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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.

Since:

2.3

Version:

2.3

Author:

Pascal Filion

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.

Constructor Summary

private

ExpressionTools() ExpressionTools cannot be instantiated.

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	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	parseLiteral(WordParser wordParser) Retrieves the first word from the given text starting at the specified position.
static int	repositionCursor(java.lang.CharSequence query1, int position1, java.lang.CharSequence query2) Re-adjusts the given position, which is based on query1, by making sure it is pointing at the same position within query2.
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 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.

Constructor Detail

ExpressionTools

private ExpressionTools()

ExpressionTools cannot be instantiated.

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

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

parseLiteral

public static java.lang.String parseLiteral(WordParser wordParser)

Retrieves the first word from the given text starting at the specified position.

Parameters:

text - The text from which the first word will be retrieved

position - The position of the cursor where to start retrieving the word

Returns:

The first word contained in the text, if none could be found, then an empty string is returned

repositionCursor

public static int repositionCursor(java.lang.CharSequence query1,
                                   int position1,
                                   java.lang.CharSequence query2)

Re-adjusts the given position, which is based on query1, by making sure it is pointing at the same position within query2. Usually the position is moved because the two queries don't have the same amount of whitespace.

Parameters:

query1 - The query associated to the position

position1 - The position 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

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

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

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