Databases
StackOverflow2013
Postsdbo
POJava - A Reader class able to interleave lines from multiple Readers
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POJava - A Reader class able to interleave lines from multiple Readers
    primarykey
    data
    text
    <p>What I would like is to end up with something like:</p> <pre><code>public class InterleavedBufferedReader extends BufferedReader { ... } </code></pre> <p>And use it as:</p> <pre><code>Reader[3] readers = ...; // three readers InterleavedBufferedReader ibr = new InterleavedBufferedReader(readers); ibr.readLine(); // this returns the first line of Reader 1 ibr.readLine(); // this returns the first line of Reader 2 ibr.readLine(); // this returns the first line of Reader 3 ibr.readLine(); // this returns the second line of Reader 1 ibr.readLine(); // this returns the second line of Reader 2 ibr.readLine(); // hey, Reader 3 had no more lines, return the third line of Reader 1 </code></pre> <p>What I tried (no good, I know, that's why I'm here):</p> <pre><code>public class InterleavedBufferedReader extends BufferedReader { static private int current = 0; private BufferedReader[] buffers; public InterleavedBufferedReader(BufferedReader[] in) { super(new StringReader("dummy")); buffers = in; } public InterleavedBufferedReader(Reader[] in) { super(new StringReader("dummy")); buffers = new BufferedReader[in.length]; for (int i=0 ; i &lt; in.length ; i++) buffers[i] = new BufferedReader(in[i]); } @Override public String readLine() throws IOException { int start = current; String line = null; while ((line = buffers[current].readLine()) == null) { current = (current+1) % buffers.length; if (current == start) return null; } current = (current+1) % buffers.length; return line; } @Override public void close() throws IOException { for (int i=0; i &lt; buffers.length; i++) buffers[i].close(); } } </code></pre> <p>Comments:</p> <ul> <li>The interleaved <code>readLine()</code> actually works!</li> <li>Perhaps I shouldn't be extending <code>BufferedReader</code>. I'm forced to give it a dummy Reader to manage, or it won't even compile. Meanwhile, I override the <code>readLine()</code> method to call it on the children readers. But the implementation is at least incomplete, because other methods, as <code>read()</code>, will actually refer to my dummy reader. </li> </ul> <p>I can I do this in a cleaner way?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. UScornuz
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POJava - A Reader class able to interleave lines from multiple Readers
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POJava - A Reader class able to interleave lines from multiple Readers
      1. USE_net4
      1. VTFavorite
    3. VO
      singulars
      1. POJava - A Reader class able to interleave lines from multiple Readers
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload