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A Paradox Java Driver (using JDBC 4)
/*
* Scanner.java 03/14/2009 Copyright (C) 2009 Leonardo Alves da Costa This program is free software: you can
* redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in
* the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a
* copy of the GNU General Public License along with this program. If not, see tokens = new ArrayList<>();
/**
* Value buffer.
*/
private final StringBuilder value = new StringBuilder(299);
/**
* Creates a new instance.
*
* @param buffer the buffer to read of.
* @throws SQLException in case of parse errors.
*/
Scanner(final String buffer) throws SQLException {
if (buffer == null) {
throw new SQLException("NULL SQL Query.", SQLStates.INVALID_SQL.getValue());
}
this.buffer = CharBuffer.wrap(buffer.trim());
}
/**
* Checks for maximum number dots allowed.
*
* @param dotCount the dot count.
* @throws SQLException in case of invalid dot count.
*/
private static void checkDotCount(final int dotCount) throws SQLException {
if (dotCount > 1) {
throw new SQLException("Invalid numeric format", SQLStates.INVALID_SQL.getValue());
}
}
/**
* Creates a token by value.
*
* @param value to convert.
* @return a new {@link Token}.
*/
private static Token getToken(final String value) {
if (value.isEmpty()) {
return null;
}
final TokenType token = TokenType.get(value.toUpperCase(Locale.US));
if (token != null) {
return new Token(token, value);
}
return new Token(TokenType.IDENTIFIER, value);
}
/**
* Check if is a character or a string.
*
* @param c the char to verify.
* @return true if c is a char.
*/
private static boolean isCharacters(final char c) {
boolean characters = false;
if (c == '\'') {
// characters
characters = true;
}
return characters;
}
/**
* If the char is a separator.
*
* @param value the char to identify.
* @return true if the char is a separator.
*/
private static boolean isSeparator(final char value) {
for (final char c : Scanner.SEPARATORS) {
if (c == value) {
return true;
}
}
return false;
}
/**
* if the value is a special char.
*
* @param value the value to identify.
* @return true if the value is a special char.
*/
private static boolean isSpecial(final char value) {
for (final char c : Scanner.SPECIAL) {
if (c == value) {
return true;
}
}
return false;
}
/**
* Gets the next value in buffer.
*
* @return the next char.
*/
private char nextChar() {
return this.buffer.get();
}
/**
* Parses identifier tokens.
*
* @return if this token is an character token.
* @throws SQLException in case of parser errors.
*/
private boolean parseIdentifier() throws SQLException {
while (this.hasNext()) {
final char c = this.nextChar();
// Ignore separators.
if (!Scanner.isSeparator(c)) {
if (Scanner.isSpecial(c)) {
this.value.append(c);
return false;
} else if ((c == '"') || (c == '\'')) {
// identifiers with special chars
final boolean characters = Scanner.isCharacters(c);
this.parseString(c);
return characters;
} else {
this.parseNumber(c);
return false;
}
}
}
return false;
}
/**
* Parses a numeric char.
*
* @param start the char to start of.
* @throws SQLException in case of parse errors.
*/
private void parseNumber(final char start) throws SQLException {
char c = start;
boolean numeric = false;
int dotCount = 0;
while (!Scanner.isSeparator(c) && ((numeric && (c == '.')) || !Scanner.isSpecial(c))) {
this.value.append(c);
if (this.value.length() == 1) {
numeric = Character.isDigit(this.value.charAt(0));
} else if (c == '.') {
dotCount++;
// Only one dot per numeric value
Scanner.checkDotCount(dotCount);
}
if (this.hasNext()) {
c = this.nextChar();
} else {
break;
}
}
if (Scanner.isSeparator(c) || Scanner.isSpecial(c)) {
this.pushBack();
}
}
/**
* Parses a {@link String} value.
*
* @param type the string type (special char used).
*/
private void parseString(final char type) {
char c;
do {
if (this.hasNext()) {
c = this.nextChar();
} else {
return;
}
if (c == type) {
if (this.hasNext()) {
c = this.nextChar();
} else {
return;
}
if (c == type) {
this.value.append(c);
// prevent breaking
c = ' ';
} else {
this.pushBack();
return;
}
} else {
this.value.append(c);
}
} while (c != type);
}
/**
* Push back the read char.
*/
private void pushBack() {
position(buffer, this.buffer.position() - 1);
}
/**
* If buffer has tokens.
*
* @return true if the buffer still have tokens.
*/
boolean hasNext() {
return !this.tokens.isEmpty() || this.buffer.hasRemaining();
}
/**
* Gets the next {@link Token} in buffer.
*
* @return the next {@link Token}.
* @throws SQLException in case of parse errors.
*/
Token nextToken() throws SQLException {
final int size = this.tokens.size();
if (size > 0) {
final Token token = this.tokens.get(size - 1);
this.tokens.remove(size - 1);
return token;
}
if (!this.hasNext()) {
throw new SQLException("Unexpected end of SELECT statement.", SQLStates.INVALID_SQL.getValue());
}
this.value.delete(0, this.value.length());
final boolean characters = this.parseIdentifier();
if (characters) {
return new Token(TokenType.CHARACTER, this.value.toString());
} else if (Character.isDigit(this.value.charAt(0))) {
return new Token(TokenType.NUMERIC, this.value.toString());
}
return Scanner.getToken(this.value.toString());
}
/**
* Push back the given token in buffer.
*
* @param token the token to push back.
*/
void pushBack(final Token token) {
this.tokens.add(token);
}
}
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