org.cassandraunit.dataset.cql.SimpleCQLLexer Maven / Gradle / Ivy
package org.cassandraunit.dataset.cql;
import java.util.ArrayList;
import java.util.List;
/**
* @author Steve Nicolai
*/
/* see the full CQL grammar at:
* https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/cql3/Cql.g
*
* This parser a series of lines, removes comments and breaks the lines into statements
* at semicolon boundaries.
*/
public class SimpleCQLLexer {
String text;
enum LexState {
DEFAULT,
INSINGLELINECOMMENT,
INMULTILINECOMMENT,
INQUOTESTRING,
INSQUOTESTRING,
}
LexState state;
int pos;
public SimpleCQLLexer(List lines) {
StringBuffer t = new StringBuffer();
for (String l : lines) {
t.append(l.trim());
t.append('\n');
}
text = t.toString();
pos = 0;
state = LexState.DEFAULT;
}
char getChar() {
if (pos < text.length())
return text.charAt(pos++);
else
return 0;
}
char peekAhead() {
if (pos < text.length())
return text.charAt(pos); // don't advance
else
return 0;
}
/* Skip the peekAhead character and not copy it to the output.
*/
void advance() {
pos++;
}
List getStatements() {
List statements = new ArrayList();
StringBuffer statementUnderConstruction = new StringBuffer();
char c;
while ((c = getChar()) != 0) {
switch (state) {
case DEFAULT:
if (c == '/' && peekAhead() == '/') {
state = LexState.INSINGLELINECOMMENT;
advance();
} else if (c == '-' && peekAhead() == '-') {
state = LexState.INSINGLELINECOMMENT;
advance();
} else if (c == '/' && peekAhead() == '*') {
state = LexState.INMULTILINECOMMENT;
advance();
} else if (c == '\n') {
statementUnderConstruction.append(' ');
} else {
statementUnderConstruction.append(c);
if (c == '\"') {
state = LexState.INQUOTESTRING;
} else if (c == '\'') {
state = LexState.INSQUOTESTRING;
} else if (c == ';') {
statements.add(statementUnderConstruction.toString().trim());
statementUnderConstruction.setLength(0);
}
}
break;
case INSINGLELINECOMMENT:
if (c == '\n') {
state = LexState.DEFAULT;
}
break;
case INMULTILINECOMMENT:
if (c == '*' && peekAhead() == '/') {
state = LexState.DEFAULT;
advance();
}
break;
case INQUOTESTRING:
statementUnderConstruction.append(c);
if (c == '"') {
if (peekAhead() == '"') {
statementUnderConstruction.append(getChar());
} else {
state = LexState.DEFAULT;
}
}
break;
case INSQUOTESTRING:
statementUnderConstruction.append(c);
if (c == '\'') {
if (peekAhead() == '\'') {
statementUnderConstruction.append(getChar());
} else {
state = LexState.DEFAULT;
}
}
break;
}
}
String tmp = statementUnderConstruction.toString().trim();
if (tmp.length() > 0) {
statements.add(tmp);
}
return statements;
}
}