Package org.datanucleus.store.query.compiler

Class Lexer

  • public class Lexer
extends Object
    Lexer for a Query. Allows a class to work its way through the parsed string, obtaining relevant components with each call, or peeking ahead before deciding what component to parse next. Would work with JDOQL or JPQL, the only difference being the input of parameter prefixes. With JDOQL all parameters are prefixed ":", whereas in JPQL you can have numbered parameters "?" and named parameters ":".

    • Constructor Detail

      • Lexer

        public Lexer​(String input,
             String paramPrefixes,
             boolean parseEscapedChars)
        Constructor
        Parameters:
        input - The input string
        paramPrefixes - String containing all possible prefixes for parameters
        parseEscapedChars - Whether to prase escaped characters

    • Method Detail

      • getInput

        public String getInput()
        Accessor for the input string.
        Returns:
        The input string.

      • getIndex

        public int getIndex()
        Accessor for the current index in the input string.
        Returns:
        The current index.

      • setIndex

        public void setIndex​(int idx)

      • skipWS

        public int skipWS()
        Skip over any whitespace from the current position.
        Returns:
        The new position

      • parseEOS

        public boolean parseEOS()
        Check if END OF TEXT is reached.
        Returns:
        true if END OF TEXT is reached

      • parseChar

        public boolean parseChar​(char c)
        Check if char c is found
        Parameters:
        c - the Character to find
        Returns:
        true if c is found

      • parseChar

        public boolean parseChar​(char c,
                         char unlessFollowedBy)
        Check if char c is found
        Parameters:
        c - the Character to find
        unlessFollowedBy - the character to validate it does not follow c
        Returns:
        true if c is found and not followed by unlessFollowedBy

      • parseString

        public boolean parseString​(String s)
        Check if String s is found
        Parameters:
        s - the String to find
        Returns:
        true if s is found

      • parseStringIgnoreCase

        public boolean parseStringIgnoreCase​(String s)
        Check if String s is found ignoring the case
        Parameters:
        s - the String to find
        Returns:
        true if s is found

      • peekString

        public boolean peekString​(String s)
        Check if String "s" is found and not moving the cursor position.
        Parameters:
        s - the String to find
        Returns:
        true if string is found

      • peekStringIgnoreCase

        public boolean peekStringIgnoreCase​(String s)
        Check if String "s" is found ignoring the case, and not moving the cursor position.
        Parameters:
        s - the String to find
        Returns:
        true if string is found

      • parseIdentifier

        public String parseIdentifier()
        Parse a java identifier from the current position.
        Returns:
        The identifier

      • parseMethod

        public String parseMethod()
        Checks if a java Method is found
        Returns:
        true if a Method is found

      • parseName

        public String parseName()
        Parses the text string (up to the next space) and returns it. The name includes '.' characters. This can be used, for example, when parsing a class name wanting to read in the full name (including package) so that it can then be checked for existence in the CLASSPATH.
        Returns:
        The name

      • parseCast

        public String parseCast()
        Parse a cast in the query from the current position, returning the name of the class that is being cast to. Returns null if the current position doesn't have a cast. Does no checking as to whether the name is a valid class name, just whether there is "({name})" from the current position.
        Returns:
        The name of the class to cast to

      • parseIntegerLiteral

        public Number parseIntegerLiteral()
        Parse an integer number from the current position.
        Returns:
        The integer number parsed (null if not valid).

      • parseFloatingPointLiteral

        public Number parseFloatingPointLiteral()
        Parse a floating point number from the current position.
        Returns:
        The floating point number parsed (null if not valid).

      • parseBooleanLiteral

        public Boolean parseBooleanLiteral()
        Parse a boolean from the current position.
        Returns:
        The boolean parsed (null if not valid).

      • parseBooleanLiteralIgnoreCase

        public Boolean parseBooleanLiteralIgnoreCase()
        Parse a boolean from the current position (case insensitive).
        Returns:
        The boolean parsed (null if not valid).

      • nextIsSingleQuote

        public boolean nextIsSingleQuote()
        Utility to return if the next non-whitespace character is a single quote.
        Returns:
        Whether it is a single quote at the current point (ignoring whitespace)

      • nextIsDot

        public boolean nextIsDot()
        Utility to return if the next character is a dot.
        Returns:
        Whether it is a dot at the current point

      • parseCharacterLiteral

        public Character parseCharacterLiteral()
        Parse a Character literal
        Returns:
        the Character parsed. null if single quotes is found
        Throws:
        NucleusUserException - if an invalid character is found or the CharacterIterator is finished

      • parseStringLiteral

        public String parseStringLiteral()
        Parse a String literal
        Returns:
        the String parsed. null if single quotes or double quotes is found
        Throws:
        NucleusUserException - if an invalid character is found or the CharacterIterator is finished

      • parseNullLiteral

        public boolean parseNullLiteral()
        Checks if null literal is parsed
        Returns:
        true if null literal is found

      • parseNullLiteralIgnoreCase

        public boolean parseNullLiteralIgnoreCase()
        Checks if null literal is parsed (case insensitive).
        Returns:
        true if null literal is found

      • remaining

        public String remaining()
        Method to return the remaining part of the string not yet processed. Doesn't move the current position.
        Returns:
        The remaining part of the string