static synchronized String sourceLine(Location location, int lineNumber) throws IOException {
if (lineNumber == -1) {
throw new IllegalArgumentException();
}
try {
String fileName = location.sourceName();
Iterator<SourceCode> iter = sourceCache.iterator();
SourceCode code = null;
while (iter.hasNext()) {
SourceCode candidate = iter.next();
if (candidate.fileName().equals(fileName)) {
code = candidate;
iter.remove();
break;
}
}
if (code == null) {
BufferedReader reader = sourceReader(location);
if (reader == null) {
throw new FileNotFoundException(fileName);
}
code = new SourceCode(fileName, reader);
if (sourceCache.size() == SOURCE_CACHE_SIZE) {
sourceCache.remove(sourceCache.size() - 1);
}
}
sourceCache.add(0, code);
return code.sourceLine(lineNumber);
} catch (AbsentInformationException e) {
throw new IllegalArgumentException();
}
}
