Package org.apache.commons.jexl3.parser

Class JexlParser

    • Field Detail

      • PRAGMA_OPTIONS

        public static final java.lang.String PRAGMA_OPTIONS
        The name of the options pragma.
        See Also:
        Constant Field Values

      • PRAGMA_JEXLNS

        public static final java.lang.String PRAGMA_JEXLNS
        The prefix of a namespace pragma.
        See Also:
        Constant Field Values

      • PRAGMA_MODULE

        public static final java.lang.String PRAGMA_MODULE
        The prefix of a module pragma.
        See Also:
        Constant Field Values

      • PRAGMA_IMPORT

        public static final java.lang.String PRAGMA_IMPORT
        The import pragma.
        See Also:
        Constant Field Values

      • ASSIGN_NODES

        private static final java.util.Set<java.lang.Class<? extends JexlNode>> ASSIGN_NODES
        The set of assignment operators as classes.

      • featureController

        protected final FeatureController featureController
        The associated controller.

      • info

        protected JexlInfo info
        The basic source info.

      • source

        protected java.lang.String source
        The source being processed.

      • scopeReference

        protected final java.util.concurrent.atomic.AtomicReference<Scope> scopeReference
        The map of named registers aka script parameters.

        Each parameter is associated with a register and is materialized as an offset in the registers array used during evaluation.

      • scopes

        protected final java.util.Deque<Scope> scopes
        When parsing inner functions/lambda, need to stack the scope (sic).

      • pragmas

        protected java.util.Map<java.lang.String,​java.lang.Object> pragmas
        The list of pragma declarations.

      • imports

        protected final java.util.List<java.lang.String> imports
        The list of imports.

        Imports are used to resolve simple class names into fully qualified class names.

      • autoSemicolon

        protected boolean autoSemicolon
        Whether automatic semicolon insertion is enabled.

      • namespaces

        protected java.util.Set<java.lang.String> namespaces
        The known namespaces.

      • loopCount

        protected java.util.concurrent.atomic.AtomicInteger loopCount
        The number of nested loops.

      • loopCounts

        protected final java.util.Deque<java.lang.Integer> loopCounts
        Stack of parsing loop counts.

      • blockReference

        protected final java.util.concurrent.atomic.AtomicReference<JexlParser.LexicalUnit> blockReference
        The current lexical block.

      • parent

        protected final JexlParser parent
        The parent parser if any.

      • NIL

        public static final java.lang.Object NIL
        The name of the null case constant.

      • DFLT

        public static final java.lang.Object DFLT
        The name of the default case constant.

      • NAN

        public static final java.lang.Object NAN
        The name of the default NaN constant.

    • Constructor Detail

      • JexlParser

        protected JexlParser()
        Creates a new parser.

        This constructor is protected so that it can only be used by subclasses.

      • JexlParser

        protected JexlParser​(JexlParser parser)
        Creates a new inner-parser.

        This is the constructor used to create a parser for template expressions.

    • Method Detail

      • errorToken

        protected static Token errorToken​(Token... tokens)
        Pick the most significant token for error reporting.
        Parameters:
        tokens - the tokens to choose from
        Returns:
        the token

      • readSourceLine

        protected static java.lang.String readSourceLine​(java.lang.String src,
                                                 int lineno)
        Reads a given source line.
        Parameters:
        src - the source
        lineno - the line number
        Returns:
        the line

      • stringify

        protected static java.lang.String stringify​(java.lang.Iterable<java.lang.String> lstr)
        Utility function to create '.' separated string from a list of string.
        Parameters:
        lstr - the list of strings
        Returns:
        the dotted version

      • addImport

        void addImport​(java.lang.String importName)

      • resolveConstant

        java.lang.Object resolveConstant​(java.lang.String name)

      • switchCode

        static java.lang.Object switchCode​(java.lang.Object value)
        Encode a value to a switch predicate.
        Parameters:
        value - the value.
        Returns:
        the encoded value, which is either the value itself, or NAN (for NaN) or NIL (for null).

      • switchSet

        protected JexlParser.SwitchSet switchSet()
        Constructs a set of constants amenable to switch expression.

      • allowRegisters

        public void allowRegisters​(boolean registers)
        Internal, for debug purpose only.
        Parameters:
        registers - sets whether this parser recognizes the register syntax

      • allowVariable

        protected boolean allowVariable​(java.lang.String image)
        Tests whether a given variable name is allowed.
        Parameters:
        image - the name.
        Returns:
        true if allowed, false if reserved.

