CommandTask (LSST CCS Graphical User Interface 4.2.11 API)

java.lang.Object
- org.lsst.ccs.gconsole.agent.command.CommandTask

```
public class CommandTask
extends Object
```
A CommandTask sends a command to a target subsystem and handles the responses. Methods are provided to check if the command processing is complete, to wait for its completion, and to retrieve the result.

Author:

onoprien

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`CommandTask(CommandSender sender, CommandHandle handle, Duration timeout, String destination, String command, Object[] args)` Creates a `CommandTask` with an explicit list of raw (not converted to strings) arguments.
`protected`	`CommandTask(String destination, String command, CommandSender sender, CommandHandle handle, Duration timeout)` Creates a `CommandTask`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`cancel()` Cancels this command task.
`Object`	`get()` Waits if necessary for the command execution to complete, and then returns its result.
`Object[]`	`getArguments()` Returns the command arguments.
`String`	`getCommand()` Returns the command as a string in `method arguments` format.
`Object`	`getProperty(String key)` Returns the value of the specified user-supplied property.
`Object`	`getResult()` Waits if necessary for the command execution to complete, and then returns its result or exception.
`boolean`	`isCancelled()` Returns `true` if this command task was canceled before it completed normally.
`boolean`	`isDone()` Returns true if this command task has completed.
`Object`	`putProperty(String key, Object value)` Attaches a user-supplied property to this task.
`Object`	`removeProperty(String key)` Removes a previously attached user-supplied property.
`protected void`	`send()` Triggers sending the command to the target subsystem.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CommandTask
```
protected CommandTask(CommandSender sender,
                      CommandHandle handle,
                      Duration timeout,
                      String destination,
                      String command,
                      Object[] args)
```
    Creates a CommandTask with an explicit list of raw (not converted to strings) arguments.
    
    Parameters:
    
    sender - CommandSender that created this task.
    
    handle - Object to be notified of responses to the command.
    
    timeout - Timeout. Zero means the command will never time out. Negative timeout means its absolute value will be used and the custom timeout suggested by the target subsystem through an ACK will be ignored.
    
    destination - Command destination, in "subsystem/component0/.../componentN" format. If null, the command is assumed to contain destination in "destination/method" format.
    
    command - Command name.
    
    args - Command arguments.
  - CommandTask
```
protected CommandTask(String destination,
                      String command,
                      CommandSender sender,
                      CommandHandle handle,
                      Duration timeout)
```
    Creates a CommandTask.
    
    Parameters:
    
    destination - Command destination in subsystem/path format.
    
    command - Command in "method arguments" format.
    
    sender - CommandSender that created this task.
    
    handle - Object to be notified of responses to the command.
    
    timeout - Timeout. Zero means the command will never time out. Negative timeout means its absolute value will be used and the custom timeout suggested by the target subsystem through an ACK will be ignored.
- Method Detail
  - send
```
protected void send()
```
    Triggers sending the command to the target subsystem.
  - get
```
public Object get()
           throws IllegalStateException,
                  InterruptedException,
                  org.lsst.ccs.messaging.CommandRejectedException,
                  CancellationException,
                  TimeoutException,
                  ExecutionException
```
    Waits if necessary for the command execution to complete, and then returns its result.
    
    Returns:
    
    The command result.
    
    Throws:
    
    IllegalStateException - If the command cannot be sent.
    
    InterruptedException - If the current thread was interrupted while waiting.
    
    org.lsst.ccs.messaging.CommandRejectedException - If the command was rejected by the target subsystem.
    
    CancellationException - If the command was canceled.
    
    TimeoutException - If the command timed out.
    
    ExecutionException - If an exception was thrown by the target subsystem while executing the command, or the result of the execution is an instance of Throwable.
  - getResult
```
public Object getResult()
                 throws InterruptedException
```
    Waits if necessary for the command execution to complete, and then returns its result or exception. Unlike the get() method, this method does not throw command-related exceptions. Instead, the outcome of this command task is reported through the return value.
    
    Returns:
    
    The command result, or the exception that would be thrown by the get() method.
    
    Throws:
    
    InterruptedException - If the current thread was interrupted while waiting.
  - cancel
```
public boolean cancel()
```
    Cancels this command task. Once the command is canceled, CommandHandle methods will not be called, and the get() method will throw CancellationException. The target subsystem will not be notified of cancellation.
    
    Returns:
    
    False if the command task could not be canceled, typically because it has already completed normally; true otherwise.
  - isCancelled
```
public boolean isCancelled()
```
    Returns true if this command task was canceled before it completed normally.
    
    Returns:
    
    True if the command was canceled.
  - isDone
```
public boolean isDone()
```
    Returns true if this command task has completed. Completion may be due to normal completion, an exception, or cancellation.
    
    Returns:
    
    True if this task completed.
  - getCommand
```
public String getCommand()
```
    Returns the command as a string in method arguments format.
    
    Returns:
    
    Command string.
  - getArguments
```
public Object[] getArguments()
```
    Returns the command arguments.
    
    Returns:
    
    Command arguments.
  - putProperty
```
public Object putProperty(String key,
                          Object value)
```
    Attaches a user-supplied property to this task.
    
    Parameters:
    
    key - Property name.
    
    value - Property value.
    
    Returns:
    
    Previous value associated with key, or null if there was no mapping for key.
  - removeProperty
```
public Object removeProperty(String key)
```
    Removes a previously attached user-supplied property.
    
    Parameters:
    
    key - Property name.
    
    Returns:
    
    Previous value associated with key, or null if there was no mapping for key.
  - getProperty
```
public Object getProperty(String key)
```
    Returns the value of the specified user-supplied property.
    
    Parameters:
    
    key - Property name.
    
    Returns:
    
    Property value, or null if a property with the specified name does not exist.

Class CommandTask

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CommandTask

CommandTask

Method Detail

send

get

getResult

cancel

isCancelled

isDone

getCommand

getArguments

putProperty

removeProperty

getProperty