download barcode font for vb.net Use MatchAllDocsQuery to build negative queries in Java

Drawer DataMatrix in Java Use MatchAllDocsQuery to build negative queries

Listing 8.9 Use MatchAllDocsQuery to build negative queries
Data Matrix ECC200 Drawer In Java
Using Barcode generation for Java Control to generate, create Data Matrix image in Java applications.
www.OnBarcode.com
ECC200 Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
@Factory public Filter getChildrenFilterThroughNegativeQuery() { Term term = new Term( "childrenOnly", "yes" ); Query query = new TermQuery( term ); BooleanQuery totalQuery = new BooleanQuery();
PDF-417 2d Barcode Drawer In Java
Using Barcode generator for Java Control to generate, create PDF 417 image in Java applications.
www.OnBarcode.com
Quick Response Code Maker In Java
Using Barcode printer for Java Control to generate, create QR image in Java applications.
www.OnBarcode.com
Filters: cross-cutting restrictions
Barcode Creation In Java
Using Barcode creator for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
DataBar Creation In Java
Using Barcode encoder for Java Control to generate, create GS1 DataBar Truncated image in Java applications.
www.OnBarcode.com
totalQuery.add( new MatchAllDocsQuery(), Occur.SHOULD ); Add a term matching totalQuery.add( query, all documents Occur.MUST_NOT ); Filter filter = new QueryWrapperFilter( totalQuery ); return filter; }
UPC Symbol Creation In Java
Using Barcode generator for Java Control to generate, create UPC Symbol image in Java applications.
www.OnBarcode.com
USPS Confirm Service Barcode Maker In Java
Using Barcode generation for Java Control to generate, create USPS PLANET Barcode image in Java applications.
www.OnBarcode.com
Exclude elements matching a specific term
ECC200 Creator In None
Using Barcode drawer for Online Control to generate, create Data Matrix ECC200 image in Online applications.
www.OnBarcode.com
Recognizing Data Matrix 2d Barcode In C#
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Listing 8.9 must contain this somewhat artificial MatchAllDocsQuery. Otherwise the query results would be empty all the time because the negative term would be applied to nothing. The security example showed us how to explicitly add information into the index to later query on it or filter it. The procedure is quite simple:
Paint Barcode In None
Using Barcode printer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Decode ANSI/AIM Code 39 In VB.NET
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Write a bridge injecting the necessary information into the indexes. Apply the bridge to the relevant entity. Write a filter implementation (or a query) using the specific information stored in the index.
Generate PDF 417 In None
Using Barcode creation for Font Control to generate, create PDF-417 2d barcode image in Font applications.
www.OnBarcode.com
PDF417 Creation In Java
Using Barcode generation for Android Control to generate, create PDF-417 2d barcode image in Android applications.
www.OnBarcode.com
The next example shows you how to avoid getting the TooManyClauses exception when using a RangeQuery.
Encode UPC Code In Objective-C
Using Barcode drawer for iPad Control to generate, create Universal Product Code version A image in iPad applications.
www.OnBarcode.com
Data Matrix ECC200 Scanner In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Restricting results to a given range
Print Code 128 Code Set B In Visual Basic .NET
Using Barcode drawer for .NET framework Control to generate, create USS Code 128 image in .NET framework applications.
www.OnBarcode.com
Reading Code 128 In Visual Basic .NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Often a full-text query restricts one of the properties to a given range of values. For example:
UPC A Decoder In .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Drawing Barcode In Java
Using Barcode encoder for BIRT Control to generate, create Barcode image in Eclipse BIRT applications.
www.OnBarcode.com
Age must be between 20 and 30. Price must be lower than 500. Date must be between last month and today.
The classic approach for solving this problem is to use RangeQuery, as explained in section 7.3.6. Unfortunately, RangeQuery is susceptible to the TooManyClauses exception. When Lucene sees a RangeQuery, it replaces it with a series of TermQuerys. Lucene looks for all possible term values matching the range in the index for the targeted field and adds a term query for each of them. This approach is perfectly fine when the number of matching term values is relatively low, but it could quickly lead to TooManyClauses exceptions. An alternative approach is to use a range filter; the query is executed without range limitations. In the second phase, a filter removes the elements not matching the range. This approach no longer suffers from the TooManyClauses exception. This solution particularly shines in the following situations:
Term values matching the expected range are numerous. The same range is used many times across queries.
Examples of filter usage and their implementation
Our DVD store site has competitive prices and attracts people on a small budget. One of our features is to provide a search engine that targets prices below $15. The first step is to index prices using the padding technique described in chapter 4, and the second step is to create a filter implementation using RangeFilter. The bridge we used in section 4.1.3, (listing 4.6), suits our needs, and we ll reuse it. Listing 8.10 shows the filter implementation and its usage. Don t forget to apply the same logic applied by the price bridge to the value passed to the RangeFilter (in this case padding and rounding). The terms queried must match the terms indexed.
Listing 8.10 Price is indexed using a padding technique and rounding
@Entity @Indexed @Table(name="PRODUCTS") @FullTextFilterDef(name="maximumprice", impl=MaximumPriceFilterFactory.class) public class Item { @Column(name="PRICE") @NotNull @Digits(integerDigits=10, fractionalDigits=2) @Field(index=Index.UN_TOKENIZED) @FieldBridge( impl=ParameterizedPaddedRoundedPriceBridge.class, params= { @Parameter(name="pad", value="10"), @Parameter(name="round", value="1") } ) private BigDecimal price; ... } public class MaximumPriceFilterFactory { private static final int PAD = 10; private long maxPrice = -1; public void setMaxPrice(long maxPrice) { this.maxPrice = maxPrice; }
Pad numbers
Inject max price parameter
@Factory public Filter getMaximumPriceFilter() { if ( maxPrice == -1) { throw new IllegalStateException( "MaximumPriceFilterFactory.maxPrice is mandatory" ); Build a range filter } Filter filter = RangeFilter.Less( "price", pad( maxPrice ) ); return filter; }
@Key public FilterKey getKey() { StandardFilterKey key = new StandardFilterKey(); key.addParameter( maxPrice );
CHAPTER 8 return key; }
Filters: cross-cutting restrictions
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" );
Apply same padding as bridge
StringBuilder paddedLong = new StringBuilder(); for ( int padIndex = rawLong.length(); padIndex < PAD; padIndex++ ) { paddedLong.append( '0' ); } return paddedLong.append( rawLong ).toString(); } } public List<Item> searchItemsLowPrice(String search) { FullTextSession ftSession = SessionHolder.getFullTextSession(); org.apache.lucene.search.Query luceneQuery = buildLuceneQuery( search ); FullTextQuery query = ftSession.createFullTextQuery( luceneQuery, Item.class ); query.enableFullTextFilter( "maximumprice" ) .setParameter( "maxPrice", 15 ); @SuppressWarnings("unchecked") List<Item> results = query.list(); return results; }
Copyright © OnBarcode.com . All rights reserved.