Class Lexer

java.lang.Object
org.datanucleus.store.query.compiler.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 ":".

  • Field Details

    • parameterPrefixes

      private final String parameterPrefixes
      Prefixes for any parameter, in a string. JDOQL will be ":". JPQL will be ":?".

    • input

      private final String input

    • ci

      protected final CharacterIterator ci

    • parseEscapedChars

      private final boolean parseEscapedChars

  • Constructor Details

    • 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 Details

    • 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

    • isDecDigit

      private static final boolean isDecDigit(char c)
      Utility to return if a character is a decimal digit.
      Parameters:
      c - The character
      Returns:
      Whether it is a decimal digit

    • isOctDigit

      private static final boolean isOctDigit(char c)
      Utility to return if a character is a octal digit.
      Parameters:
      c - The character
      Returns:
      Whether it is a octal digit

    • isHexDigit

      private static final boolean isHexDigit(char c)
      Utility to return if a character is a hexadecimal digit.
      Parameters:
      c - The character
      Returns:
      Whether it is a hexadecimal digit

    • 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

    • parseEscapedCharacter

      private char parseEscapedCharacter()
      Parse an escaped character.
      Returns:
      the escaped char
      Throws:
      NucleusUserException - if a escaped character is not valid

    • 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

    • toString

      public String toString()
      Overrides:
      toString in class Object