Package org.eclipse.persistence.jpa.jpql

Class ExpressionTools

java.lang.Object
org.eclipse.persistence.jpa.jpql.ExpressionTools
public final class ExpressionTools extends Object
A utility class containing various methods related to the Hermes parser.

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:
2.6
Author:
Pascal Filion

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final Pattern
    DOUBLE_REGEXP
    The Pattern representing the regular expression of a numerical value as a double.
    static final Object[]
    EMPTY_ARRAY
    The constant of an empty array.
    static final String
    EMPTY_STRING
    The constant for an empty string.
    static final String[]
    EMPTY_STRING_ARRAY
    The constant of an empty String array.
    static final Pattern
    FLOAT_REGEXP
    The Pattern representing the regular expression of a numerical value as a float.
    static final Pattern
    INTEGER_REGEXP
    The Pattern representing the regular expression of a numerical value as an integer.
    static final Pattern
    LONG_REGEXP
    The Pattern representing the regular expression of a numerical value as a long.

  • Method Summary

    Modifier and Type
    Method
    Description
    static String
    escape(CharSequence value, int[] position)
    Converts the escape characters contained in the given CharSequence to their literal representation.
    static boolean
    isFunctionExpression(WordParser wordParser, String identifier)
    Determines whether the JPQL fragment is an expression of the form <IDENTIFIER>(.
    static boolean
    isJavaEscapedCharacter(char character)
    Determines whether the given character should be escaped when being part of a string, i.e.
    static boolean
    isParameter(char character)
    Determines whether the given character is the character used to identify an input parameter, either a named parameter or position parameter.
    static boolean
    isQuote(char character)
    Determines whether the given character is the single or double quote.
    static boolean
    isWhiteSpace(char character)
    Determines whether the given character is whitespace.
    static String
    quote(String text)
    Returns the given string literal by wrapping it with single quotes.
    static void
    reposition(CharSequence query1, int[] positions, CharSequence query2)
    Adjusts the positions contained by the given array of either one or two elements, which is based on the given query1, by translating those positions to be at the equivalent position within query2.
    static int
    repositionCursor(CharSequence query1, int position1, CharSequence query2)
    Adjusts the position, which is based on the given query1, by translating it to be at the equivalent position within query2.
    static void
    repositionJava(CharSequence query, int[] positions)
    Re-adjusts the given positions, which is based on the non-escaped version of the given query, by making sure it is pointing at the same position within query, which contains references (escape characters).
    static boolean
    startWithIgnoreCase(String string, String prefix)
    Determines whether the given string starts with the given prefix and ignores the case.
    static boolean
    stringIsEmpty(CharSequence text)
    Determines whether the specified string is null, empty, or contains only whitespace characters.
    static boolean
    stringIsNotEmpty(CharSequence text)
    Determines whether the specified string is NOT null, NOT empty, or contains at least one non-whitespace character.
    static boolean
    stringsAreDifferentIgnoreCase(CharSequence value1, CharSequence value2)
    Determines whether the two sequence of characters are different, with the appropriate null checks and the case is ignored.
    static boolean
    stringsAreEqualIgnoreCase(CharSequence value1, CharSequence value2)
    Determines whether the two sequence of characters are equal or equivalent, with the appropriate null checks and the case is ignored.
    static String
    unescape(CharSequence value, int[] position)
    Converts the string representation of the escape characters contained by the given CharSequence into the actual escape characters.
    static String
    unquote(String text)
    Returns the string literal without the single or double quotes.
    static boolean
    valuesAreDifferent(Object value1, Object value2)
    Determines whether the values are different, with the appropriate null checks.
    static boolean
    valuesAreEqual(Object value1, Object value2)
    Determines whether the values are equal or equivalent, with the appropriate null checks.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • DOUBLE_REGEXP

      public static final Pattern DOUBLE_REGEXP
      The Pattern representing the regular expression of a numerical value as a double.

