Package org.apache.lucene.expressions.js

Class JavascriptCompiler

java.lang.Object

org.apache.lucene.expressions.js.JavascriptCompiler

public final class JavascriptCompiler
extends java.lang.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());
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	JavascriptCompiler.Loader

Field Summary

Fields

Modifier and Type	Field	Description
private static int	CLASSFILE_VERSION
private static java.lang.String	COMPILED_EXPRESSION_CLASS
private static java.lang.String	COMPILED_EXPRESSION_INTERNAL
static java.util.Map<java.lang.String,java.lang.reflect.Method>	DEFAULT_FUNCTIONS	The default set of functions available to expressions.
(package private) static org.objectweb.asm.commons.Method	DOUBLE_VAL_METHOD
private static org.objectweb.asm.commons.Method	EVALUATE_METHOD
private static org.objectweb.asm.commons.Method	EXPRESSION_CTOR
(package private) static org.objectweb.asm.Type	EXPRESSION_TYPE
(package private) static org.objectweb.asm.Type	FUNCTION_VALUES_TYPE
(package private) java.util.Map<java.lang.String,java.lang.reflect.Method>	functions
private static int	MAX_SOURCE_LENGTH
(package private) java.lang.String	sourceText

Constructor Summary

Constructors

Modifier	Constructor	Description
private	JavascriptCompiler(java.lang.String sourceText)	Constructs a compiler for expressions.
private	JavascriptCompiler(java.lang.String sourceText, java.util.Map<java.lang.String,java.lang.reflect.Method> functions)	Constructs a compiler for expressions with specific set of functions

Method Summary

Modifier and Type	Method	Description
private static void	checkFunction(java.lang.reflect.Method method)	Check Method signature for compatibility.
private static void	checkFunctionClassLoader(java.lang.reflect.Method method, java.lang.ClassLoader parent)	Cross check if declaring class of given method is the same as returned by the given parent ClassLoader on string lookup.
static Expression	compile(java.lang.String sourceText)	Compiles the given expression.
static Expression	compile(java.lang.String sourceText, java.util.Map<java.lang.String,java.lang.reflect.Method> functions, java.lang.ClassLoader parent)	Compiles the given expression with the supplied custom functions.
private Expression	compileExpression(java.lang.ClassLoader parent)	Compiles the given expression with the specified parent classloader
(package private) static int	findSingleQuoteStringEnd(java.lang.String text, int start)
private void	generateClass(org.antlr.v4.runtime.tree.ParseTree parseTree, org.objectweb.asm.ClassWriter classWriter, java.util.Map<java.lang.String,java.lang.Integer> externalsMap)	Sends the bytecode of class file to ClassWriter.
private org.antlr.v4.runtime.tree.ParseTree	getAntlrParseTree()	Parses the sourceText into an ANTLR 4 parse tree
private static org.objectweb.asm.commons.Method	getAsmMethod(java.lang.Class<?> rtype, java.lang.String name, java.lang.Class<?>... ptypes)	create an ASM Method object from return type, method name, and parameters.
(package private) static java.lang.String	normalizeQuotes(java.lang.String text)
private static void	unusedTestCompile()	This method is unused, it is just here to make sure that the function signatures don't change.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CLASSFILE_VERSION

private static final int CLASSFILE_VERSION

See Also:

Constant Field Values

COMPILED_EXPRESSION_CLASS

private static final java.lang.String COMPILED_EXPRESSION_CLASS

COMPILED_EXPRESSION_INTERNAL

private static final java.lang.String COMPILED_EXPRESSION_INTERNAL

EXPRESSION_TYPE

static final org.objectweb.asm.Type EXPRESSION_TYPE

FUNCTION_VALUES_TYPE

static final org.objectweb.asm.Type FUNCTION_VALUES_TYPE

EXPRESSION_CTOR

private static final org.objectweb.asm.commons.Method EXPRESSION_CTOR

EVALUATE_METHOD

private static final org.objectweb.asm.commons.Method EVALUATE_METHOD

DOUBLE_VAL_METHOD

static final org.objectweb.asm.commons.Method DOUBLE_VAL_METHOD

MAX_SOURCE_LENGTH

private static final int MAX_SOURCE_LENGTH

See Also:

