org.janusgraph.core.schema

Enum ConsistencyModifier

java.lang.Object

java.lang.Enum<ConsistencyModifier>

org.janusgraph.core.schema.ConsistencyModifier

All Implemented Interfaces:

Serializable, Comparable<ConsistencyModifier>

public enum ConsistencyModifier
extends Enum<ConsistencyModifier>

Used to control JanusGraph's consistency behavior on eventually consistent or other non-transactional backend systems. The consistency behavior can be defined for individual JanusGraphSchemaElements which then applies to all instances.

Consistency modifiers are installed on schema elements via JanusGraphManagement.setConsistency(JanusGraphSchemaElement, ConsistencyModifier) and can be read using JanusGraphManagement.getConsistency(JanusGraphSchemaElement).

Author:

Matthias Broecheler ([email protected])

Enum Constant Summary

Enum Constants

Enum Constant and Description
DEFAULT Uses the default consistency model guaranteed by the enclosing transaction against the configured storage backend.
FORK Causes JanusGraph to delete and add a new edge/property instead of overwriting an existing one, hence avoiding potential concurrent write conflicts.
LOCK Locks will be explicitly acquired to guarantee consistency if the storage backend supports locks.

Method Summary

Modifier and Type	Method and Description
static ConsistencyModifier	valueOf(String name) Returns the enum constant of this type with the specified name.
static ConsistencyModifier[]	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

DEFAULT

public static final ConsistencyModifier DEFAULT

Uses the default consistency model guaranteed by the enclosing transaction against the configured storage backend.

What this means exactly, depends on the configuration of the storage backend as well as the (optional) configuration of the enclosing transaction.

LOCK

public static final ConsistencyModifier LOCK

Locks will be explicitly acquired to guarantee consistency if the storage backend supports locks.

The exact consistency guarantees depend on the configured lock implementation.

Note, that locking may be ignored under certain transaction configurations.

FORK

public static final ConsistencyModifier FORK

Causes JanusGraph to delete and add a new edge/property instead of overwriting an existing one, hence avoiding potential concurrent write conflicts. This only applies to multi-edges and list-properties.

Note, that this potentially impacts how the data should be read.

Method Detail

values

public static ConsistencyModifier[] 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 (ConsistencyModifier c : ConsistencyModifier.values())
    System.out.println(c);

Returns:

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

valueOf

public static ConsistencyModifier 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