jimm.datavision.layout
Class LayoutEngine

java.lang.Object
  jimm.datavision.layout.LayoutEngine

Direct Known Subclasses:

ExcelLE, LaTeXLE, PDFLE, SortedLayoutEngine, SwingLE

public abstract class LayoutEngine
extends java.lang.Object

A layout engine is responsible for formatting and outputting report data. LayoutEngine is an abstract class. The Template design pattern is heavily used to provide a framework for concrete layout engine subclasses.

Author:

Jim Menard, jimm@io.com

Field Summary

protected Section	currentSection
protected boolean	newPage
protected java.io.PrintWriter	out
protected double	pageHeight
protected double	pageHeightUsed
protected int	pageNumber
protected double	pageWidth
static int	POINTS_PER_INCH The number of points per inch.
protected int	previousSectionArea
protected Report	report Set by report in Report.setLayoutEngine.
protected static int	SECT_DETAIL
protected static int	SECT_GROUP_FOOTER
protected static int	SECT_GROUP_HEADER
protected static int	SECT_PAGE_FOOTER
protected static int	SECT_PAGE_HEADER
protected static int	SECT_REPORT_FOOTER
protected static int	SECT_REPORT_HEADER
protected boolean	wantsMoreData

Constructor Summary

LayoutEngine()
Constructor.

LayoutEngine(java.io.PrintWriter out)
Constructor.

Method Summary

protected double	calcDetailHeight() Returns the total height of all detail sections.
protected double	calcPageFooterHeight() Returns the total height of all page footer sections.
protected double	calcReportFooterHeight() Returns the total height of all report footer sections.
protected double	calcSectionHeights(SectionArea area) Returns the total height of all sections in the specified list.
void	cancel() Called by someone else running the report to cancel all the hard work this layout engine has performed.
protected void	checkRemainingPageLength(boolean isLastRow, boolean includeDetail) Checks remaining page length and outputs a new page if we are at the bottom of the page.
protected void	closeOutput() Called by end to let this layout engine clean up a bit.
protected java.lang.String	currentSectionTypeAsString() Returns the current section type (header, footer, detail) as a string.
void	detail(boolean isLastRow) Called by the report when a single detail row needs to be output.
protected void	doEnd() Called by end as a chance to insert behavior when the report ends.
protected void	doEndPage() Called by endPage as a chance to insert behavior when a new page ends.
protected abstract void	doOutputField(Field field) Called by outputField as a chance to insert behavior when a field is output.
protected abstract void	doOutputImage(ImageField image) Called by outputImage as a chance to insert behavior when a image is output.
protected abstract void	doOutputLine(Line line) Called by outputLine as a chance to insert behavior when a line is output.
protected void	doOutputSection(Section sect) Called by outputSection as a chance to insert behavior when a section is output.
protected void	doStart() Called by start as a chance to insert behavior when the report starts.
protected void	doStartPage() Called by startPage as a chance to insert behavior when a new page starts.
void	end() Called by the report at the end of a report run.
protected void	endPage(boolean isLastPage) Ends a new page.
void	groupFooters(boolean isLastRow) Called by the report when group footers need to be output.
void	groupHeaders(boolean isLastRow) Called by the report when group headers need to be output.
protected void	outputField(Field field) Outputs a field.
protected void	outputImage(ImageField image) Outputs a image.
protected void	outputLine(Line line) Outputs a line.
protected void	outputSection(Section sect, int which) Outputs a section.
double	pageHeight() Returns the page height in points.
int	pageNumber() Returns the current page number.
double	pageWidth() Returns the page width in points.
void	setReport(Report r)
void	start() Called by the report at the beginning of a report run.
protected void	startPage() Starts a new page.
boolean	wantsMoreData() Called by a report before retrieving each row of data, this method returns true if this layout engine wants more data.

Methods inherited from class java.lang.Object

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

Field Detail

POINTS_PER_INCH

public static final int POINTS_PER_INCH

The number of points per inch.

See Also:

Constant Field Values

SECT_REPORT_HEADER

protected static final int SECT_REPORT_HEADER

See Also:

Constant Field Values

SECT_REPORT_FOOTER

protected static final int SECT_REPORT_FOOTER

See Also:

Constant Field Values

SECT_PAGE_HEADER

protected static final int SECT_PAGE_HEADER

See Also:

Constant Field Values

SECT_PAGE_FOOTER

protected static final int SECT_PAGE_FOOTER

See Also:

Constant Field Values

SECT_GROUP_HEADER

protected static final int SECT_GROUP_HEADER

See Also:

Constant Field Values

SECT_GROUP_FOOTER

protected static final int SECT_GROUP_FOOTER

See Also:

Constant Field Values

SECT_DETAIL

protected static final int SECT_DETAIL

See Also:

Constant Field Values

report

protected Report report

Set by report in Report.setLayoutEngine.

pageNumber

protected int pageNumber

out

protected java.io.PrintWriter out

newPage

protected boolean newPage

pageHeight

protected double pageHeight

pageWidth

protected double pageWidth

pageHeightUsed

protected double pageHeightUsed

currentSection

protected Section currentSection

wantsMoreData

protected boolean wantsMoreData

previousSectionArea

protected int previousSectionArea

Constructor Detail

LayoutEngine

public LayoutEngine()

Constructor.