Constant Field Values

sourceText

final java.lang.String sourceText

functions

final java.util.Map<java.lang.String,java.lang.reflect.Method> functions

DEFAULT_FUNCTIONS

public static final java.util.Map<java.lang.String,java.lang.reflect.Method> DEFAULT_FUNCTIONS

The default set of functions available to expressions.

See the package documentation for a list.

Constructor Detail

JavascriptCompiler

private JavascriptCompiler(java.lang.String sourceText)

Constructs a compiler for expressions.

Parameters:

sourceText - The expression to compile

JavascriptCompiler

private JavascriptCompiler(java.lang.String sourceText,
                           java.util.Map<java.lang.String,java.lang.reflect.Method> functions)

Constructs a compiler for expressions with specific set of functions

Parameters:

sourceText - The expression to compile

Method Detail

getAsmMethod

private static org.objectweb.asm.commons.Method getAsmMethod(java.lang.Class<?> rtype,
                                                             java.lang.String name,
                                                             java.lang.Class<?>... ptypes)

create an ASM Method object from return type, method name, and parameters.

compile

public static Expression compile(java.lang.String sourceText)
                          throws java.text.ParseException

Compiles the given expression.

Parameters:

sourceText - The expression to compile

Returns:

A new compiled expression

Throws:

java.text.ParseException - on failure to compile

compile

public static Expression compile(java.lang.String sourceText,
                                 java.util.Map<java.lang.String,java.lang.reflect.Method> functions,
                                 java.lang.ClassLoader parent)
                          throws java.text.ParseException

Compiles the given expression with the supplied custom functions.

Functions must be public static, return double and can take from zero to 256 double parameters.

Parameters:

sourceText - The expression to compile

functions - map of String names to functions

parent - a ClassLoader that should be used as the parent of the loaded class. It must contain all classes referred to by the given functions.

Returns:

A new compiled expression

Throws:

java.text.ParseException - on failure to compile

unusedTestCompile

private static void unusedTestCompile()
                               throws java.io.IOException

This method is unused, it is just here to make sure that the function signatures don't change. If this method fails to compile, you also have to change the byte code generator to correctly use the FunctionValues class.

Throws:

java.io.IOException

compileExpression

private Expression compileExpression(java.lang.ClassLoader parent)
                              throws java.text.ParseException

Compiles the given expression with the specified parent classloader

Returns:

A new compiled expression

Throws:

java.text.ParseException - on failure to compile

getAntlrParseTree

private org.antlr.v4.runtime.tree.ParseTree getAntlrParseTree()
                                                       throws java.text.ParseException

Parses the sourceText into an ANTLR 4 parse tree

Returns:

The ANTLR parse tree

Throws:

java.text.ParseException - on failure to parse

generateClass

private void generateClass(org.antlr.v4.runtime.tree.ParseTree parseTree,
                           org.objectweb.asm.ClassWriter classWriter,
                           java.util.Map<java.lang.String,java.lang.Integer> externalsMap)
                    throws java.text.ParseException

Sends the bytecode of class file to ClassWriter.

Throws:

java.text.ParseException

normalizeQuotes

static java.lang.String normalizeQuotes(java.lang.String text)

findSingleQuoteStringEnd

static int findSingleQuoteStringEnd(java.lang.String text,
                                    int start)

checkFunction

private static void checkFunction(java.lang.reflect.Method method)

Check Method signature for compatibility.

checkFunctionClassLoader

private static void checkFunctionClassLoader(java.lang.reflect.Method method,
                                             java.lang.ClassLoader parent)

Cross check if declaring class of given method is the same as returned by the given parent ClassLoader on string lookup. This prevents NoClassDefFoundError.