Apache
/
lucene
mirror of https://github.com/apache/lucene.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add a reference to FunctionScoreQuery to javadocs of Expression.

This commit is contained in:
Adrien Grand 2017-03-01 17:20:08 +01:00
parent 010bffecf9
commit 1cfa048643
1 changed files with 21 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
lucene/expressions/src/java/org/apache/lucene/expressions/Expression.java
View File

@ -25,20 +25,38 @@ import org.apache.lucene.search.SortField;
/**
* Base class that computes the value of an expression for a document.
* <p>
* Example usage:
* Example that sorts based on an expression:
* <pre class="prettyprint">
* // compile an expression:
* Expression expr = JavascriptCompiler.compile("sqrt(_score) + ln(popularity)");
*
* // SimpleBindings just maps variables to SortField instances
* SimpleBindings bindings = new SimpleBindings();
* SimpleBindings bindings = new SimpleBindings();
* bindings.add(new SortField("_score", SortField.Type.SCORE));
* bindings.add(new SortField("popularity", SortField.Type.INT));
*
* // create a sort field and sort by it (reverse order)
* Sort sort = new Sort(expr.getSortField(bindings, true));
* Query query = new TermQuery(new Term("body", "contents"));
* searcher.search(query, null, 10, sort);
* searcher.search(query, 10, sort);
* </pre>
* <p>
* Example that modifies the scores produced by the query:
* <pre class="prettyprint">
* // compile an expression:
* Expression expr = JavascriptCompiler.compile("sqrt(_score) + ln(popularity)");
*
* // SimpleBindings just maps variables to SortField instances
* SimpleBindings bindings = new SimpleBindings();
* bindings.add(new SortField("_score", SortField.Type.SCORE));
* bindings.add(new SortField("popularity", SortField.Type.INT));
*
* // create a query that matches based on body:contents but
* // scores using expr
* Query query = new FunctionScoreQuery(
* new TermQuery(new Term("body", "contents")),
* expr.getDoubleValuesSource(bindings));
* searcher.search(query, 10);
* </pre>
* @see JavascriptCompiler#compile
* @lucene.experimental