Re: unnecessary code in Oracle example?

From:

markspace <markspace@nospam.nospam>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 09 Oct 2013 12:27:29 -0700

Message-ID:

<l34an4$ic1$1@dont-email.me>

On 10/9/2013 12:08 PM, Jim Janney wrote:

Thanks. But that looks like a good idiom to avoid. I prefer

    MyResource r1 = openResource();
    try {
       MyResource r2 = openResource2();
       try {
         // do something
       } finally {
         r2.close();
       }
    } finally {
      r1.close();
    }

Not as pretty syntactically, perhaps, but much clearer semantically.

I don't like either one. Why not take advantage of the fact that
resources are specified to be closed in the opposite order that they are
declared in a try-with-resources?

The following demonstrates this by closing the named streams in the
order C-B-A:

package quicktest;

import java.io.IOException;
import java.io.InputStream;

public class TryResourcesTest
{
    public static void main( String[] args ) throws Exception
    {
       try(
           MyTestStream a = new MyTestStream( "A" );
           MyTestStream b = new MyTestStream( "B" );
           MyTestStream c = new MyTestStream( "C" )
       ) {
          System.out.println( a.read()+b.read()+c.read() );
       }
    }
}

class MyTestStream extends InputStream {

    private final String name;

    public MyTestStream( String name ) {
       this.name = name;
    }

    @Override
    public int read() throws IOException {
       return 42;
    }

    @Override
    public void close() {
       System.out.println( getClass().getSimpleName()+
        ":"+name+" closed." );
    }
}