Package org.apache.lucene.expressions.js
Class JavascriptCompiler
- java.lang.Object
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- org.apache.lucene.expressions.js.JavascriptCompiler
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public final class JavascriptCompiler extends Object
An expression compiler for javascript expressions.Example:
Expression foo = JavascriptCompiler.compile("((0.3*popularity)/10.0)+(0.7*score)");
See the
package documentation
for the supported syntax and default functions.You can compile with an alternate set of functions via
compile(String, Map, ClassLoader)
. For example:Map<String,Method> functions = new HashMap<>(); // add all the default functions functions.putAll(JavascriptCompiler.DEFAULT_FUNCTIONS); // add cbrt() functions.put("cbrt", Math.class.getMethod("cbrt", double.class)); // call compile with customized function map Expression foo = JavascriptCompiler.compile("cbrt(score)+ln(popularity)", functions, getClass().getClassLoader());
- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description static Map<String,Method>
DEFAULT_FUNCTIONS
The default set of functions available to expressions.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static Expression
compile(String sourceText)
Compiles the given expression.static Expression
compile(String sourceText, Map<String,Method> functions, ClassLoader parent)
Compiles the given expression with the supplied custom functions.
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Field Detail
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DEFAULT_FUNCTIONS
public static final Map<String,Method> DEFAULT_FUNCTIONS
The default set of functions available to expressions.See the
package documentation
for a list.
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Method Detail
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compile
public static Expression compile(String sourceText) throws ParseException
Compiles the given expression.- Parameters:
sourceText
- The expression to compile- Returns:
- A new compiled expression
- Throws:
ParseException
- on failure to compile
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compile
public static Expression compile(String sourceText, Map<String,Method> functions, ClassLoader parent) throws ParseException
Compiles the given expression with the supplied custom functions.Functions must be
public static
, returndouble
and can take from zero to 256double
parameters.- Parameters:
sourceText
- The expression to compilefunctions
- map of String names to functionsparent
- aClassLoader
that should be used as the parent of the loaded class. It must contain all classes referred to by the givenfunctions
.- Returns:
- A new compiled expression
- Throws:
ParseException
- on failure to compile
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