      • checkLambda

        protected void checkLambda​(Token token)
        Check fat vs thin arrow syntax feature.
        Parameters:
        token - the arrow token.

      • checkVariable

        protected java.lang.String checkVariable​(ASTIdentifier identifier,
                                         java.lang.String name)
        Checks whether an identifier is a local variable or argument, ie a symbol, stored in a register.
        Parameters:
        identifier - the identifier.
        name - the identifier name.
        Returns:
        the image.

      • cleanup

        protected void cleanup​(JexlFeatures features)
        Cleanup.
        Parameters:
        features - the feature set to restore if any.

      • controlPragmaAnywhere

        protected void controlPragmaAnywhere()
        Disables pragma feature if pragma-anywhere feature is disabled.

      • declareFunction

        protected void declareFunction​(ASTVar variable,
                               Token token)
        Declares a local function.
        Parameters:
        variable - the identifier used to declare.
        token - the variable name token.

      • declareParameter

        protected void declareParameter​(Token token,
                                boolean lexical,
                                boolean constant)
        Declares a local parameter.

        This method creates a new entry in the symbol map.

        Parameters:
        token - the parameter name token.
        lexical - whether the parameter is lexical or not.
        constant - whether the parameter is constant or not.

      • declarePragma

        protected void declarePragma​(java.lang.String key,
                             java.lang.Object value)
        Adds a pragma declaration.
        Parameters:
        key - the pragma key.
        value - the pragma value.

      • declareSymbol

        private boolean declareSymbol​(int symbol)
        Declares a symbol.
        Parameters:
        symbol - the symbol index.
        Returns:
        true if symbol can be declared in lexical scope, false (error) if it is already declared.

      • declareVariable

        protected void declareVariable​(ASTVar variable,
                               Token token,
                               boolean lexical,
                               boolean constant)
        Declares a local variable.

        This method creates an new entry in the symbol map.

        Parameters:
        variable - the identifier used to declare.
        lexical - whether the symbol is lexical.
        constant - whether the symbol is constant.
        token - the variable name token.

      • getFeatures

        protected JexlFeatures getFeatures()
        Gets the current set of features active during parsing.
        Returns:
        the current set of features active during parsing.

      • getScope

        protected Scope getScope()
        Gets the frame used by this parser.

        Since local variables create new symbols, it is important to regain access after parsing to known which / how-many registers are needed.

        Returns:
        the named register map

      • getToken

        protected abstract Token getToken​(int index)
        Overridden in actual parser to access tokens stack.
        Parameters:
        index - 0 to get current token.
        Returns:
        the token on the stack.

      • getUnit

        protected JexlParser.LexicalUnit getUnit()
        Gets the lexical unit used by this parser.
        Returns:
        the named register map.

      • Identifier

        protected void Identifier​(boolean top)
                   throws ParseException
        Default implementation does nothing but is overridden by generated code.
        Parameters:
        top - whether the identifier is beginning an l/r value.
        Throws:
        ParseException - subclasses may throw ParseException.

      • isConstant

        private boolean isConstant​(int symbol)
        Checks whether a symbol has been declared as a const in the current stack of lexical units.
        Parameters:
        symbol - the symbol.
        Returns:
        true if constant, false otherwise.

      • isNamespace

        private boolean isNamespace​(java.lang.String name)
        Checks whether a name is a declared namespace.
        Parameters:
        name - the namespace name.
        Returns:
        true if declared, false otherwise.

      • isNamespaceFuncall

        protected boolean isNamespaceFuncall​(Token ns,
                                     Token colon,
                                     Token fun,
                                     Token paren)
        Semantic check identifying whether a list of 4 tokens forms a namespace function call.

        This is needed to disambiguate ternary operator, map entries and actual calls.

        Note that this check is performed before syntactic check so the expected parameters need to be verified.

        Parameters:
        ns - the namespace token.
        colon - expected to be ":"
        fun - the function name
        paren - expected to be "("
        Returns:
        true if the name qualifies a namespace function call.

      • isSymbolDeclared

        private boolean isSymbolDeclared​(JexlNode.Info info,
                                 int symbol)
        Checks if a symbol is defined in lexical scopes.

        This works with parsed scripts in template resolution only.