    • EMPTY_ARRAY

      public static final Object[] EMPTY_ARRAY
      The constant of an empty array.

    • EMPTY_STRING

      public static final String EMPTY_STRING
      The constant for an empty string.
      See Also:

    • EMPTY_STRING_ARRAY

      public static final String[] EMPTY_STRING_ARRAY
      The constant of an empty String array.

    • FLOAT_REGEXP

      public static final Pattern FLOAT_REGEXP
      The Pattern representing the regular expression of a numerical value as a float.

    • INTEGER_REGEXP

      public static final Pattern INTEGER_REGEXP
      The Pattern representing the regular expression of a numerical value as an integer.

    • LONG_REGEXP

      public static final Pattern LONG_REGEXP
      The Pattern representing the regular expression of a numerical value as a long.

  • Method Details

    • escape

      public static String escape(CharSequence value, int[] position)
      Converts the escape characters contained in the given CharSequence to their literal representation. For example, '\b' is converted to '\\b'.
      Parameters:
      value - The sequence of characters to convert any escape character
      position - This is a one element array that needs to be adjusted when an escape character is converted
      Returns:
      The new sequence of characters that does not contain any escape character but it's literal representation

    • isFunctionExpression

      public static boolean isFunctionExpression(WordParser wordParser, String identifier)
      Determines whether the JPQL fragment is an expression of the form <IDENTIFIER>(.
      Parameters:
      wordParser - The text to parse based on the current position of the cursor
      identifier - The identifier to verify if it's for an expression or for possibly for a variable name
      Returns:
      true if the identifier is followed by '('; false otherwise

    • isJavaEscapedCharacter

      public static boolean isJavaEscapedCharacter(char character)
      Determines whether the given character should be escaped when being part of a string, i.e. '\r' should be "\\r".
      Parameters:
      character - The character to check if it can directly be used in a string or should be escaped
      Returns:
      true if the given character cannot be used directly in a string

    • isParameter

      public static boolean isParameter(char character)
      Determines whether the given character is the character used to identify an input parameter, either a named parameter or position parameter.
      Parameters:
      character - The character to check if it's a parameter
      Returns:
      true if the given character is either : or ?; false otherwise

    • isQuote

      public static boolean isQuote(char character)
      Determines whether the given character is the single or double quote.
      Parameters:
      character - The character to check if it's a quote
      Returns:
      true if the given character is either ' or "; false otherwise

    • isWhiteSpace

      public static boolean isWhiteSpace(char character)
      Determines whether the given character is whitespace. Supports non-breaking space characters
      Parameters:
      character - The character to check if it's whitespace
      Returns:
      true if the given character is either whitespace or non-breaking space; false otherwise

    • quote

      public static String quote(String text)
      Returns the given string literal by wrapping it with single quotes. Any single quote within the string will be escaped with another single quote.
      Parameters:
      text - The original text to quote
      Returns:
      The quoted text

    • reposition

      public static void reposition(CharSequence query1, int[] positions, CharSequence query2)
      Adjusts the positions contained by the given array of either one or two elements, which is based on the given query1, by translating those positions to be at the equivalent position within query2.

      Important: The two JPQL queries should contain the same characters but the amount of whitespace can differ. One cannot have the escape characters and the other one has the Unicode characters.

      Parameters:
      query1 - The query where the positions are pointing
      positions - An array of either one or two elements positioned within query1
      query2 - The query for which the positions might need adjustment

    • repositionCursor

      public static int repositionCursor(CharSequence query1, int position1, CharSequence query2)
      Adjusts the position, which is based on the given query1, by translating it to be at the equivalent position within query2.

      Important: The two JPQL queries should contain the same characters but the amount of whitespace can differ. One cannot have the escape characters and the other one has the Unicode characters.

      Parameters:
      query1 - The query where the positions are pointing
      position1 - The position of a cursor within query1
      query2 - The query for which the position might need adjustment
      Returns:
      The adjusted position by moving it based on the difference between query1 and query2
      See Also:

    • repositionJava

      public static void repositionJava(CharSequence query, int[] positions)
      Re-adjusts the given positions, which is based on the non-escaped version of the given query, by making sure it is pointing at the same position within query, which contains references (escape characters).

