"Hello, Amigo! Today we'll explore some super interesting stuff: how to replace System.in input stream."
System.in is a simple static InputStream variable, but you can't simply assign a new value to it. But you can use the System.setIn() method.
First, we need to create a buffer, and then put some values into it. Then we'll wrap it in a class that knows how to read data from the buffer using the InputStream protocol.
This is how it looks:
Code
public static void main(String[] args) throws IOException
{
//Put data into a string
StringBuilder sb = new StringBuilder();
sb.append("Lena").append('\n');
sb.append("Olya").append('\n');
sb.append("Anya").append('\n');
String data = sb.toString();
//Wrap the string in a ByteArrayInputStream
InputStream is = new ByteArrayInputStream(data.getBytes());
//Replace in
System.setIn(is);
//Call an ordinary method that doesn't know about our changes
readAndPrintLine();
}
public static void readAndPrintLine() throws IOException
{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(isr);
while (true)
{
String line = reader.readLine();
if (line == null) break;
System.out.println(line);
}
reader.close();
isr.close();
}
"Bilaabo! This is the most interesting example I've seen. I didn't know you could do that. Thanks."
"You're welcome, Amigo."
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