Package net.sf.jasperreports.barcode4j

package net.sf.jasperreports.barcode4j
Contains classes for the built-in Barcode4J component.

The Barcode4J Component

This component relies on the Barcode4J library (http://barcode4j.sourceforge.net).
Unlike the Barbecue barcode component, there is only one component per Barcode4J barcode type. All the barcode's components derive from a base type which defines its common attributes.

All barcodes in this library include a code expression, which provides the textual data to be encoded in the barcode, and an optional expression that provides a pattern to be applied on the message displayed in the barcode. Delayed evaluation of the barcode can be configured using the two evaluation attributes and works in the same way as for Barbecue barcodes.

Several optional barcode rendering attributes can be set:
  • orientation - specifies how the barcode and any accompanying text are to be oriented when rendered. There are 4 possible values:
    • 0 - indicates that the barcode is to be rendered in the default orientation (which for linear barcodes is with vertical bars arranged from left to right)
    • 90 - indicates that the barcode is to be rotated anti-clockwise by 90 degrees
    • 180 - indicates that the barcode is to be rotated anti-clockwise by 180 degrees
    • 270 - indicates that the barcode is to be rotated anti-clockwise by 270 degrees
  • moduleWidth - specifies the width (in pixels) of the thinnest bar/module.
  • textPosition - Sets the placement of the human-readable barcode message. It has three possible values: none - meaning no human-readable message, and bottom and top.
    Note that the message and barcode are oriented together as a unit, so if the orientation is set to 180 and the text position to top, the code appears reversed and the text appears upside down beneath the image.
  • quietZone - Specifies the width of the quiet zone (in pixels).
  • verticalQuietZone - Specifies the height of the vertical quiet zone (in pixels).
Concrete barcode types extend the base type by adding further attributes supported by the specific symboloy:
  • Codabar barcodes have a wideFactor attribute that specifies the factor between the width of wide bars and the width of narrow bars.
  • Code128 barcodes do not have any specific attributes.
  • EAN128, EAN13, EAN8, UPCA and UPCE barcodes have a checksumMode attribute which indicates how the check digit is to be handled. The attribute accepts four values:
    • add - adds the checksum to the data;
    • check - indicates that the data should already contain a checksum;
    • ignore - doesn't expect or add a checksum to the data;
    • auto - attempts to detect whether a checksum is already present in the data or one should be added.
  • Data Matrix barcodes can be configured to render as a square or rectangle by the shape attribute.
  • Code39 barcodes have a checksumMode attribute, a displayChecksum attribute that controls whether the human-readable message shows the checksum character, a displayStartStop attribute which decides whether start/stop characters are to be displayed in the human-readable message, extendedCharSetEnabled to indicate that the barcode can display characters from the entire 7-bit ASCII set, intercharGapWidth to control the width between the characters and a wideFactor attribute.
  • Interleaved2Of5 barcodes can specify checksumMode, displayChecksum and wideFactor attributes with the same meanings as in Code39 barcodes.
  • RoyalMailCustomer and USPSIntelligentMail barcodes have a checksumMode attribute, an intercharGapWidth attribute, an ascenderHeight attribute which sets the length of the bar ascender/descender, and a trackHeight attribute which provides the height of the barcode track.
  • POSTNET barcodes can specify checksumMode, displayChecksum and intercharGapWidth attributes, plus shortBarHeight for setting the height of the short bar, and baselinePosition which can be top or bottom to indicate how bars should align.
  • PDF417 barcode can control the number of columns and rows with the minColumns, maxColumns, minRows, maxRows and widthToHeightRatio attributes. The error correction level can be set using the errorCorrectionLevel attribute.
  • QRCode barcode can control its error correction level using the errorCorrectionLevel attribute.
The object model for the barcode components uses BarcodeComponent as base class and concrete classes for each barcode type.

When a report that contains barcodes is filled, the data and attributes of the barcode are collected into an object and passed to an image producer whose responsibility is to create a renderer for the barcode. The image producer implements the BarcodeImageProducer interface. As for Barbecue barcode elements, the resulting images have the size of the design barcode element and use RetainShape as scale type.

Determining which image producer to use for a barcode component element relies on custom properties defined at the element, report and global levels. The net.sf.jasperreports.components.barcode4j.image.producer property can have a value of the name of the class that implements the image producer interface or an alias that has been set for such a class, using a property of the form net.sf.jasperreports.components.barcode4j.image.producer.<alias>. JasperReports has two barcode image producer implementations: one which renders the barcode in SVG format and one which renders the barcode as a rasterized image. The first implementation is registered under the svg alias and is used by default; the second one has image as alias and can be used by changing the net.sf.jasperreports.components.barcode4j.image.producer.<alias> property at any level.

The SVG barcode image producer uses the Barcode4J API to export the barcode to SVG, then it creates an SVG renderer based on the Batik SVG library. Hence, this option introduces a dependency on Batik for viewing or exporting a report that includes barcodes.

The rasterized image producer draws the barcode on a PNG image which can be then displayed in the generated report. This producer uses further properties, set at the same levels as the image producer property, to allow the customization of the generated image.