# All Classes

- All Classes Interface Summary Class Summary Exception Summary
  Class | Description
  --- | ---
  AbortException | Exception generated when the user signals an intention to abort a task.
  AbstractChoiceParameter<T,​C> | Abstract superclass for parameters that permit choices from a given list of typed options.
  BooleanParameter | Parameter value representing a boolean value.
  ChoiceParameter<T> | Parameter whose legal value must be one of a disjunction of given values.
  DoubleParameter | Parameter representing a double precision number.
  Environment | Defines an execution environment within which tasks can operate.
  Executable | Defines an object which does the work of a task without any further user or environment interaction.
  ExecutionException | Exception generated when a task does not complete correctly for some known reason.
  InputStreamParameter | Parameter which can provide an input stream based on its value.
  IntegerParameter | Parameter representing an integer value.
  InvokeUtils | Provides some utility functions used by classes which invoke tasks.
  LineEnvironment | Execution environment for use from the command line.
  LineFormatter | Compact log record formatter.
  LineWord | Represents a single word on the command line used as by LineEnvironment.
  LongParameter | Parameter representing a long integer value.
  MultiChoiceParameter<C> | MultiParameter that returns an array of values from a given typed list of options.
  MultiParameter | Marker interface which marks a parameter as one which can have multiple appearances on the command line.
  MultiTaskInvoker | Invokes tasks from a command line when the tasks are available from an `ObjectFactory`.
  ObjectFactoryParameter<T> | Parameter whose (user-supplied) string values correspond to nicknames from an `ObjectFactory`.
  OutputStreamParameter | Parameter for selecting an output stream to write to.
  Parameter<T> | A Parameter describes the function of one of a task's parameters.
  ParameterValueException | Exception generated when the value of a parameter is invalid.
  SingleTaskInvoker | Invoker which only knows how to invoke a single given task.
  StringParameter | Parameter for holding string values.
  Task | Defines a user-level task.
  TaskException | Superclass for exceptions in the task package.
  TerminalEnvironment | Implementation of Environment which accepts an initial command line, and communicates with the user using standard input and standard output.
  TerminalInvoker | Invokes Task objects in a way suitable for use from the `main` method, using a command line interface.
  URLParameter | Parameter representing a URL value.
  UsageException | An Exception thrown when a task is invoked with the wrong usage.