org.apache.zookeeper

Class Op

java.lang.Object

org.apache.zookeeper.Op

Direct Known Subclasses:

Op.Check, Op.Create, Op.Delete, Op.GetChildren, Op.GetData, Op.SetData

public abstract class Op
extends Object

Represents a single operation in a multi-operation transaction. Each operation can be a create, update, delete, a version check or just read operations like getChildren or getData. Sub-classes of Op each represent each detailed type but should not normally be referenced except via the provided factory methods.

See Also:

ZooKeeper.create(String, byte[], java.util.List, CreateMode), ZooKeeper.create(String, byte[], java.util.List, CreateMode, org.apache.zookeeper.AsyncCallback.StringCallback, Object), ZooKeeper.delete(String, int), ZooKeeper.setData(String, byte[], int), ZooKeeper.getData(String, boolean, Stat), ZooKeeper.getChildren(String, boolean)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Op.Check
static class	Op.Create
static class	Op.CreateTTL
static class	Op.Delete
static class	Op.GetChildren
static class	Op.GetData
static class	Op.OpKind
static class	Op.SetData

Method Summary

Modifier and Type	Method and Description
static Op	check(String path, int version) Constructs an version check operation.
static Op	create(String path, byte[] data, List<ACL> acl, CreateMode createMode) Constructs a create operation.
static Op	create(String path, byte[] data, List<ACL> acl, CreateMode createMode, long ttl) Constructs a create operation.
static Op	create(String path, byte[] data, List<ACL> acl, int flags) Constructs a create operation.
static Op	create(String path, byte[] data, List<ACL> acl, int flags, long ttl) Constructs a create operation.
static Op	delete(String path, int version) Constructs a delete operation.
static Op	getChildren(String path)
static Op	getData(String path)
Op.OpKind	getKind() Gets the kind of an Op.
String	getPath() Gets the path for an Op.
int	getType() Gets the integer type code for an Op.
static Op	setData(String path, byte[] data, int version) Constructs an update operation.
abstract Record	toRequestRecord() Encodes an op for wire transmission.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

create

public static Op create(String path,
                        byte[] data,
                        List<ACL> acl,
                        int flags)

Constructs a create operation. Arguments are as for the ZooKeeper method of the same name.

Parameters:

path - the path for the node

data - the initial data for the node

acl - the acl for the node

flags - specifying whether the node to be created is ephemeral and/or sequential but using the integer encoding.

See Also:

ZooKeeper.create(String, byte[], java.util.List, CreateMode), CreateMode.fromFlag(int)

create

public static Op create(String path,
                        byte[] data,
                        List<ACL> acl,
                        int flags,
                        long ttl)

Constructs a create operation. Arguments are as for the ZooKeeper method of the same name but adding an optional ttl

Parameters:

path - the path for the node

data - the initial data for the node

acl - the acl for the node

flags - specifying whether the node to be created is ephemeral and/or sequential but using the integer encoding.

ttl - optional ttl or 0 (flags must imply a TTL creation mode)

See Also:

ZooKeeper.create(String, byte[], java.util.List, CreateMode), CreateMode.fromFlag(int)

create

public static Op create(String path,
                        byte[] data,
                        List<ACL> acl,
                        CreateMode createMode)

Constructs a create operation. Arguments are as for the ZooKeeper method of the same name.

Parameters:

path - the path for the node

data - the initial data for the node

acl - the acl for the node

createMode - specifying whether the node to be created is ephemeral and/or sequential

See Also:

ZooKeeper.create(String, byte[], java.util.List, CreateMode)

create

public static Op create(String path,
                        byte[] data,
                        List<ACL> acl,
                        CreateMode createMode,
                        long ttl)

Constructs a create operation. Arguments are as for the ZooKeeper method of the same name but adding an optional ttl

Parameters:

path - the path for the node

data - the initial data for the node

acl - the acl for the node

createMode - specifying whether the node to be created is ephemeral and/or sequential

ttl - optional ttl or 0 (createMode must imply a TTL)

See Also:

ZooKeeper.create(String, byte[], java.util.List, CreateMode)

delete

public static Op delete(String path,
                        int version)

Constructs a delete operation. Arguments are as for the ZooKeeper method of the same name.

Parameters:

path - the path of the node to be deleted.

version - the expected node version.

See Also:

ZooKeeper.delete(String, int)

setData

public static Op setData(String path,
                         byte[] data,
                         int version)

Constructs an update operation. Arguments are as for the ZooKeeper method of the same name.

Parameters:

path - the path of the node

data - the data to set

version - the expected matching version

See Also:

ZooKeeper.setData(String, byte[], int)

check

public static Op check(String path,
                       int version)

Constructs an version check operation. Arguments are as for the ZooKeeper.setData method except that no data is provided since no update is intended. The purpose for this is to allow read-modify-write operations that apply to multiple znodes, but where some of the znodes are involved only in the read, not the write. A similar effect could be achieved by writing the same data back, but that leads to way more version updates than are necessary and more writing in general.

Parameters:

path - the path of the node

version - the expected matching version

getChildren

public static Op getChildren(String path)

getData

public static Op getData(String path)

getType

public int getType()

Gets the integer type code for an Op. This code should be as from ZooDefs.OpCode

Returns:

The type code.

See Also:

ZooDefs.OpCode

getPath

public String getPath()

Gets the path for an Op.

Returns:

The path.

getKind

public Op.OpKind getKind()

Gets the kind of an Op.

Returns:

The OpKind value.

toRequestRecord

public abstract Record toRequestRecord()

Encodes an op for wire transmission.

Returns:

An appropriate Record structure.