        Parameters:
        info - an info linked to a node.
        symbol - the symbol number.
        Returns:
        true if symbol accessible in lexical scope.

      • isVariable

        protected boolean isVariable​(java.lang.String name)
        Checks whether an identifier is a local variable or argument.
        Parameters:
        name - the variable name.
        Returns:
        true if a variable with that name was declared.

      • isAmbiguousStatement

        protected boolean isAmbiguousStatement​(int semicolon)
        Checks whether a statement is ambiguous.

        This is used to detect statements that are not terminated by a semicolon, and that may be confused with an expression.

        Parameters:
        semicolon - the semicolon token kind.
        Returns:
        true if statement is ambiguous, false otherwise.

      • jjtreeCloseNodeScope

        protected void jjtreeCloseNodeScope​(JexlNode node)
        Called by parser at end of node construction.

        Detects "Ambiguous statement" and 'non-left value assignment'.

        Parameters:
        node - the node.
        Throws:
        JexlException.Parsing - when parsing fails.

      • jxltParse

        public ASTJexlScript jxltParse​(JexlInfo info,
                               JexlFeatures features,
                               java.lang.String src,
                               Scope scope)
        Parses an embedded Jexl expression within an interpolation node.

        This creates a sub-parser that shares the scopes of the parent parser.

        Specified by:
        jxltParse in interface JexlScriptParser
        Parameters:
        info - the JexlInfo
        src - the source to parse
        features - the set of parsing features
        scope - the script frame
        Returns:
        the parsed tree

      • parseInterpolation

        static JxltEngine.Expression parseInterpolation​(JexlInfo info,
                                                java.lang.String src,
                                                Scope scope)
        Parses an interpolation expression.

        Requires the JEXL engine to be accessible through its thread-local.

        Parameters:
        info - the JexlInfo
        src - the source to parse
        scope - the scope
        Returns:
        the expression

      • jjtreeOpenNodeScope

        protected void jjtreeOpenNodeScope​(JexlNode node)
        Called by parser at the beginning of a node construction.
        Parameters:
        node - the node.

      • beginLambda

        protected void beginLambda​(ASTJexlScript jjtThis)
        Starts the definition of a lambda.
        Parameters:
        jjtThis - the script.

      • endLambda

        protected void endLambda​(ASTJexlScript jjtThis)
        Ends the definition of a lambda.
        Parameters:
        jjtThis - the script.

      • popScope

        protected void popScope()
        Pops back to previous local variable scope.

      • popUnit

        protected void popUnit​(JexlParser.LexicalUnit unit)
        Restores the previous lexical unit.
        Parameters:
        unit - restores the previous lexical scope.

      • pushScope

        protected void pushScope()
        Creates a new local variable scope and push it as current.

      • pushUnit

        protected void pushUnit​(JexlParser.LexicalUnit unit)
        Pushes a new lexical unit.
        Parameters:
        unit - the new lexical unit.

      • pushLoop

        protected void pushLoop()
        Escape any outer (parent) loops.

        A lambda definition embedded in a for-block escapes that block; break/continue are not valid within that lambda.

      • popLoop

        protected void popLoop()
        Restores the previous loop count.

      • setFeatures

        protected void setFeatures​(JexlFeatures features)
        Sets a new set of options.
        Parameters:
        features - the parser features

      • throwAmbiguousException

        protected void throwAmbiguousException​(JexlNode node)
        Throws Ambiguous exception.

        Seeks the end of the ambiguous statement to recover.

        Parameters:
        node - the first token in ambiguous expression.
        Throws:
        JexlException.Ambiguous - in all cases.

      • throwFeatureException

        protected void throwFeatureException​(int feature,
                                     JexlInfo info)
        Throws a feature exception.
        Parameters:
        feature - the feature code.
        info - the exception surroundings.
        Throws:
        JexlException.Feature - in all cases.

      • throwFeatureException

        protected void throwFeatureException​(int feature,
                                     Token trigger)
        Throws a feature exception.
        Parameters:
        feature - the feature code.
        trigger - the token that triggered it.
        Throws:
        JexlException.Parsing - if actual error token cannot be found.
        JexlException.Feature - in all other cases.

      • throwParsingException

        protected void throwParsingException​(Token parsed)
        Throws a parsing exception.
        Parameters:
        parsed - the token to report.
        Throws:
        JexlException.Parsing - in all cases.