Help with Readable Interface

[fatabass]

package myPackage;

import java.io.IOException;
import java.nio.CharBuffer;
import java.util.Scanner;

public class RandomWords implements Readable
{
	private static final char[] capitals = "JASON".toCharArray();
	
	private int count;
	
	public RandomWords(int count) 
	{
		this.count = count;
	}
	
	@Override
	public int read(CharBuffer cb) throws IOException 
	{
		count = count-1;

		cb.append(capitals[count]);
		
		if(count == 0)
			return -1;
		
		return 0;
	}
	
	public static void main(String[] args)
	{
		Scanner s = new Scanner(new RandomWords(5));
		
		while(s.hasNext())
			System.out.println(s.next());
	}
}

Output: Nojas

Hi everyone,

My question is:
Can someone please tell me when the read() method is called ?
Can you also help with the charbuffer cb ? When is it created ? I do not see anyone creating a charbuffer cb here but it is used ?

Thanks.

[DarrylBurke]

Read the source of Scanner.java and you'll be able to find it.

-- see what the constructor does with the Readable argument
-- see how it is used and when/where its read(...) method is called.
-- see where the CharBuffer comes from

db

[fatabass]

This is all I can find and it does not answer my questions:

A scanner can read text from any object which implements the Readable interface. If an invocation of the underlying readable's Readable.read(java.nio.CharBuffer) method throws an IOException then the scanner assumes that the end of the input has been reached. The most recent IOException thrown by the underlying readable can be retrieved via the ioException() method.

[DarrylBurke]

Read the source, not the API. You'll find the sources in src.zip in your JDK installation folder.

db

[fatabass]

In the jdk folder I only see a folder named api

[DarrylBurke]

You're looking in the wrong folder. The JDK installation folder has about 5 or 6 folders and 7 or 8 files, none of which is named "api"

Search your computer for "src.zip"

db

[fatabass]

I definetly do not have that file. :(

[Fubarable]

I didn't get the source for 1.7 either with my download, but I know that you can get the source for Java 1.6 here:

Java SE Downloads

Search for "Java SE 6 JDK Source Code" on this page.

[DarrylBurke]

Sorry about that, and thanks for the info.

Oracle claims the src.zip ships with JDK7
JDK File Structure

There's an alternative download here:
jdk7src – Alternative to JDK src.zip with all publicly available source files

db

[fatabass]

Ok I found the Scanner.java in src-jdk.zip and opened it with notepad but it is impossible to read this.

Am I trying to read something wrong ?

[DarrylBurke]

Notepad doesn't correctly render newlines without carriage returns (\n without \r). Use a decent text or code editor.

What IDE do you use?

db

[fatabass]

Eclipse

[DarrylBurke]

Try opening the source in Eclipse's code editor then.

I use NetBeans, which can open files, in read-only mode, directly from a zip archive without the need to extract the files first. Maybe Eclipse has something like that -- wait for Fubarable or one of the Eclipse users to happen by.

db

[fatabass]

Is this the Javadoc mentioned here?

This here:

Scanner (Java Platform SE 6)