Package org.eclipse.persistence.jpa.jpql

Class WordParser

java.lang.Object
org.eclipse.persistence.jpa.jpql.WordParser
public final class WordParser extends Object
This "parser/scanner" holds onto the string version of the JPQL query that is parsed into a parsed tree. It uses a cursor that lets the current Expression object to parse its fragment of the query.

Provisional API: This interface is part of an interim API that is still under development and expected to change significantly before reaching stability. It is available at this early stage to solicit feedback from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken (repeatedly) as the API evolves.

Version:
2.5.1
Author:
Pascal Filion

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static enum 
    WordParser.WordType
    This enumeration determines the type of word that was scanned.

  • Constructor Summary

    Constructors
    Constructor
    Description
    WordParser(CharSequence text)
    Creates a new WordParser.

  • Method Summary

    Modifier and Type
    Method
    Description
    char
    character()
    Retrieves the character at the current cursor position.
    char
    character(int position)
    Retrieves the character at the given cursor position.
    boolean
    endsWith(int endPosition, String suffix)
    Determines whether the query ends with the given suffix and the end position is the end of the range for testing.
    boolean
    endsWithIgnoreCase(int endPosition, String suffix)
    Determines whether the query ends with the given suffix and the end position is the end of the range for testing.
    String
    entireWord()
    Retrieves a word starting at the current position.
    String
    entireWord(int position)
    Retrieves a word starting at the given position.
    WordParser.WordType
    getWordType()
    Returns what the type of word word() returns.
    boolean
    isArithmeticSymbol(char character)
    Determines whether the given character is an arithmetic symbol, which is one of the following: { '>', '<', '/', '*', '-', '+', '=', '{'} .
    boolean
    isDelimiter(char character)
    Determines whether the given character is a delimiter.
    boolean
    isDigit(char character)
    Determines whether the given character is a character that can be used in a number.
    boolean
    isTail()
    Determines whether the position of the cursor is at the end of the text.
    boolean
    isWordSeparator(char character)
    Determines whether the given character is not considered to be part of a word (which is usually comprise of alphanumeric characters).
    int
    length()
    Returns the length of the string value.
    void
    moveBackward(int position)
    Moves backward the position of the cursor by the given amount.
    void
    moveBackward(CharSequence word)
    Moves the position of the cursor by the length of the given word.
    String
    moveForward(int position)
    Moves forward the position of the cursor by the given amount.
    String
    moveForward(CharSequence word)
    Moves the position of the cursor by the length of the given word.
    String
    moveForwardIgnoreWhitespace(CharSequence word)
    Moves the position of the cursor by the length of the given word and ignore any different in whitespace count.
    String
    numericLiteral()
    Retrieves the numeric literal that should be the current word to parse.
    String
    partialWord()
    Retrieves a word before the current position of the cursor, which determines when the parsing stop.
    String
    partialWord(int position)
    Retrieves a word before the specified position, which determines when the parsing stop.
    int
    partialWordStartPosition(int position)
    Finds the beginning of the word and the given position is within that word.
    int
    position()
    Returns the current position of the cursor.
    void
    setPosition(int position)
    Manually sets the position of the cursor within the string.
    int
    skipLeadingWhitespace()
    Removes the whitespace that starts the given text.
    boolean
    startsWith(char possibleCharacter)
    Determines whether the text starts with the given character.
    boolean
    startsWith(CharSequence prefix)
    Tests whether the query starts with the specified prefix from the current position.
    boolean
    startsWith(CharSequence prefix, int startIndex)
    Tests whether the substring of the query beginning at the specified index starts with the specified prefix.
    boolean
    startsWithArithmeticOperator()
    Determines whether the character at the current position is one of the arithmetic operators: { '+', '-', '*', '/' },
    Boolean
    startsWithDigit()
    Determines if the text starts with a digit (true), an arithmetic term (false) or anything else (null).
    boolean
    startsWithIdentifier(CharSequence identifier)
    Determines whether the text at the current position start with the following identifier.
    boolean
    startsWithIdentifier(CharSequence identifier, int position)
    Determines whether the text at the current position start with the following identifier.
    boolean
    startsWithIgnoreCase(char possibleCharacter)
    Determines whether the text starts with the given character.
    boolean
    startsWithIgnoreCase(CharSequence prefix)
    Tests if the string starts with the specified prefix.
    boolean
    startsWithIgnoreCase(CharSequence prefix, int offset)
    Tests if the string starts with the specified prefix.
    String
    substring()
    Returns a substring that is within the current position of the cursor and the end of the text.
    String
    substring(int startIndex)
    Returns a substring that is within the given position and the end of the text.
    String
    substring(int startIndex, int endIndex)
    Returns a substring that is within the given positions.
    String
    toString()
     
