java.lang.Object
- java.lang.Enum<IsolationLevels>
- - org.eclipse.rdf4j.common.transaction.IsolationLevels

All Implemented Interfaces:

Serializable, Comparable<IsolationLevels>, IsolationLevel, TransactionSetting
```
public enum IsolationLevels
extends Enum<IsolationLevels>
implements IsolationLevel
```
Enumeration of Transaction IsolationLevels supported by RDF4J. Note that RDF4J stores are not required to support all levels, consult the documentatation for the specific SAIL implementation you are using to find out which levels are supported.

Author:

Jeen Broekstra, James Leigh

Enum Constant Summary

Enum Constants
Enum Constant	Description
`NONE`	None: the lowest isolation level; transactions can see their own changes, but may not be able to roll them back and no support for isolation among transactions is guaranteed
`READ_COMMITTED`	Read Committed: in this isolation level only statements from other transactions that have been committed (at some point) can be seen by this transaction.
`READ_UNCOMMITTED`	Read Uncommitted: transactions can be rolled back, but not necessarily isolated: concurrent transactions might see each other's uncommitted data (so-called 'dirty reads')
`SERIALIZABLE`	Serializable: in addition to `SNAPSHOT`, this isolation level requires that all other successful transactions must appear to occur either completely before or completely after a successful serializable transaction.
`SNAPSHOT`	Snapshot: in addition to `SNAPSHOT_READ`, successful transactions in this isolation level will operate against a particular dataset snapshot.
`SNAPSHOT_READ`	Snapshot Read: in addition to `READ_COMMITTED`, query results in this isolation level that are observed within a successful transaction will observe a consistent snapshot.

Field Summary
- Fields inherited from interface org.eclipse.rdf4j.common.transaction.IsolationLevel
  NAME

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static IsolationLevel`	`getCompatibleIsolationLevel(IsolationLevel level, List<? extends IsolationLevel> supportedLevels)`	Determines the first compatible isolation level in the list of supported levels, for the given level.
`boolean`	`isCompatibleWith(IsolationLevel otherLevel)`	Verifies if this transaction isolation level is compatible with the supplied other isolation level - that is, if this transaction isolation level offers at least the same guarantees as the other level.
`static IsolationLevels`	`valueOf(String name)`	Returns the enum constant of this type with the specified name.
`static IsolationLevels[]`	`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

Methods inherited from interface org.eclipse.rdf4j.common.transaction.IsolationLevel
getName, getValue

- Enum Constant Detail
  - NONE
```
public static final IsolationLevels NONE
```
    None: the lowest isolation level; transactions can see their own changes, but may not be able to roll them back and no support for isolation among transactions is guaranteed
  - READ_UNCOMMITTED
```
public static final IsolationLevels READ_UNCOMMITTED
```
    Read Uncommitted: transactions can be rolled back, but not necessarily isolated: concurrent transactions might see each other's uncommitted data (so-called 'dirty reads')
  - READ_COMMITTED
```
public static final IsolationLevels READ_COMMITTED
```
    Read Committed: in this isolation level only statements from other transactions that have been committed (at some point) can be seen by this transaction.
  - SNAPSHOT_READ
```
public static final IsolationLevels SNAPSHOT_READ
```
    Snapshot Read: in addition to READ_COMMITTED, query results in this isolation level that are observed within a successful transaction will observe a consistent snapshot. Changes to the data occurring while a query is evaluated will not affect that query result.
  - SNAPSHOT
```
public static final IsolationLevels SNAPSHOT
```
    Snapshot: in addition to SNAPSHOT_READ, successful transactions in this isolation level will operate against a particular dataset snapshot. Transactions in this isolation level will see either the complete effects of other transactions (consistently throughout) or not at all.
  - SERIALIZABLE
```
public static final IsolationLevels SERIALIZABLE
```
    Serializable: in addition to SNAPSHOT, this isolation level requires that all other successful transactions must appear to occur either completely before or completely after a successful serializable transaction.
- Method Detail
  - values
```
public static IsolationLevels[] 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 (IsolationLevels c : IsolationLevels.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static IsolationLevels 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
  - isCompatibleWith
```
public boolean isCompatibleWith(IsolationLevel otherLevel)
```
    Description copied from interface: IsolationLevel
    
    Verifies if this transaction isolation level is compatible with the supplied other isolation level - that is, if this transaction isolation level offers at least the same guarantees as the other level. By definition, every transaction isolation level is compatible with itself.
    
    Specified by:
    
    isCompatibleWith in interface IsolationLevel
    
    Parameters:
    
    otherLevel - an other isolation level to check compatibility against.
    
    Returns:
    
    true iff this isolation level is compatible with the supplied other isolation level, false otherwise.
  - getCompatibleIsolationLevel
```
public static IsolationLevel getCompatibleIsolationLevel(IsolationLevel level,
                                                         List<? extends IsolationLevel> supportedLevels)
```
    Determines the first compatible isolation level in the list of supported levels, for the given level. Returns the level itself if it is in the list of supported levels. Returns null if no compatible level can be found.
    
    Parameters:
    
    level - the IsolationLevel for which to determine a compatible level.
    
    supportedLevels - a list of supported isolation levels from which to select the closest compatible level.
    
    Returns:
    
    the given level if it occurs in the list of supported levels. Otherwise, the first compatible level in the list of supported isolation levels, or null if no compatible level can be found.
    
    Throws:
    
    IllegalArgumentException - if either one of the input parameters is null.

Enum IsolationLevels

Enum Constant Summary

Field Summary

Fields inherited from interface org.eclipse.rdf4j.common.transaction.IsolationLevel

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Methods inherited from interface org.eclipse.rdf4j.common.transaction.IsolationLevel

Enum Constant Detail

NONE

READ_UNCOMMITTED

READ_COMMITTED

SNAPSHOT_READ

SNAPSHOT

SERIALIZABLE

Method Detail

values

valueOf

isCompatibleWith

getCompatibleIsolationLevel