      The escape characters are either \b, \t, \n, \f, \r, \", \' and \0 through \7.

      Important: The given query should contain the exact same amount of whitespace than the query used to calculate the given positions.

      Parameters:
      query - The query that may contain escape characters
      positions - The position within the non-escaped version of the given query, which is either a single element position or two positions that is used as a text range. After execution contains the adjusted positions by moving it based on the difference between the escape and non-escaped versions of the query

    • startWithIgnoreCase

      public static boolean startWithIgnoreCase(String string, String prefix)
      Determines whether the given string starts with the given prefix and ignores the case. If the prefix is null or an empty string, then true is always returned.
      Parameters:
      string - The string to check if its beginning matches the prefix
      prefix - The prefix used to test matching the beginning of the sequence of characters
      Returns:
      true if the given string begins with the given prefix and ignores the case; false otherwise

    • stringIsEmpty

      public static boolean stringIsEmpty(CharSequence text)
      Determines whether the specified string is null, empty, or contains only whitespace characters.
      Parameters:
      text - The sequence of character to test if it is null or only contains whitespace
      Returns:
      true if the given string is null or only contains whitespace; false otherwise

    • stringIsNotEmpty

      public static boolean stringIsNotEmpty(CharSequence text)
      Determines whether the specified string is NOT null, NOT empty, or contains at least one non-whitespace character.
      Parameters:
      text - The sequence of character to test if it is NOT null or does not only contain whitespace
      Returns:
      true if the given string is NOT null or has at least one non-whitespace character; false otherwise

    • stringsAreDifferentIgnoreCase

      public static boolean stringsAreDifferentIgnoreCase(CharSequence value1, CharSequence value2)
      Determines whether the two sequence of characters are different, with the appropriate null checks and the case is ignored.
      Parameters:
      value1 - The first value to check for equality and equivalency
      value2 - The second value to check for equality and equivalency
      Returns:
      true if both values are different; false otherwise

    • stringsAreEqualIgnoreCase

      public static boolean stringsAreEqualIgnoreCase(CharSequence value1, CharSequence value2)
      Determines whether the two sequence of characters are equal or equivalent, with the appropriate null checks and the case is ignored.
      Parameters:
      value1 - The first value to check for equality and equivalency
      value2 - The second value to check for equality and equivalency
      Returns:
      true if both values are null, equal or equivalent; false otherwise

    • unescape

      public static String unescape(CharSequence value, int[] position)
      Converts the string representation of the escape characters contained by the given CharSequence into the actual escape characters. For example, the string '\\b' is converted into the character value '\b'.
      Parameters:
      value - The sequence of characters to convert to an escaped version
      position - This is a one element array that needs to be adjusted when an escape character is converted
      Returns:
      The new sequence of characters that contains escape characters rather than their string representation

    • unquote

      public static String unquote(String text)
      Returns the string literal without the single or double quotes. Any two consecutive single quotes will be converted into a single quote.
      Parameters:
      text - The original text to unquote if it has ' at the beginning and the end
      Returns:
      The unquoted text

    • valuesAreDifferent

      public static boolean valuesAreDifferent(Object value1, Object value2)
      Determines whether the values are different, with the appropriate null checks.
      Parameters:
      value1 - The first value to check for equality and equivalency
      value2 - The second value to check for equality and equivalency
      Returns:
      true if both values are different; true if they are both null, equal or equivalent

    • valuesAreEqual

      public static boolean valuesAreEqual(Object value1, Object value2)
      Determines whether the values are equal or equivalent, with the appropriate null checks.
      Parameters:
      value1 - The first value to check for equality and equivalency
      value2 - The second value to check for equality and equivalency
      Returns:
      true if both values are null, equal or equivalent; false otherwise