/*
 * Copyright (c) 2001 Matthew Feldt. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided the copyright notice above is
 * retained.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND WITHOUT ANY EXPRESSED OR
 * IMPLIED WARRANTIES.
 */

/**
 * TestReader.java
 *
 * Java Examples In A Nutshell Copyright (c) 2000 David Flanagan
 * Exercise 3-8:
 * Write a simple cubclass of Reader named TestReader that returns the same
 * character (a character passed to the constructor) over and over. The stream
 * should never reach EOF. Write a trivial subclass of Writer named NullWriter
 * that simply discards any output sent to it. Streams like these are occasionally
 * useful for testing and other purposes. Write a test program that reads from the
 * TestReader and sends its output to a PrintWriter wrapped around a NullWriter.
 *
 * @author Matthew Feldt <developer@feldt.com>
 * @version 1.0, 02/12/2001 11:11
 */

package com.feldt.examples.io;
import java.io.*;
import com.feldt.examples.io.NullWriter;

public class TestReader extends Reader {
	private char ch;

	TestReader(char c) {
		ch = c;
	}

	/** read a single character, returns ch */
	public int read() {
		return (int)ch;
	}

	/** read characters in to an array, fill cbuf with ch */
	public int read(char[] cbuf) {
		for (int i = 0; i < cbuf.length; i++)
			cbuf[i] = ch;

		return cbuf.length;
	}

	/**
	 * read characters in to a portion of an array,
	 * fills cbuf from off to len with ch
	 */
	public int read(char[] cbuf, int off, int len) throws IOException {
		int bytes_read = 0;

		// protect the user from themself
		if ((off < 0) || (off > cbuf.length) || (len < 0) ||
			    ((off + len) > cbuf.length) || ((off + len) < 0)) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
			return 0;
        }

		for (int pos = off, i = 0; i < len; i++, pos++) {
			cbuf[pos] = ch;
			bytes_read++;
		}

		return bytes_read;
	}

	public void close() {}
	public void mark(int readAheadLimit) throws IOException {}
	public boolean markSupported() { return false; } // don't support marking
	public boolean ready() { return true; } // always ready
	public void reset() throws IOException {}
	public long skip(long n) throws IOException { return n; } // always true

	/** test class */
	static class Test {
        public static void main (String args[]) {
			Reader in;
		    PrintWriter out = new PrintWriter(new NullWriter());
	    	char[] buf = new char[8];

			try {
				in = new TestReader('a'); // test read()
			    System.out.println("in.read(): " + (char)in.read());

		        in.read(buf); // test read(char[])
				System.out.print("in.read(buf): ");
				System.out.println(buf);

				in = new TestReader('z'); // test read(char[], int, int)
				in.read(buf, 7, 1);
				System.out.print("in.read(buf, 7, 1): ");
				System.out.println(buf);

				in = new TestReader('m'); // second test read(char[], int, int)
				in.read(buf, 2, 3);
				System.out.print("in.read(buf, 2, 3): ");
				System.out.println(buf);

				try {
				    in.read(buf, 10, 5); // test bounds checking
				} catch(IndexOutOfBoundsException e) {
					System.out.println("Got IndexOutOfBoundsException as expected.");
				}
		    } catch(IOException e) {}
        }
	}
}