CallChain

CallChain is a class that allow to construct linked chain of methods. Also there is some operators to manage data.

Example

/* Receiver. End point for our chain */

CallChain.Receiver receiver = new CallChain.Receiver<String>() {
    @Override
    public void onReceive(String data) {
        System.out.println("#receive: "+data);
    }

    @Override
    public void onError(Throwable err) {
        System.out.println("#error: "+err.getMessage());
    }

    @Override
    public void onComplete() {
        System.out.println("#complete");
    }
};


/* Start our chained process */

CallChain chain = new CallChain();
chain
        // producing sequence of Integers
        .just( getNumberArray(-2,10) )

        // convert array to single items
        .<Integer>flatMap()

        // calc sum of integers. return (value+value)
        .map(new CallChain.ICaller<Integer,Integer>() {
            @Override
            public Integer call(Integer data) {
                return data+data;
            }
        })

        // filter negative values
        .filter(new CallChain.ICaller<Integer,Boolean>() {
            @Override
            public Boolean call(Integer data) {
                return data >= 0;
            }
        })

        // append prefix "item " to a number, so that convert value to string
        .map(new CallChain.ICaller<Integer,String>() {
            @Override
            public String call(Integer data) {
                return "item "+data;
            }
        })

        // let's process data before uppercasing
        .catchData(new CallChain.ICallerIn<String>() {
            @Override
            public void call(String data) {
                //socket.send(data);
                System.out.println("send to socket: "+data);
            }
        })

        // uppercase incoming string
        .map(new CallChain.ICaller<String,String>() {
            @Override
            public String call(String data) {
                return data.toUpperCase();
            }
        })

        // try to replace "100" with "777"
        .map(new CallChain.ICaller<String,String>() {
            @Override
            public String call(String data) {
                return data.replace("100", "777");
            }
        })

        // take only first 5 items
        .take(5)

        // catch onComplete() event
        .catchComplete(new CallChain.ICallerVoid() {
            @Override
            public void call() {
                System.out.println("we are done!");
            }
        })

        // do something with result. (print to system.out here)
        .add(receiver);

chain.run();

//
private static Integer[] getNumberArray(int start, int count){

    Integer[] arr = new Integer[count];
    int sum = 0, index = 0;
    for (int k = start; k < start+count; ++k){
        sum += k;
        arr[index++] = sum;
    }
    return arr;
}

Output

send to socket: item 0
#receive: ITEM 0
send to socket: item 6
#receive: ITEM 6
send to socket: item 14
#receive: ITEM 14
send to socket: item 24
#receive: ITEM 24
send to socket: item 36
#receive: ITEM 36
#complete