/**
* Return the next monitored token. Test the token following the monitored token. If following is
* another monitored token, save it for the next invocation of nextToken (like a single lookahead
* token) and return it then. If following is unmonitored, nondiscarded (hidden) channel token,
* add it to the monitored token.
*
* <p>Note: EOF must be a monitored Token.
*/
public Token nextToken() throws TokenStreamException {
// handle an initial condition; don't want to get lookahead
// token of this splitter until first call to nextToken
if (LA(1) == null) {
consumeFirst();
}
// we always consume hidden tokens after monitored, thus,
// upon entry LA(1) is a monitored token.
CommonHiddenStreamToken monitored = LA(1);
// point to hidden tokens found during last invocation
monitored.setHiddenBefore(lastHiddenToken);
lastHiddenToken = null;
// Look for hidden tokens, hook them into list emanating
// from the monitored tokens.
consume();
CommonHiddenStreamToken p = monitored;
// while hidden or discarded scarf tokens
while (hideMask.member(LA(1).getType()) || discardMask.member(LA(1).getType())) {
if (hideMask.member(LA(1).getType())) {
// attach the hidden token to the monitored in a chain
// link forwards
p.setHiddenAfter(LA(1));
// link backwards
if (p != monitored) { // hidden cannot point to monitored tokens
LA(1).setHiddenBefore(p);
}
p = lastHiddenToken = LA(1);
}
consume();
}
return monitored;
}
/**
* Make sure current lookahead symbol matches the given set Throw an exception upon mismatch,
* which is catch by either the error handler or by the syntactic predicate.
*/
public void match(BitSet b) throws MismatchedTokenException, TokenStreamException {
if (!b.member(LA(1)))
throw new MismatchedTokenException(tokenNames, LT(1), b, false, getFilename());
else
// mark token as consumed -- fetch next token deferred until LA/LT
consume();
}
private void consumeFirst() throws TokenStreamException {
consume(); // get first token of input stream
// Handle situation where hidden or discarded tokens
// appear first in input stream
CommonHiddenStreamToken p = null;
// while hidden or discarded scarf tokens
while (hideMask.member(LA(1).getType()) || discardMask.member(LA(1).getType())) {
if (hideMask.member(LA(1).getType())) {
if (p == null) {
p = LA(1);
} else {
p.setHiddenAfter(LA(1));
LA(1).setHiddenBefore(p); // double-link
p = LA(1);
}
lastHiddenToken = p;
if (firstHidden == null) {
firstHidden = p; // record hidden token if first
}
}
consume();
}
}
/** Returns a clean error message (no line number/column information) */
public String getMessage() {
StringBuffer sb = new StringBuffer();
switch (mismatchType) {
case CHAR:
sb.append("expecting ");
appendCharName(sb, expecting);
sb.append(", found ");
appendCharName(sb, foundChar);
break;
case NOT_CHAR:
sb.append("expecting anything but '");
appendCharName(sb, expecting);
sb.append("'; got it anyway");
break;
case RANGE:
case NOT_RANGE:
sb.append("expecting token ");
if (mismatchType == NOT_RANGE) sb.append("NOT ");
sb.append("in range: ");
appendCharName(sb, expecting);
sb.append("..");
appendCharName(sb, upper);
sb.append(", found ");
appendCharName(sb, foundChar);
break;
case SET:
case NOT_SET:
sb.append("expecting " + (mismatchType == NOT_SET ? "NOT " : "") + "one of (");
int[] elems = set.toArray();
for (int i = 0; i < elems.length; i++) {
appendCharName(sb, elems[i]);
}
sb.append("), found ");
appendCharName(sb, foundChar);
break;
default:
sb.append(super.getMessage());
break;
}
return sb.toString();
}
/** Consume tokens until one matches the given token set */
public void consumeUntil(BitSet set) throws TokenStreamException {
while (LA(1) != Token.EOF_TYPE && !set.member(LA(1))) {
consume();
}
}
public void hide(int m) {
hideMask.add(m);
}