    int
    whitespaceCount()
    Calculates the number of whitespace that are in the query.
    int
    whitespaceCount(int position)
    Calculates the number of whitespace that are in the query.
    String
    word()
    Retrieves the first word starting at the current position.
    int
    wordEndPosition()
    Returns the position a word would end based on the current cursor position.
    int
    wordEndPosition(int position)
    Returns the position a word would end based on the given start position.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • WordParser

      public WordParser(CharSequence text)
      Creates a new WordParser.
      Parameters:
      text - The string representation of the JPQL query

  • Method Details

    • character

      public char character()
      Retrieves the character at the current cursor position.
      Returns:
      The character retrieved from the string at the current cursor position or '\0' if the position is beyond the end of the text

    • character

      public char character(int position)
      Retrieves the character at the given cursor position.
      Parameters:
      position - The position of the character to return
      Returns:
      The character retrieved from the string at the given position or '\0' if the position is beyond the end of the text

    • endsWith

      public boolean endsWith(int endPosition, String suffix)
      Determines whether the query ends with the given suffix and the end position is the end of the range for testing.
      Parameters:
      endPosition - The position where the check stops
      suffix - The suffix is the text that is used to match it with the substring within the text
      Returns:
      true if the character sequence represented by the argument is a suffix of the query; false otherwise

    • endsWithIgnoreCase

      public boolean endsWithIgnoreCase(int endPosition, String suffix)
      Determines whether the query ends with the given suffix and the end position is the end of the range for testing. The case of the character is ignored.
      Parameters:
      endPosition - The position where the check stops
      suffix - The suffix is the text that is used to match it with the substring within the text
      Returns:
      true if the character sequence represented by the argument is a suffix of the query; false otherwise

    • entireWord

      public String entireWord()
      Retrieves a word starting at the current position. The text before and after the position will be part of the returned value.

      For instance, "SELECT AVG(e.age) FROM Employee e":

      • Position 3, result is "SELECT";
      • Position 6, result is "SELECT";
      • Position 7, result is an empty string.
      • Position 11, result is an empty string.
      • Position 13, result is "e.".
      Returns:
      The word in which the cursor is

    • entireWord

      public String entireWord(int position)
      Retrieves a word starting at the given position. The text before and after the position will be part of the returned value.

      For instance, "SELECT AVG(e.age) FROM Employee e":

      • Position 3, result is "SELECT";
      • Position 6, result is "SELECT";
      • Position 7, result is an empty string.
      • Position 11, result is an empty string.
      • Position 13, result is "e.".
      Parameters:
      position - The position where to retrieve the word
      Returns:
      The word in which the cursor is

    • getWordType

      public WordParser.WordType getWordType()
      Returns what the type of word word() returns.
      Returns:
      The category of the word returned by word()

    • isArithmeticSymbol

      public boolean isArithmeticSymbol(char character)
      Determines whether the given character is an arithmetic symbol, which is one of the following: { '>', '<', '/', '*', '-', '+', '=', '{'} .
      Parameters:
      character - The character to test if it's a math symbol
      Returns:
      true if the given character is one of the valid math symbols; false otherwise

    • isDelimiter

      public boolean isDelimiter(char character)
      Determines whether the given character is a delimiter. The delimiter are '(', ')' and ','.
      Parameters:
      character - The character to test
      Returns:
      true if the given character is a delimiter; false otherwise

    • isDigit

      public boolean isDigit(char character)
      Determines whether the given character is a character that can be used in a number. This only includes the numeric characters [0, 9] and the period character. This method should only be used to determine if a word starts with a digit character.
      Parameters:
      character - The character to test if it's a digit
      Returns:
      true if the given character is a digit; false otherwise

