/guava/guava/src/com/google/common/io/CharSource.java
if ( !lengthIfKnown.isPresent ( ) ) { return Optional.absent ( ) ; }
} @Override public Optional<Long> lengthIfKnown() { long result = 0L; for (CharSource source : sources) { Optional<Long> lengthIfKnown = source.lengthIfKnown(); <extra_id_0> result += lengthIfKnown.get(); } return Optional.of(result); } @Override public long length() throws IOException {