org.eclipse.persistence.jpa.jpql
Class WordParser

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

public final class WordParser
extends java.lang.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 parser.Expression 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:

2.4.2

Author:

Pascal Filion

Since:

2.3

Nested Class Summary

static class

WordParser.WordType This enumeration determines the type of word that was scanned.

Constructor Summary

WordParser(java.lang.CharSequence text)
Creates a new WordParser.

Method Summary

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, java.lang.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, java.lang.String suffix) Determines whether the query ends with the given suffix and the end position is the end of the range for testing.
java.lang.String	entireWord() Retrieves a word starting at the current position.
java.lang.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(java.lang.CharSequence word) Moves the position of the cursor by the length of the given word.
void	moveBackward(int position) Moves backward the position of the cursor by the given amount.
java.lang.String	moveForward(java.lang.CharSequence word) Moves the position of the cursor by the length of the given word.
java.lang.String	moveForward(int position) Moves forward the position of the cursor by the given amount.
java.lang.String	numericLiteral() Retrieves the numeric literal that should be the current word to parse.
java.lang.String	partialWord() Retrieves a word before the current position of the cursor, which determines when the parsing stop.
java.lang.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(java.lang.CharSequence prefix) Tests whether the query starts with the specified prefix from the current position.
boolean	startsWith(java.lang.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: { '+', '-', '*', '/' },
java.lang.Boolean	startsWithDigit() Determines if the text starts with a digit (true), an arithmetic term (false) or anything else (null).
boolean	startsWithIdentifier(java.lang.CharSequence identifier) Determines whether the text at the current position start with the following identifier.
boolean	startsWithIdentifier(java.lang.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(java.lang.CharSequence prefix) Tests if the string starts with the specified prefix.
boolean	startsWithIgnoreCase(java.lang.CharSequence prefix, int offset) Tests if the string starts with the specified prefix.
java.lang.String	substring() Returns a substring that is within the current position of the cursor and the end of the text.
java.lang.String	substring(int startIndex) Returns a substring that is within the given position and the end of the text.
java.lang.String	substring(int startIndex, int endIndex) Returns a substring that is within the given positions.
java.lang.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.
java.lang.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 Detail

WordParser

public WordParser(java.lang.CharSequence text)

Creates a new WordParser.

Parameters:

text - The string representation of the JPQL query

Method Detail

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,
                        java.lang.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,
                                  java.lang.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

Since:

2.5

entireWord

public java.lang.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 java.lang.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()

Since:

2.4

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:

Character.isWhitespace(char), isArithmeticSymbol(char), #isDelimitor(char)

length

public int length()

Returns the length of the string value.

Returns:

The total count of characters

moveBackward

public void moveBackward(java.lang.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 java.lang.String moveForward(java.lang.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 java.lang.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

numericLiteral

public java.lang.String numericLiteral()

Retrieves the numeric literal that should be the current word to parse.

Returns:

The numeric literal value

partialWord

public java.lang.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 java.lang.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(java.lang.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(java.lang.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 java.lang.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(java.lang.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(java.lang.CharSequence identifier,
                                    int position)

Determines whether the text at the current position start with the following identifier.

Parameters:

position - The position to start matching the characters

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

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(java.lang.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(java.lang.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 java.lang.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 java.lang.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 java.lang.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 java.lang.String toString()

Overrides:

toString in class java.lang.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 java.lang.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:

WordParser.word(), WordParser.WordType

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:

WordParser.word(), WordParser.WordType