    • isTail

      public boolean isTail()
      Determines whether the position of the cursor is at the end of the text.
      Returns:
      true if the position of the cursor is at the end of the text; false otherwise

    • isWordSeparator

      public boolean isWordSeparator(char character)
      Determines whether the given character is not considered to be part of a word (which is usually comprise of alphanumeric characters).
      Parameters:
      character - The character used to determine if it should be part of a word or not
      Returns:
      true if the character can be part of a word; false if it is not an alphanumeric character, which usually means is a whitespace, a delimiter or an arithmetic symbol
      See Also:

    • length

      public int length()
      Returns the length of the string value.
      Returns:
      The total count of characters

    • moveBackward

      public void moveBackward(CharSequence word)
      Moves the position of the cursor by the length of the given word.
      Parameters:
      word - The word used to determine how much to move the position forward

    • moveBackward

      public void moveBackward(int position)
      Moves backward the position of the cursor by the given amount.
      Parameters:
      position - The amount to remove from the current position

    • moveForward

      public String moveForward(CharSequence word)
      Moves the position of the cursor by the length of the given word.
      Parameters:
      word - The word used to determine how much to move the position forward
      Returns:
      The actual portion of the text that was skipped

    • moveForward

      public String moveForward(int position)
      Moves forward the position of the cursor by the given amount.
      Parameters:
      position - The amount to add to the current position
      Returns:
      The actual portion of the text that was skipped

    • moveForwardIgnoreWhitespace

      public String moveForwardIgnoreWhitespace(CharSequence word)
      Moves the position of the cursor by the length of the given word and ignore any different in whitespace count. If the text has more than one whitespace and the given word usually has one, then only one will be part of the returned substring.
      Parameters:
      word - The word used to determine how much to move the position forward
      Returns:
      The actual portion of the text that was skipped

    • numericLiteral

      public String numericLiteral()
      Retrieves the numeric literal that should be the current word to parse.
      Returns:
      The numeric literal value

    • partialWord

      public String partialWord()
      Retrieves a word before the current position of the cursor, which determines when the parsing stop.

      For instance, "SELECT AVG(e.age) FROM Employee e":

      • Position 3, result is "SEL";
      • Position 6, result is "SELECT";
      • Position 7, result is an empty string.
      • Position 11, result is an empty string.
      • Position 13, result is "e.".
      Returns:
      The sub-string that is before the position

    • partialWord

      public String partialWord(int position)
      Retrieves a word before the specified position, which determines when the parsing stop.

      For instance, "SELECT AVG(e.age) FROM Employee e":

      • Position 3, result is "SEL";
      • Position 6, result is "SELECT";
      • Position 7, result is an empty string.
      • Position 11, result is an empty string.
      • Position 13, result is "e.".
      Parameters:
      position - The position of the cursor
      Returns:
      The sub-string that is before the position

    • partialWordStartPosition

      public int partialWordStartPosition(int position)
      Finds the beginning of the word and the given position is within that word.

      For instance, "SELECT AVG(e.age) FROM Employee e":

      • Position 3, result is 0;
      • Position 8, result is 7;
      Parameters:
      position - The position from which the search ends
      Returns:
      The position, which is a smaller number or equal, than the given position

    • position

      public int position()
      Returns the current position of the cursor.
      Returns:
      The current position of the cursor

    • setPosition

      public void setPosition(int position)
      Manually sets the position of the cursor within the string. If the position is a negative number, the position will be 0.
      Parameters:
      position - The new position of the cursor

    • skipLeadingWhitespace

      public int skipLeadingWhitespace()
      Removes the whitespace that starts the given text.
      Returns:
      The number of whitespace removed

    • startsWith

      public boolean startsWith(char possibleCharacter)
      Determines whether the text starts with the given character. The case of the character is not ignored.
      Parameters:
      possibleCharacter - The possible character at the current position
      Returns:
      true if the text starts with the given character at the current position; false otherwise

    • startsWith

      public boolean startsWith(CharSequence prefix)
      Tests whether the query starts with the specified prefix from the current position.
      Parameters:
      prefix - The prefix
      Returns:
      true if the character sequence represented by the argument is a prefix of the text; false otherwise

