net.sf.reportengine.in

Class MultipleExternalSortedFilesTableInput

java.lang.Object

net.sf.reportengine.in.MultipleExternalSortedFilesTableInput

All Implemented Interfaces:

TableInput

public class MultipleExternalSortedFilesTableInput
extends Object
implements TableInput

Table input built from multiple files of NewRowEventsWrapper. The files provided in the constructor should have the values sorted. A priority queue will be used to store the values read from the list of files. The priority queue will sort the values and this input class will provide the NewRowEvent from this priority queue.

Author:

dragos balan

Constructor Summary

Constructors

Constructor and Description
MultipleExternalSortedFilesTableInput(List<File> files, NewRowComparator newRowComparator)

Method Summary

Modifier and Type	Method and Description
void	close() empty implementation
boolean	hasMoreRows() returns true if the priority queue with the external sorted files is empty
List<Object>	nextRow() next row is taken from the priority queue by polling the priority queue which returns the top FileWrapper.
void	open() empty implementation

Methods inherited from class java.lang.Object

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

Constructor Detail

MultipleExternalSortedFilesTableInput

public MultipleExternalSortedFilesTableInput(List<File> files,
                                             NewRowComparator newRowComparator)

Parameters:

externalSortedFiles - the list of files (each file having the values sorted)

newRowComparator - a comparator for new rows

Method Detail

open

public void open()

empty implementation

Specified by:

open in interface TableInput

close

public void close()

empty implementation

Specified by:

close in interface TableInput

nextRow

public List<Object> nextRow()

next row is taken from the priority queue by polling the priority queue which returns the top FileWrapper. On the topmost file wrapper, the poll method will be executed (which returns the top NewRowEvent) and, if not empty, the file wrapper is re-introduced into the priority queue (so that he participated in the next newRow() operation )

Specified by:

nextRow in interface TableInput

Returns:

an array of data objects

hasMoreRows

public boolean hasMoreRows()

returns true if the priority queue with the external sorted files is empty

Specified by:

hasMoreRows in interface TableInput

Returns:

true if the input has more rows to return