LayoutEngine

public LayoutEngine(java.io.PrintWriter out)

Constructor.

Parameters:

out - output print writer

Method Detail

setReport

public void setReport(Report r)

pageWidth

public double pageWidth()

Returns the page width in points. This value is only valid after start() has been called.

Returns:

the page width in points

pageHeight

public double pageHeight()

Returns the page height in points. This value is only valid after start() has been called.

Returns:

the page height in points

wantsMoreData

public boolean wantsMoreData()

Called by a report before retrieving each row of data, this method returns true if this layout engine wants more data. Concrete subclasses can set the wantsMoreData instance variable to false if the user cancells a report run, for example.

Returns:

true if this layout engine would like more data

cancel

public void cancel()

Called by someone else running the report to cancel all the hard work this layout engine has performed.

start

public void start()

Called by the report at the beginning of a report run.

By this time, report will be non-null because we have been added to a report (which in turn sets our report instance variable).

doStart

protected void doStart()

Called by start as a chance to insert behavior when the report starts.

end

public void end()

Called by the report at the end of a report run.

doEnd

protected void doEnd()

Called by end as a chance to insert behavior when the report ends.

closeOutput

protected void closeOutput()

Called by end to let this layout engine clean up a bit.

groupHeaders

public void groupHeaders(boolean isLastRow)

Called by the report when group headers need to be output. Once one group header is output, we output all remaining group headers.

We need to explicitly evaluate all formulas in the headers that will be output because checkRemainingPageLength(boolean, boolean) causes formulas in detail and footers to be evaluated. Those formulas may depend upon values in these headers.

Parameters:

isLastRow - if true, this is the last row of the report

detail

public void detail(boolean isLastRow)

Called by the report when a single detail row needs to be output.

Parameters:

isLastRow - if true, this is the last row of the report

groupFooters

public void groupFooters(boolean isLastRow)

Called by the report when group footers need to be output. When one group footer is output, we make sure all of the footers before (above) it are also output.

Parameters:

isLastRow - if true, this is the last row of the report

checkRemainingPageLength

protected void checkRemainingPageLength(boolean isLastRow,
                                        boolean includeDetail)

Checks remaining page length and outputs a new page if we are at the bottom of the page.

Parameters:

isLastRow - if true, this is the last row of the report

includeDetail - if true, include height of detail sections

pageNumber

public int pageNumber()

Returns the current page number.

Returns:

the current page number

startPage

protected void startPage()

Starts a new page.

doStartPage

protected void doStartPage()

Called by startPage as a chance to insert behavior when a new page starts.

endPage

protected void endPage(boolean isLastPage)

Ends a new page.

Parameters:

isLastPage - if true, this is the last page of the report

doEndPage

protected void doEndPage()

Called by endPage as a chance to insert behavior when a new page ends.

outputSection

protected void outputSection(Section sect,
                             int which)

Outputs a section.

Parameters:

sect - the section to output

which - the type of section (for example, SECT_PAGE_FOOTER)

doOutputSection

protected void doOutputSection(Section sect)

Called by outputSection as a chance to insert behavior when a section is output.

Parameters:

sect - a section

outputField

protected void outputField(Field field)

Outputs a field.

Parameters:

field - the field to output

doOutputField

protected abstract void doOutputField(Field field)

Called by outputField as a chance to insert behavior when a field is output.

Parameters:

field - a field

outputImage

protected void outputImage(ImageField image)

Outputs a image.

Parameters:

image - the image field to output

doOutputImage

protected abstract void doOutputImage(ImageField image)

Called by outputImage as a chance to insert behavior when a image is output.

Parameters:

image - an image field

outputLine

protected void outputLine(Line line)

Outputs a line.

Parameters:

line - the line to output

doOutputLine

protected abstract void doOutputLine(Line line)

Called by outputLine as a chance to insert behavior when a line is output.

Parameters:

line - a line

currentSectionTypeAsString

protected java.lang.String currentSectionTypeAsString()

Returns the current section type (header, footer, detail) as a string.

Returns:

a string representation of the current section type

calcSectionHeights

protected double calcSectionHeights(SectionArea area)

Returns the total height of all sections in the specified list.

Parameters:

area - a section area

Returns:

the total height of all sections in the list

calcDetailHeight

protected double calcDetailHeight()

Returns the total height of all detail sections.

Returns:

the total height of all detail sections

calcPageFooterHeight

protected double calcPageFooterHeight()

Returns the total height of all page footer sections.

Returns:

the total height of all page footer sections

calcReportFooterHeight

protected double calcReportFooterHeight()

Returns the total height of all report footer sections.

Returns:

the total height of all report footer sections