org.eclipse.persistence.jpa.jpql
Class ExpressionTools

java.lang.Object
  org.eclipse.persistence.jpa.jpql.ExpressionTools

public final class ExpressionTools
extends java.lang.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:

2.4.2

Author:

Pascal Filion

Since:

2.3

Field Summary

static java.lang.Object[]	EMPTY_ARRAY The constant of an empty array.
static java.lang.String	EMPTY_STRING The constant for an empty string.
static java.lang.String[]	EMPTY_STRING_ARRAY The constant of an empty String array.

Method Summary

static java.lang.String	escape(java.lang.CharSequence value, int[] position) Converts the escape characters contained in the given CharSequence to their literal representation.
static boolean	isFunctionExpression(WordParser wordParser, java.lang.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 java.lang.String	quote(java.lang.String text) Returns the given string literal by wrapping it with single quotes.
static void	reposition(java.lang.CharSequence query1, int[] positions, java.lang.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(java.lang.CharSequence query1, int position1, java.lang.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(java.lang.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(java.lang.String string, java.lang.String prefix) Determines whether the given string starts with the given prefix and ignores the case.
static boolean	stringIsEmpty(java.lang.CharSequence text) Determines whether the specified string is null, empty, or contains only whitespace characters.
static boolean	stringIsNotEmpty(java.lang.CharSequence text) Determines whether the specified string is NOT null, NOT empty, or contains at least one non-whitespace character.
static boolean	stringsAreDifferentIgnoreCase(java.lang.CharSequence value1, java.lang.CharSequence value2) Determines whether the two sequence of characters are different, with the appropriate null checks and the case is ignored.
static boolean	stringsAreEqualIgnoreCase(java.lang.CharSequence value1, java.lang.CharSequence value2) Determines whether the two sequence of characters are equal or equivalent, with the appropriate null checks and the case is ignored.
static java.lang.String	unescape(java.lang.CharSequence value, int[] position) Converts the string representation of the escape characters contained by the given CharSequence into the actual escape characters.
static java.lang.String	unquote(java.lang.String text) Returns the string literal without the single or double quotes.
static boolean	valuesAreDifferent(java.lang.Object value1, java.lang.Object value2) Determines whether the values are different, with the appropriate null checks.
static boolean	valuesAreEqual(java.lang.Object value1, java.lang.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 Detail

EMPTY_ARRAY

public static final java.lang.Object[] EMPTY_ARRAY

The constant of an empty array.

EMPTY_STRING

public static final java.lang.String EMPTY_STRING

The constant for an empty string.

See Also:

Constant Field Values

EMPTY_STRING_ARRAY

public static final java.lang.String[] EMPTY_STRING_ARRAY

The constant of an empty String array.

Method Detail

escape

public static java.lang.String escape(java.lang.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,
                                           java.lang.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

Since:

2.5

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

quote

public static java.lang.String quote(java.lang.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

Since:

2.4

reposition

public static void reposition(java.lang.CharSequence query1,
                              int[] positions,
                              java.lang.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

Since:

2.5

repositionCursor

public static int repositionCursor(java.lang.CharSequence query1,
                                   int position1,
                                   java.lang.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

position - 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:

reposition(CharSequence, int[], CharSequence)

repositionJava

public static void repositionJava(java.lang.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

Since:

2.5

startWithIgnoreCase

public static boolean startWithIgnoreCase(java.lang.String string,
                                          java.lang.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

Since:

2.5

stringIsEmpty

public static boolean stringIsEmpty(java.lang.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(java.lang.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(java.lang.CharSequence value1,
                                                    java.lang.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(java.lang.CharSequence value1,
                                                java.lang.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 java.lang.String unescape(java.lang.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 java.lang.String unquote(java.lang.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(java.lang.Object value1,
                                         java.lang.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(java.lang.Object value1,
                                     java.lang.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