ReadPreference (mongo-java-driver 3.3.0-query-log-max-size API)

java.lang.Object
- com.mongodb.ReadPreference

直接已知子类:

TaggableReadPreference
```
@Immutable
public abstract class ReadPreference
extends java.lang.Object
```
A class that represents preferred replica set members to which a query or command can be sent.

MongoDB documentation

Read Preference

方法概要

所有方法静态方法实例方法抽象方法具体方法
限定符和类型	方法和说明
`abstract java.util.List<ServerDescription>`	`choose(ClusterDescription clusterDescription)` Chooses the servers from the given cluster than match this read preference.
`abstract java.lang.String`	`getName()` Gets the name of this read preference.
`abstract boolean`	`isSlaveOk()` True if this read preference allows reading from a secondary member of a replica set.
`static ReadPreference`	`nearest()` Gets a read preference that forces reads to a primary or a secondary.
`static TaggableReadPreference`	`nearest(java.util.List<TagSet> tagSetList)` Gets a read preference that forces reads to the primary or a secondary with one of the given sets of tags.
`static TaggableReadPreference`	`nearest(TagSet tagSet)` Gets a read preference that forces reads to the primary or a secondary with the given set of tags.
`static ReadPreference`	`primary()` Gets a read preference that forces read to the primary.
`static ReadPreference`	`primaryPreferred()` Gets a read preference that forces reads to the primary if available, otherwise to a secondary.
`static TaggableReadPreference`	`primaryPreferred(java.util.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.
`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.
`static ReadPreference`	`secondary()` Gets a read preference that forces reads to a secondary.
`static TaggableReadPreference`	`secondary(java.util.List<TagSet> tagSetList)` Gets a read preference that forces reads to a secondary with one of the given sets of tags.
`static TaggableReadPreference`	`secondary(TagSet tagSet)` Gets a read preference that forces reads to a secondary with the given set of tags.
`static ReadPreference`	`secondaryPreferred()` Gets a read preference that forces reads to a secondary if one is available, otherwise to the primary.
`static TaggableReadPreference`	`secondaryPreferred(java.util.List<TagSet> tagSetList)` Gets a read preference that forces reads to a secondary with one of the given sets of tags.
`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.
`abstract BsonDocument`	`toDocument()` Gets a document representing this read preference in the wire protocol.
`static ReadPreference`	`valueOf(java.lang.String name)` Creates a read preference from the given read preference name.
`static TaggableReadPreference`	`valueOf(java.lang.String name, java.util.List<TagSet> tagSetList)` Creates a taggable read preference from the given read preference name and list of tag sets.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 方法详细资料
  - isSlaveOk
```
public abstract boolean isSlaveOk()
```
    True if this read preference allows reading from a secondary member of a replica set.
    
    返回:
    
    if reading from a secondary is ok
  - getName
```
public abstract java.lang.String getName()
```
    Gets the name of this read preference.
    
    返回:
    
    the name
  - toDocument
```
public abstract BsonDocument toDocument()
```
    Gets a document representing this read preference in the wire protocol.
    
    返回:
    
    the document
  - choose
```
public abstract java.util.List<ServerDescription> choose(ClusterDescription clusterDescription)
```
    Chooses the servers from the given cluster than match this read preference.
    
    参数:
    
    clusterDescription - the cluster description
    
    返回:
    
    a list of matching server descriptions, which may be empty but may not be null
  - primary
```
public static ReadPreference primary()
```
    Gets a read preference that forces read to the primary.
    
    返回:
    
    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.
    
    返回:
    
    ReadPreference which reads primary if available.
  - secondary
```
public static ReadPreference secondary()
```
    Gets a read preference that forces reads to a secondary.
    
    返回:
    
    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.
    
    返回:
    
    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.
    
    返回:
    
    ReadPreference which reads nearest
  - 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.
    
    参数:
    
    tagSet - the set of tags to limit the list of secondaries to.
    
    返回:
    
    ReadPreference which reads primary if available, otherwise a secondary respective of tags.\
    
    从以下版本开始:
    
    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.
    
    参数:
    
    tagSet - the set of tags to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads secondary respective of tags.
    
    从以下版本开始:
    
    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.
    
    参数:
    
    tagSet - the set of tags to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
    
    从以下版本开始:
    
    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.
    
    参数:
    
    tagSet - the set of tags to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads nearest node respective of tags.
    
    从以下版本开始:
    
    2.13
  - primaryPreferred
```
public static TaggableReadPreference primaryPreferred(java.util.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.
    
    参数:
    
    tagSetList - the list of tag sets to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads primary if available, otherwise a secondary respective of tags.
    
    从以下版本开始:
    
    2.13
  - secondary
```
public static TaggableReadPreference secondary(java.util.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.
    
    参数:
    
    tagSetList - the list of tag sets to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads secondary respective of tags.
    
    从以下版本开始:
    
    2.13
  - secondaryPreferred
```
public static TaggableReadPreference secondaryPreferred(java.util.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.
    
    参数:
    
    tagSetList - the list of tag sets to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads secondary if available respective of tags, otherwise from primary irrespective of tags.
    
    从以下版本开始:
    
    2.13
  - nearest
```
public static TaggableReadPreference nearest(java.util.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.
    
    参数:
    
    tagSetList - the list of tag sets to limit the list of secondaries to
    
    返回:
    
    ReadPreference which reads nearest node respective of tags.
    
    从以下版本开始:
    
    2.13
  - valueOf
```
public static ReadPreference valueOf(java.lang.String name)
```
    Creates a read preference from the given read preference name.
    
    参数:
    
    name - the name of the read preference
    
    返回:
    
    the read preference
  - valueOf
```
public static TaggableReadPreference valueOf(java.lang.String name,
                                             java.util.List<TagSet> tagSetList)
```
    Creates a taggable read preference from the given read preference name and list of tag sets.
    
    参数:
    
    name - the name of the read preference
    
    tagSetList - the list of tag sets
    
    返回:
    
    the taggable read preference
    
    从以下版本开始:
    
    2.13

类 ReadPreference

方法概要

从类继承的方法 java.lang.Object

方法详细资料

isSlaveOk

getName

toDocument

choose

primary

primaryPreferred

secondary

secondaryPreferred

nearest

primaryPreferred

secondary

secondaryPreferred

nearest

primaryPreferred

secondary

secondaryPreferred

nearest

valueOf

valueOf