FluentSource is a Fluent API for marshalling [Guava CharSource] (http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/io/CharSource.html) into object sources.

The following example demonstrates wrapping CharSource and trasnforming into an integer source, and filtering out the odd numbers to calculate the sum.

int sumOfEven = FluentSource.on(CharSource.wrap("1,2,3,4,5"), ",")
    .transform(new Function<String, Integer>() {
        @Override
        public Integer apply(String input) {
            return Integer.valueOf(input);
        }
    })
    .filter(new Predicate<Integer>() {
        @Override
        public boolean apply(Integer input) {
            return input % 2 == 0;
        }
    })
    .readAll(new SourceProcessor<Integer, Integer>() {
        private int sum;
    
        @Override
        public boolean process(Integer input) {
            this.sum += input;
            return true;
        }
    
        @Override
        public Integer getResult() {
            return sum;
        }
    }); //6

The following example demonstrates reading a csv CharSource and transforming into a Map source.

//marshall into source of a single Map ["a":"1", "b":"2", "c":"3"]
FluentSource.onCsv(CharSource.wrap("a,b,c\n1,2,3"))

More detailed examples available here

The character stream in CharSource is usually too low level for coding business logic - we usually marshall them into custom object stream for easier processing. Therefore the FluentSource is convenient here in providing higher order function for transforming the low-level CharSource into higher level "object" source.

Also FluentSource adheres to the same TellDontAsk principle as CharSource so that the try with resource of the underlying Reader(Closeable) would not have to be cluttered in client usage.

All useful APIs in FluentSource, requires JDK 1.6 or higher.