Package org.basex.core

Class Command

java.lang.Object

org.basex.core.jobs.Job

org.basex.core.Command

Direct Known Subclasses:

ACreate, AlterBackup, AlterPassword, AlterUser, AQuery, Check, Close, Copy, CreateBackup, CreateUser, Dir, DropBackup, DropUser, Execute, Exit, Export, Flush, Grant, Help, Info, InfoDB, InfoIndex, InfoStorage, Inspect, Kill, List, Open, Password, RepoDelete, RepoInstall, RepoList, Restore, Set, ShowBackups, ShowOptions, ShowSessions, ShowUsers, Test

public abstract class Command
extends Job

This class provides the architecture for all internal command implementations. It evaluates queries that are sent by the GUI, the client or the standalone version.

Author:

BaseX Team 2005-24, BSD License, Christian Gruen

Field Summary

Fields

Modifier and Type	Field	Description
String[]	args	Command arguments.
protected Context	context	Database context.
Exception	exception	Exception during command execution.
protected InputSource	in	Optional input source.
boolean	openDB	Indicates if the command requires an opened database.
protected MainOptions	options	Convenience access to database options.
protected PrintOutput	out	Output stream.
Value	result	Cached result of a command execution.
protected StaticOptions	soptions	Convenience access to static options.
protected String	uri	Base URI.

Fields inherited from class org.basex.core.jobs.Job

state, updating

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Command(Perm perm, boolean openDB, String... args)	Constructor.
protected	Command(Perm perm, String... args)	Constructor for commands requiring no opened database.

Method Summary

Modifier and Type	Method	Description
protected void	addLocks(LockList list, int index)	Adds the name of the database that has been addressed by the argument index.
String	baseURI()	Returns the base URI.
Command	baseURI(String base)	Sets a base URI.
protected void	build(CmdBuilder cb)	Builds a string representation from the command.
protected static boolean	close(Context ctx, String db)	Closes the specified database if it is currently opened and only pinned once.
protected boolean	error(String msg, Object... ext)	Adds the error message to the message buffer info.
String	execute(Context ctx)	Executes the command and returns the result as string.
void	execute(Context ctx, OutputStream os)	Executes the command and prints the result to the specified output stream.
protected <E extends Enum<E>> E	getOption(Class<E> typ)	Returns the specified command option.
protected static <E extends Enum<E>> E	getOption(String string, Class<E> type)	Returns the specified command option.
String	info()	Returns command information.
protected boolean	info(String str, Object... ext)	Adds information on command execution.
void	init(Context ctx, OutputStream os)	Initializes the command execution.
boolean	newData(Context ctx)	Closes an open data reference and returns true if this command will change the Context.data() reference.
protected abstract boolean	run()	Executes the command and serializes the result (internal call).
boolean	run(Context ctx)	Runs the command without permission, data and concurrency checks.
boolean	run(Context ctx, OutputStream os)	Runs the command without permission, data and concurrency checks.
void	setInput(InputStream input)	Attaches an input stream.
void	setInput(InputSource input)	Attaches an input source.
boolean	stoppable()	Returns true if this command can be stopped.
boolean	supportsProg()	Returns true if this command returns a progress value.
String	toString()
String	toString(boolean password)	Returns a string representation of the command.
boolean	updated(Context ctx)	Checks if the command has updated any data.
boolean	updating(Context ctx)	Checks if the command performs updates/write operations.

Methods inherited from class org.basex.core.jobs.Job

active, addLocks, checkStop, detailedInfo, jc, memory, popJob, progressInfo, pushJob, register, shortInfo, state, stop, stopped, timeout, unregister

Methods inherited from class java.lang.Object

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

Field Detail

args

public final String[] args

Command arguments.

openDB

public final boolean openDB

Indicates if the command requires an opened database.

exception

public Exception exception

Exception during command execution.

result

public Value result

Cached result of a command execution.

context

protected Context context

Database context.

options

protected MainOptions options

Convenience access to database options.

soptions

protected StaticOptions soptions

Convenience access to static options.

out

protected PrintOutput out

Output stream.

in

protected InputSource in

Optional input source.

uri

protected String uri

Base URI.

