com.allanbank.mongodb

Enum ReadPreference.Mode

java.lang.Object

java.lang.Enum<ReadPreference.Mode>

com.allanbank.mongodb.ReadPreference.Mode

All Implemented Interfaces:

Serializable, Comparable<ReadPreference.Mode>

Enclosing class:

ReadPreference

public static enum ReadPreference.Mode
extends Enum<ReadPreference.Mode>

Enumeration of the basic ReadPreference modes of service.

Copyright ©:

2012-2013, Allanbank Consulting, Inc., All Rights Reserved

Enum Constant Summary

Enum Constants

Enum Constant and Description
NEAREST Use the nearest (by latency measurement) member of the replica set: either primary or secondary servers are allowed.
PRIMARY_ONLY Reads should only be attempted from the primary member of the replica set.
PRIMARY_PREFERRED Read from the primary but in the case of a fault may fallback to a secondary.
SECONDARY_ONLY Do not attempt to read from the primary.
SECONDARY_PREFERRED Try to first read from a secondary.
SERVER Do not attempt to read from any server other than the one specified.

Method Summary

Methods

Modifier and Type	Method and Description
String	getToken() Returns the token passed to the mongos server when in a shared environment.
boolean	isSecondaryOk() Returns true if the mode allows reading from secondaries, false otherwise.
static ReadPreference.Mode	valueOf(String name) Returns the enum constant of this type with the specified name.
static ReadPreference.Mode[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

NEAREST

public static final ReadPreference.Mode NEAREST

Use the nearest (by latency measurement) member of the replica set: either primary or secondary servers are allowed.

If tag matching documents are specified then only server matching the specified tag matching documents would be used.

PRIMARY_ONLY

public static final ReadPreference.Mode PRIMARY_ONLY

Reads should only be attempted from the primary member of the replica set.

PRIMARY_PREFERRED

public static final ReadPreference.Mode PRIMARY_PREFERRED

Read from the primary but in the case of a fault may fallback to a secondary.

If tag matching documents are specified and a fallback to a secondary is required then only secondaries matching the specified tag matching documents would be used.

SECONDARY_ONLY

public static final ReadPreference.Mode SECONDARY_ONLY

Do not attempt to read from the primary.

If tag matching documents are specified then only secondaries matching the specified tag matching documents would be used.

SECONDARY_PREFERRED

public static final ReadPreference.Mode SECONDARY_PREFERRED

Try to first read from a secondary. If none are available "fallback" to the primary.

If tag matching documents are specified then only secondaries matching the specified tag matching documents would be used.

SERVER

public static final ReadPreference.Mode SERVER

Do not attempt to read from any server other than the one specified. Used by the MongoIterator to ensure cursor fetch and terminate requests use the originating server.

Method Detail

values

public static ReadPreference.Mode[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (ReadPreference.Mode c : ReadPreference.Mode.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ReadPreference.Mode valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

getToken

public String getToken()

Returns the token passed to the mongos server when in a shared environment.

Returns:

The token passed to the mongos server when in a shared environment.

isSecondaryOk

public boolean isSecondaryOk()

Returns true if the mode allows reading from secondaries, false otherwise.

Returns:

True if the mode allows reading from secondaries, false otherwise.