org.zkoss.zk.au
Class Command

java.lang.Object
  org.zkoss.zk.au.Command

Direct Known Subclasses:

BookmarkChangedCommand, CheckCommand, ClientInfoCommand, ColSizeCommand, ComponentCommand, DropCommand, DummyCommand, EchoCommand, ErrorCommand, GenericCommand, GetUploadInfoCommand, InnerWidthCommand, InputCommand, KeyCommand, MinMaximizeCommand, MouseCommand, MoveCommand, OpenCommand, PageSizeCommand, PagingCommand, PortalMoveCommand, RedrawCommand, RemoveCommand, RemoveDesktopCommand, RenderCommand, ScrollCommand, SelectCommand, SelectionCommand, SizeCommand, TimerCommand, UpdateResultCommand, URIChangedCommand, ZIndexCommand

public abstract class Command
extends java.lang.Object

Represents a command of a request (AuRequest). Each command is unique no matter getId() is the same or not.

There are two kind of commands: global commands and component-specific commands. A global command is stored in a global map (as soon as it is instantiated), and it can be retrieved by invoking AuRequest.getCommand(String).

A component-specific command is maintained by a component, and can be retrieved by use of ComponentCtrl.getCommand(java.lang.String).

A global command is extended from Command. Since it is global, you have to instantiate an instance at startup. A typical usage is to declare a static instance of a class.

A component-specific command is extended from ComponentCommand. It is not part of the global map, and it is used only if it is returned by ComponentCtrl.getCommand(java.lang.String).

Author:

tomyeh

Field Summary

static int	CTRL_GROUP Whether this command belongs to the control group.
static int	IGNORABLE Whether this command is ignorable.
static int	IGNORE_IMMEDIATE_OLD_EQUIV Whether to drop the existent command (in the queue) if it is the same as the immediate following one.
static int	IGNORE_OLD_EQUIV Whether to drop the existent command (in the queue) if it is the same as the new arrival one.
static int	SKIP_IF_EVER_ERROR Whether to skip this command if previous commands ever caused errors.

Constructor Summary

protected

Command(java.lang.String id, int flags) Construct a command.

Method Summary

boolean	equals(java.lang.Object o)
int	getFlags() Returns the attributes of this command, a combination of SKIP_IF_EVER_ERROR, IGNORABLE and others.
java.lang.String	getId() Returns ID of this command.
protected abstract void	process(AuRequest request) Derived must override this method to process this command.
void	process(AuRequest request, boolean everError) Called to process the specified request.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

SKIP_IF_EVER_ERROR

public static final int SKIP_IF_EVER_ERROR

Whether to skip this command if previous commands ever caused errors. In other words, it decides whether to skip this command when process(AuRequest,boolean) is called with errorEver = true; This argument is used to control the behavior of process(AuRequest,boolean).

Part of the returned value of getFlags().

See Also:

Constant Field Values

IGNORABLE

public static final int IGNORABLE

Whether this command is ignorable. In other words, the ignorable command is dropped, if a new command is received before the ignorable command is processed.

Part of the returned value of getFlags().

See Also:

Constant Field Values

CTRL_GROUP

public static final int CTRL_GROUP

Whether this command belongs to the control group. The new control-group command is dropped if a control-group command is in the queue or in processing.

See Also:

Constant Field Values

IGNORE_OLD_EQUIV

public static final int IGNORE_OLD_EQUIV

Whether to drop the existent command (in the queue) if it is the same as the new arrival one. By the same we mean both command's ID and target are the same.

See Also:

Constant Field Values

IGNORE_IMMEDIATE_OLD_EQUIV

public static final int IGNORE_IMMEDIATE_OLD_EQUIV

Whether to drop the existent command (in the queue) if it is the same as the immediate following one. By the same we mean both command's ID and target are the same.

See Also:

Constant Field Values

Constructor Detail

Command

protected Command(java.lang.String id,
                  int flags)

Construct a command.

Note: once constructed, the command is registered to a global map automatically. And, it can be retrieved by AuRequest.getCommand(java.lang.String).

Parameters:

flags - a combination of SKIP_IF_EVER_ERROR, IGNORABLE and others

Method Detail

getFlags

public final int getFlags()

Returns the attributes of this command, a combination of SKIP_IF_EVER_ERROR, IGNORABLE and others.

getId

public final java.lang.String getId()

Returns ID of this command.

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public final boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

process

protected abstract void process(AuRequest request)

Derived must override this method to process this command.

process

public final void process(AuRequest request,
                          boolean everError)

Called to process the specified request. You don't override this method directly. Rather, override process(AuRequest).

Parameters:

everError - whether any error ever occured before processing this command. Notice that multiple commands might be processed in one execution.