Constructor Detail

Command

protected Command(Perm perm,
                  String... args)

Constructor for commands requiring no opened database.

Parameters:

perm - required permission

args - arguments

Command

protected Command(Perm perm,
                  boolean openDB,
                  String... args)

Constructor.

Parameters:

perm - required permission

openDB - requires an opened database

args - arguments

Method Detail

execute

public final void execute(Context ctx,
                          OutputStream os)
                   throws BaseXException

Executes the command and prints the result to the specified output stream. If an exception occurs, a BaseXException is thrown.

Parameters:

ctx - database context

os - output stream reference

Throws:

BaseXException - command exception

execute

public final String execute(Context ctx)
                     throws BaseXException

Executes the command and returns the result as string. If an exception occurs, a BaseXException is thrown.

Parameters:

ctx - database context

Returns:

string result

Throws:

BaseXException - command exception

setInput

public final void setInput(InputStream input)

Attaches an input stream.

Parameters:

input - input stream

setInput

public final void setInput(InputSource input)

Attaches an input source.

Parameters:

input - input source

run

public final boolean run(Context ctx)

Runs the command without permission, data and concurrency checks. Should only be called by other database commands.

Parameters:

ctx - database context

Returns:

result of check

info

public final String info()

Returns command information.

Returns:

info string

updating

public boolean updating(Context ctx)

Checks if the command performs updates/write operations.

Parameters:

ctx - database context

Returns:

result of check

updated

public boolean updated(Context ctx)

Checks if the command has updated any data.

Parameters:

ctx - database context

Returns:

result of check

newData

public boolean newData(Context ctx)

Closes an open data reference and returns true if this command will change the Context.data() reference. This method is only required by the GUI.

Parameters:

ctx - database context

Returns:

result of check

supportsProg

public boolean supportsProg()

Returns true if this command returns a progress value. This method is only required by the GUI.

Returns:

result of check

stoppable

public boolean stoppable()

Returns true if this command can be stopped. This method is only required by the GUI.

Returns:

result of check

init

public final void init(Context ctx,
                       OutputStream os)

Initializes the command execution.

Parameters:

ctx - database context

os - output stream

run

public final boolean run(Context ctx,
                         OutputStream os)

Runs the command without permission, data and concurrency checks.

Parameters:

ctx - database context

os - output stream

Returns:

result of check

toString

public final String toString(boolean password)

Returns a string representation of the command.

Parameters:

password - password flag

Returns:

result of check

baseURI

public Command baseURI(String base)

Sets a base URI.

Parameters:

base - base URI

Returns:

self reference

baseURI

public String baseURI()

Returns the base URI.

Returns:

base URI

toString

public final String toString()

Overrides:

toString in class Object

run

protected abstract boolean run()
                        throws IOException

Executes the command and serializes the result (internal call).

Returns:

success of operation

Throws:

IOException - I/O exception

build

protected void build(CmdBuilder cb)

Builds a string representation from the command. This string must be correctly built, as commands are sent to the server as strings.

Parameters:

cb - command builder

error

protected final boolean error(String msg,
                              Object... ext)

Adds the error message to the message buffer info.

Parameters:

msg - error message

ext - error extension

Returns:

false

info

protected final boolean info(String str,
                             Object... ext)

Adds information on command execution.

Parameters:

str - information to be added

ext - extended info

Returns:

true

getOption

protected final <E extends Enum<E>> E getOption(Class<E> typ)

Returns the specified command option.

Type Parameters:

E - token type

Parameters:

typ - options enumeration

Returns:

option

addLocks

protected final void addLocks(LockList list,
                              int index)

Adds the name of the database that has been addressed by the argument index. No databases will be added if the argument uses glob syntax.

Parameters:

list - lock list

index - argument index

getOption

protected static <E extends Enum<E>> E getOption(String string,
                                                 Class<E> type)

Returns the specified command option.

Type Parameters:

E - token type

Parameters:

string - string to be found

type - options enumeration

Returns:

option, or null if the option is not found

close

protected static boolean close(Context ctx,
                               String db)

Closes the specified database if it is currently opened and only pinned once.

Parameters:

ctx - database context

db - database to be closed

Returns:

true if opened database was closed