create barcode image c# Writing simple custom bridges in Java

Drawer ECC200 in Java Writing simple custom bridges

Writing simple custom bridges
Creating Data Matrix In Java
Using Barcode printer for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
www.OnBarcode.com
Read Data Matrix ECC200 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Often a bridge is simply a conversion routine from an object representation to a string representation. You might also have to implement the routine to convert the string representation back to the object if the bridge is used on an identifier property or on a property meant to be projected. Let s first discover how to write the simplest bridge: the conversion routine from an object to a string.
GS1 DataBar-14 Maker In Java
Using Barcode printer for Java Control to generate, create GS1 DataBar-14 image in Java applications.
www.OnBarcode.com
Printing UPC A In Java
Using Barcode drawer for Java Control to generate, create Universal Product Code version A image in Java applications.
www.OnBarcode.com
ONE-WAY SIMPLE CUSTOM BRIDGES
Making QR In Java
Using Barcode generation for Java Control to generate, create Quick Response Code image in Java applications.
www.OnBarcode.com
Barcode Maker In Java
Using Barcode maker for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Hibernate Search offers a simple bridge interface to satisfy such cases: org.hibernate.search.bridge.StringBridge. Let s implement the bridge used in listing 4.1. Listing 4.4 shows both the declaration and the implementation of the field bridge. The bridge implementation is a StringBridge that rounds and pads doubles.
Generate PDF-417 2d Barcode In Java
Using Barcode creator for Java Control to generate, create PDF-417 2d barcode image in Java applications.
www.OnBarcode.com
Print Code 2/5 In Java
Using Barcode creator for Java Control to generate, create C 2 of 5 image in Java applications.
www.OnBarcode.com
Listing 4.4 Declare the use of a bridge and implement it
ECC200 Recognizer In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
ECC200 Creator In None
Using Barcode maker for Online Control to generate, create ECC200 image in Online applications.
www.OnBarcode.com
@Entity @Indexed public class Item { @Field @FieldBridge( impl=PaddedRoundedPriceBridge.class ) private double price; ... }
USS Code 39 Creator In None
Using Barcode encoder for Online Control to generate, create Code 39 image in Online applications.
www.OnBarcode.com
Painting DataMatrix In VS .NET
Using Barcode maker for VS .NET Control to generate, create Data Matrix ECC200 image in VS .NET applications.
www.OnBarcode.com
B Declare bridge
Create Code 39 Full ASCII In None
Using Barcode generator for Excel Control to generate, create Code 3/9 image in Microsoft Excel applications.
www.OnBarcode.com
Barcode Recognizer In Visual Basic .NET
Using Barcode Control SDK for .NET Control to generate, create, read, scan barcode image in VS .NET applications.
www.OnBarcode.com
implementation
Encoding PDF417 In None
Using Barcode creation for Software Control to generate, create PDF417 image in Software applications.
www.OnBarcode.com
EAN-13 Generation In Visual Basic .NET
Using Barcode encoder for .NET Control to generate, create EAN13 image in .NET framework applications.
www.OnBarcode.com
/** * Round a price by range of 5, going to the upper boundaries * pad the result with up to 3 non-significant 0 Implement * Accept double and Double StringBridge */ public class PaddedRoundedPriceBridge implements StringBridge { public static int PAD = 3; public static double ROUND = 5d; Convert property public String objectToString(Object value) { if ( value == null ) return null;
Data Matrix ECC200 Generation In Java
Using Barcode creation for Android Control to generate, create DataMatrix image in Android applications.
www.OnBarcode.com
PDF-417 2d Barcode Encoder In Java
Using Barcode drawer for Android Control to generate, create PDF417 image in Android applications.
www.OnBarcode.com
C value into String
USS-128 Creator In Visual Studio .NET
Using Barcode creator for ASP.NET Control to generate, create EAN / UCC - 13 image in ASP.NET applications.
www.OnBarcode.com
Barcode Generator In VB.NET
Using Barcode encoder for VS .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
Null strings are not indexed
Mapping more advanced data structures
if (value instanceof Double) { long price = round( (Double) value ); return pad(price); } else { throw new IllegalArgumentException( PaddedRoundedPriceBridge.class + " used on a non double type: " + value.getClass() ); } }
E Raise runtime errors exceptions on
private long round(double price) { double rounded = Math.floor( price / ROUND ) * ROUND; if ( rounded != price ) rounded+= ROUND; //we round up return (long) rounded; } Padding
implementation private String pad(long price) { String rawLong = Long.toString(price); if (rawLong.length() > PAD) throw new IllegalArgumentException( "Try to pad on a number too big" ); StringBuilder paddedLong = new StringBuilder(); for ( int padIndex = rawLong.length() ; padIndex < PAD ; padIndex++ ) { paddedLong.append( '0' ); } return paddedLong.append( rawLong ).toString(); }
B Use the PaddedRoundedPriceBridge to index the price property. C A simple oneway bridge must implement the method objectToString. The value passed is the property value, the price in this example. D Null objects should generally return a null string; the null element is not indexed. E Unexpected inputs should raise a runtime exception. F Padding is an important technique in Lucene to enable a ranged query and sorting on numbers. The main method to pay attention to is objectToString. This method passes the property value (or the entity instance if the bridge is a class bridge) and expects a string representation in return. Lucene will index this string. While you can do pretty much what you want in the bridge implementation, this example shows a couple of interesting implementation decisions. Like all built-in bridges, this bridge returns null when a null object is provided. Hibernate Search does not add null string values to the index. 3 and especially section 3.1.2 explain the reasons behind this decision. While it is recommended to return a null string when a null object is passed, your bridge can go against this rule. When the bridge receives an unexpected type (in the custom bridge example, any type that is not a double is unexpected), a runtime exception is raised and indexing fails. Once again, a bridge can decide to ignore the issue and degrade
Mapping the unexpected: custom bridges
nicely, but in most cases the right approach is to raise an alarm to the developer in the form of an exception. A very useful technique is used in this bridge example: number padding. The only data structure Lucene understands is a string. In particular, comparisons are entirely based on strings. Unfortunately, string comparisons and number comparisons don t play together well. The number 2 is inferior to the number 12, but the string "2" is superior to the string "12". One way to align the number and string comparison is to pad numbers. Padding consists of adding nonsignificant leading zeros; thus, "002" is inferior to "012". The main drawback of this technique is that the number of leading zeros has to be decided upfront. Changing the maximum allowed value would mean reindexing all the elements. The bridge we ve just designed is not sufficient to bridge an identifier property or to bridge properties that need to be projected. The next section describes the extra steps required to make a simple two-way bridge.
Copyright © OnBarcode.com . All rights reserved.