Java流阅读器一直阻塞到流结束

Question

Basically, I have written myself some InputStream (for further use as System.in), which accepts and consumes buffer loaded by Swing components.

NOTE: Print statements were inserted for debugging purposes.

The read() method:

@Override
public int read() {
    System.out.print("[READ] Querying buffer... ");
    while(this.buffer.isEmpty());
    int val = buffer.poll(); // Consumes the first element
    System.out.format("done - 0x%x\n",  val);
    return val;
}

Reading raw bytes from stream WORKS:

InputStream input = new TestStream();
int chunk = 0;
while(chunk != '\n') {
    chunk = input.read();
    System.out.format("Byte: 0x%x", chunk);
}
input.close();

Output:

[Read] Querying buffer... done - 0x4c
Byte: 0x4c
...
Byte: 0x a

The 0x a is the NL character (Yeah I am on Unix like system)

It outputs consumed characters as the stream is supplied additional data, and blocks while not.

But this does NOT work:

InputStream input = new TestStream();
Scanner scn = new Scanner(input);
System.out.println("Line: " + scn.nextLine());
scn.close();
input.close();

This approach simply consumes all the available data in the input stream, and blocks until the end of stream ( read() returning -1 ) has been reached. Either it seems to completely ignore the NL character in the stream, or the NL is inserted into the buffer wrong way (I highly doubt it is the latter)

What do you think is the cause if the issue?

Answer 1

k5_ has already pointed out the answer in his comment:

Scanner doesnt use read() method. It uses read(byte[]) , did you override that?

But didn't rewrite it as answer so I did. All credits to him.