How to Set an Output Stream Java

Question

I mean if I've to create a method some kind of a: void setOutputStream(PrintStream stream). So the stream variable is an output stream where I'll write my data(which will preferably be a String variable). The question is, how it will dynamically determine the output stream and correctly write my data there, i.e. for System.out it'll print data on the screen, for file stream it'll write my data to the file.

Solution 1

I think you're looking for java.lang.System#setOut(PrintStream stream) method. Which essentially lets you reassign the standard output stream programmatically.

Solution 2

What you want to do is called Decorator pattern. You might want to review this answer (and the thread).

Look at the following class hierarchy (java.io.*Stream)

java.lang.Object 
    java.io.Console (implements java.io.Flushable) 
    java.io.File (implements java.lang.Comparable<T>, java.io.Serializable) 
    java.io.FileDescriptor 
    java.io.InputStream (implements java.io.Closeable) 
            java.io.ByteArrayInputStream 
            java.io.FileInputStream 
            java.io.FilterInputStream 
                    java.io.BufferedInputStream 
                    java.io.DataInputStream (implements java.io.DataInput) 

Good Luck!

Comments

[Helgus]

and if i want my function to print it on the screen? how to do it "dynamically"?

[Helgus]

it describes only File io, but i need another way of implementation

[Florent Guillaume]

I don't understand the "dynamically" part. If you want to print to the screen, then use System.out, it's a PrintStream object.

[aviad]

The idea is the same for all java.io.*streams the entire hierarchy implements the Decorator pattern and this is what you need to do.