    • startsWith

      public boolean startsWith(CharSequence prefix, int startIndex)
      Tests whether the substring of the query beginning at the specified index starts with the specified prefix.
      Parameters:
      prefix - The prefix
      startIndex - Where to begin looking in the query
      Returns:
      true if the character sequence represented by the argument is a prefix of the substring of this object starting at index startIndex; false otherwise

    • startsWithArithmeticOperator

      public boolean startsWithArithmeticOperator()
      Determines whether the character at the current position is one of the arithmetic operators: { '+', '-', '*', '/' },
      Returns:
      true if the character at the current position is an arithmetic operator; false otherwise

    • startsWithDigit

      public Boolean startsWithDigit()
      Determines if the text starts with a digit (true), an arithmetic term (false) or anything else (null).
      Returns:
      true if the text starts with a digit (we'll assume it is a digit if the text starts with a digit or an arithmetic sign followed by a digit), false if it starts with an arithmetic term (we'll assume it is a digit followed by a non-digit character); otherwise returns null

    • startsWithIdentifier

      public boolean startsWithIdentifier(CharSequence identifier)
      Determines whether the text at the current position start with the following identifier.
      Parameters:
      identifier - The JPQL identifier to match with the text at the current position
      Returns:
      true if the text starts with the given text (case is ignored) and the cursor is at the end of the text or is following by a word separator character; false otherwise

    • startsWithIdentifier

      public boolean startsWithIdentifier(CharSequence identifier, int position)
      Determines whether the text at the current position start with the following identifier.
      Parameters:
      identifier - The JPQL identifier to match with the text at the current position
      position - The position to start matching the characters
      Returns:
      true if the text starts with the given text (case is ignored) and the cursor is at the end of the text or is following by a word separator character; false otherwise

    • startsWithIgnoreCase

      public boolean startsWithIgnoreCase(char possibleCharacter)
      Determines whether the text starts with the given character. The case of the character is ignored.
      Parameters:
      possibleCharacter - The possible character at the current position
      Returns:
      true if the text starts with the given character at the current position; false otherwise

    • startsWithIgnoreCase

      public boolean startsWithIgnoreCase(CharSequence prefix)
      Tests if the string starts with the specified prefix. The case of the character is ignored.
      Parameters:
      prefix - The prefix to test against
      Returns:
      true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise. Note also that true will be returned if the argument is an empty string or is equal to this String object as determined by the Object.equals(Object) method

    • startsWithIgnoreCase

      public boolean startsWithIgnoreCase(CharSequence prefix, int offset)
      Tests if the string starts with the specified prefix. The case of the character is ignored.
      Parameters:
      prefix - The prefix to test against
      offset - Where to begin looking in this string
      Returns:
      true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise

    • substring

      public String substring()
      Returns a substring that is within the current position of the cursor and the end of the text.
      Returns:
      The remain of the string starting at the current position

    • substring

      public String substring(int startIndex)
      Returns a substring that is within the given position and the end of the text.
      Parameters:
      startIndex - The beginning of the substring, inclusive
      Returns:
      The remain of the string starting at the given position

    • substring

      public String substring(int startIndex, int endIndex)
      Returns a substring that is within the given positions.
      Parameters:
      startIndex - The beginning of the substring, inclusive
      endIndex - The end of the substring, exclusive
      Returns:
      The remain of the string that is within the given positions

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • whitespaceCount

      public int whitespaceCount()
      Calculates the number of whitespace that are in the query. The check starts at the current position.
      Returns:
      The count of consecutive whitespace found from the current position

    • whitespaceCount

      public int whitespaceCount(int position)
      Calculates the number of whitespace that are in the query. The check starts at the current position.
      Parameters:
      position - The position from where the scan starts
      Returns:
      The count of consecutive whitespace found from the given position

    • word

      public String word()
      Retrieves the first word starting at the current position.
      Returns:
      The first word contained in the text, if none could be found, then an empty string is returned

    • wordEndPosition

      public int wordEndPosition()
      Returns the position a word would end based on the current cursor position. getWordType() can be used to determine the type of word that was scanned.
      Returns:
      The position where the current word ends
      See Also:

    • wordEndPosition

      public int wordEndPosition(int position)
      Returns the position a word would end based on the given start position. getWordType() can be used to determine the type of word that was scanned.
      Parameters:
      position - The position to start scanning the text
      Returns:
      The position where the current word ends
      See Also: