secondary with each tag set in the given list, stopping after one is found, or the primary if none are available.
      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      Returns:
      ReadPreference which reads nearest node respective of tags.
      Since:
      2.13

    • primaryPreferred

      public static TaggableReadPreference primaryPreferred(List<TagSet> tagSetList, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to the primary if available, otherwise to a secondary with one of the given sets of tags that is less stale than the given maximum.

      The driver will look for a secondary with each tag set in the given list, stopping after one is found, or failing if no secondary can be found that matches any of the tag sets in the list.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads primary if available, otherwise a secondary respective of tags.
      Since:
      3.4
      See Also:

    • secondary

      public static TaggableReadPreference secondary(List<TagSet> tagSetList, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary with one of the given sets of tags that is less stale than the given maximum.

      The driver will look for a secondary with each tag set in the given list, stopping after one is found, or failing if no secondary can be found that matches any of the tag sets in the list.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary respective of tags.
      Since:
      3.4
      See Also:

    • secondaryPreferred

      public static TaggableReadPreference secondaryPreferred(List<TagSet> tagSetList, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to a secondary with one of the given sets of tags that is less stale than the given maximum.

      The driver will look for a secondary with each tag set in the given list, stopping after one is found, or the primary if none are available.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
      Since:
      3.4
      See Also:

    • nearest

      public static TaggableReadPreference nearest(List<TagSet> tagSetList, long maxStaleness, TimeUnit timeUnit)
      Gets a read preference that forces reads to the primary or a secondary with one of the given sets of tags that is less stale than the given maximum.

      The driver will look for a secondary with each tag set in the given list, stopping after one is found, or the primary if none are available.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      tagSetList - the list of tag sets to limit the list of secondaries to
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      ReadPreference which reads nearest node respective of tags.
      Since:
      3.4
      See Also:

    • valueOf

      public static ReadPreference valueOf(String name)
      Creates a read preference from the given read preference name.
      Parameters:
      name - the name of the read preference
      Returns:
      the read preference

    • valueOf

      public static TaggableReadPreference valueOf(String name, List<TagSet> tagSetList)
      Creates a taggable read preference from the given read preference name and list of tag sets.
      Parameters:
      name - the name of the read preference
      tagSetList - the list of tag sets
      Returns:
      the taggable read preference
      Since:
      2.13

    • valueOf

      public static TaggableReadPreference valueOf(String name, List<TagSet> tagSetList, long maxStaleness, TimeUnit timeUnit)
      Creates a taggable read preference from the given read preference name, list of tag sets, and max allowable staleness of secondaries.

      The driver estimates the staleness of each secondary, based on lastWriteDate values provided in server hello responses, and selects only those secondaries whose staleness is less than or equal to maxStaleness.

      Parameters:
      name - the name of the read preference
      tagSetList - the list of tag sets
      maxStaleness - the max allowable staleness of secondaries. The minimum value is either 90 seconds, or the heartbeat frequency plus 10 seconds, whichever is greatest.
      timeUnit - the time unit of maxStaleness
      Returns:
      the taggable read preference
      Since:
      3.4
      See Also: