create barcode image c# Defining and using a filter in Java

Drawer ECC200 in Java Defining and using a filter

Defining and using a filter
Data Matrix 2d Barcode Encoder In Java
Using Barcode creation for Java Control to generate, create ECC200 image in Java applications.
www.OnBarcode.com
Data Matrix Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
In a plain Lucene environment, the application developer needs to handle instances of filters and apply them to the queries manually. This imperative approach can be quite cumbersome, especially when the code tries to benefit from filter caching.
UPC Code Maker In Java
Using Barcode creator for Java Control to generate, create GTIN - 12 image in Java applications.
www.OnBarcode.com
UPC-A Supplement 2 Generator In Java
Using Barcode creator for Java Control to generate, create GS1 - 12 image in Java applications.
www.OnBarcode.com
Declaring a filter in Hibernate Search
Draw Code 39 Full ASCII In Java
Using Barcode generation for Java Control to generate, create ANSI/AIM Code 39 image in Java applications.
www.OnBarcode.com
PDF-417 2d Barcode Drawer In Java
Using Barcode drawer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Hibernate Search goes a step further and handles filters as resources. Just as you don t need to manually open index readers when using Hibernate Search, filter instances are managed transparently and declaratively for you. Let s assume your Filter implementation is ready to be used. Hibernate Search lets you associate a name with it. Later we ll show how to enable filters declaratively on queries using their names, but for now look at listing 8.2, which describes how to define a filter in Hibernate Search. A filter definition annotation (@FullTextFilterDef) is placed on any of the indexed entities but is not specific to the entity it s placed on. Each definition has a name that must be unique in the deployment unit.
Making Barcode In Java
Using Barcode maker for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
USD - 8 Creator In Java
Using Barcode encoder for Java Control to generate, create USD - 8 image in Java applications.
www.OnBarcode.com
Listing 8.2 Declare a filter using the @FullTextFilterDef annotation
Drawing Data Matrix 2d Barcode In Objective-C
Using Barcode creation for iPad Control to generate, create ECC200 image in iPad applications.
www.OnBarcode.com
Data Matrix 2d Barcode Encoder In None
Using Barcode generator for Online Control to generate, create DataMatrix image in Online applications.
www.OnBarcode.com
@Entity @Indexed @Table(name="PRODUCTS") Filters have a @FullTextFilterDef( name (reference) name="distributor", impl=DistributorFilter.class) Filter public class Item { implementation ... }
Print Code 128 Code Set A In None
Using Barcode generation for Online Control to generate, create Code-128 image in Online applications.
www.OnBarcode.com
Generate ECC200 In .NET Framework
Using Barcode creation for VS .NET Control to generate, create Data Matrix image in VS .NET applications.
www.OnBarcode.com
You can define more than one filter per class by using @FullTextFilterDefs; this annotation accepts an array of @FullTextFilterDef. DistributorFilter in listing 8.2 must have a no-arg constructor. This constraint can be cumbersome in some situations; for example, you might want to reuse a Filter implementation that doesn t provide a no-arg constructor (like QueryWrapperFilter). Hibernate Search lets you provide a Filter factory implementation instead of a Filter implementation. Simply set FullTextFilterDef.impl() to the filter factory class. A filter factory class is a class where one of the methods is annotated with @Factory. Listing 8.3 is an example of such an approach; a DistributorFilterFactory provides a properly initialized QueryWrapperFilter.
Creating PDF417 In None
Using Barcode printer for Excel Control to generate, create PDF417 image in Microsoft Excel applications.
www.OnBarcode.com
Draw QR Code JIS X 0510 In Objective-C
Using Barcode creator for iPad Control to generate, create QR-Code image in iPad applications.
www.OnBarcode.com
Listing 8.3 Use a Filter factory to build filters needed for initialization Has a no-arg constructor
Code-128 Creation In Objective-C
Using Barcode maker for iPad Control to generate, create Code-128 image in iPad applications.
www.OnBarcode.com
EAN13 Generation In .NET
Using Barcode generation for Reporting Service Control to generate, create EAN-13 Supplement 5 image in Reporting Service applications.
www.OnBarcode.com
public class WarnerDistributorFilterFactory {
Read EAN / UCC - 13 In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Universal Product Code Version A Generator In Visual Studio .NET
Using Barcode drawer for Reporting Service Control to generate, create UPC-A Supplement 2 image in Reporting Service applications.
www.OnBarcode.com
Factory method @Factory public Filter buildDistributorFilter() { Term term = new Term( "distributor.name", "Warner" ); Query query = new TermQuery( term );
UPC Code Encoder In None
Using Barcode printer for Online Control to generate, create UPC Symbol image in Online applications.
www.OnBarcode.com
Barcode Encoder In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Filter filter = new QueryWrapperFilter( query ); return filter; }
Build the QueryWrapperFilter
Filters: cross-cutting restrictions
@Entity @Indexed @Table(name="PRODUCTS") @FullTextFilterDef( name="category", impl=WarnerDistributorFilterFactory.class) public class Item { ... }
Define a Filter
D factory
B The factory method must return Filter instances and be annotated with @Factory. C A QueryWrapperFilter is initialized with the distributor-filtering query. D
The filter definition takes a filter factory as an implementation. The method providing the filter instance must be marked as @Factory. Filters show their real power when they are cached. Hibernate Search offers you two layers of caching:
Caching of the Filter instances themselves Caching the DocIdSet result from the filter execution (for a given IndexReader)
Let s have a deeper look.
CACHING FILTERS
Caching the actual filter instances allows a given filter to be used across many (concurrent) filter.getDocIdSet() calls. This is especially useful if the creation of the filter is costly or if it does a costly evaluation. On top of filter-instance caching, DocIdSet results can be cached by Hibernate Search. There are some conditions for returning the same DocIdSet instance:
The same filter instance is targeted. The same parameters are used to initialize the query and the filter instance. The same IndexReader (think of a view in Lucene directories) is used.
This DocIdSet caching is known in the Lucene world as filter caching, and in Hibernate Search it s essentially implemented by wrapping the filter instance around a customized version of Lucene s CachingWrapperFilter. The benefit of caching the DocIdSet is, of course, that expensive recomputations can be avoided. Caching results and caching DocIdSet are synonymous.
Make sure your Filter implementation is thread-safe when you enable caching.
In most cases, enabling both levels of filter caching is the right choice, and for that reason it s the default in Hibernate Search (FilterCacheModeType.INSTANCE_AND_ DOCIDSETRESULTS). Note that to cache results, you must also cache the instance. In some situations, however, it might be useful to cache only the Filter instance. For example, a filter could use its own specific caching mechanism, or the filter results could change dynamically because of application-specific events, making DocIdSet caching unnecessary or even harmful. You can keep filter instance caching enabled
Copyright © OnBarcode.com . All rights reserved.