org.unix4j.processor

Class MultipleInputLineProcessor

java.lang.Object

org.unix4j.processor.MultipleInputLineProcessor

All Implemented Interfaces:

LineProcessor

Direct Known Subclasses:

RedirectInputLineProcessor

public class MultipleInputLineProcessor
extends Object
implements LineProcessor

A line processor for multiple inputs processing the same operation for each input object individually. An operation here is another LineProcessor reading the lines passed to it from the standard input.

The processLine(Line) method does nothing and returns false indicating that the (standard) input is not read by this processor. The finish() method reads the lines from the Input object passed to the constructor and passes them as input to the delegate processor performing the real work.

Constructor Summary

Constructors

Constructor and Description
MultipleInputLineProcessor(List<? extends Input> inputs, InputProcessor processor, LineProcessor output) Constructor with input objects (usually file operands of the command) and the input processor of the command that reads from the standard input.

Method Summary

Modifier and Type	Method and Description
protected void	beginMultiple(List<? extends Input> inputs, LineProcessor output) Called once at the beginning before iterating over the Input objects in the given inputs list.
void	finish() Performs the following operations to process all Input objects that have been passed to the constructor: Calls beginMultiple(..) Iterates over all input objects in sequence Calls InputProcessor.begin(Input, LineProcessor) Calls InputProcessor.processLine(Input, Line, LineProcessor) for every line in the current input Calls InputProcessor.finish(Input, LineProcessor) Calls finishMultiple(..)
protected void	finishMultiple(List<? extends Input> inputs, LineProcessor output) Called once at the end after iterating over the Input objects in the given inputs list.
boolean	processLine(Line line) Processes a single line and returns true if this LineProcessor is ready to process more lines.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultipleInputLineProcessor

public MultipleInputLineProcessor(List<? extends Input> inputs,
                                  InputProcessor processor,
                                  LineProcessor output)

Constructor with input objects (usually file operands of the command) and the input processor of the command that reads from the standard input.

Parameters:

inputs - the input devices, usually file operands of the command

processor - the operation applied to every input in the given inputs list

Method Detail

processLine

public boolean processLine(Line line)

Description copied from interface: LineProcessor

Processes a single line and returns true if this LineProcessor is ready to process more lines. Returning false indicates that the process can be finished because subsequent lines would not change the result anyway.

Specified by:

processLine in interface LineProcessor

Parameters:

line - the line to process

Returns:

true if this LineProcessor is ready to process more lines, and false if it does not require any more input lines

finish

public void finish()

Performs the following operations to process all Input objects that have been passed to the constructor:

1. Calls beginMultiple(..)
2. Iterates over all input objects in sequence
3. Calls InputProcessor.begin(Input, LineProcessor)
4. Calls InputProcessor.processLine(Input, Line, LineProcessor) for every line in the current input
5. Calls InputProcessor.finish(Input, LineProcessor)
6. Calls finishMultiple(..)

Specified by:

finish in interface LineProcessor

beginMultiple

protected void beginMultiple(List<? extends Input> inputs,
                             LineProcessor output)

Called once at the beginning before iterating over the Input objects in the given inputs list.

The DEFAULT implementation performs no operation.

Parameters:

inputs - the input object being iterated next

output - the output to write to

finishMultiple

protected void finishMultiple(List<? extends Input> inputs,
                              LineProcessor output)

Called once at the end after iterating over the Input objects in the given inputs list.

The DEFAULT implementation calls output.finish() and closes all input objects.

Parameters:

inputs - the input object being iterated next

output - the output to write to