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Article View: borland.public.jbuilder.java.language
Article #15073

Pb with Collections.binarySearch algorithm

#15073
From: Gemplus Software
Date: Thu, 15 Jul 1999 00:00
45 lines
1745 bytes
Hello Everybody,

Here is my code :

public class TestPerf {
  Vector     myV;

  public Vector getVector() {
    return myV;
  }

  public TestPerf() {
    myV = new Vector();
  }

  public static void main(String[] args) {
    TestPerf testPerf = new TestPerf();
    final int nNbIter = 30000;
    testPerf.invokedStandalone = true;

    for (int i = 0 ; i < nNbIter; i++) {
      String myStr = "toto" + String.valueOf(i);
      testPerf.getVector().addElement(myStr);
    }

   String mySearchStrMid = "toto14999";
   int nPos = 0;
   //Object[] mySA = testPerf.getVector().toArray();
   //Arrays.sort(mySA);
   //nPos = Arrays.binarySearch(mySA, mySearchStrMid);
   nPos = Arrays.binarySearch(testPerf.getVector().toArray(),
mySearchStrMid);
   if ( nPos >= 0 )
      System.out.println("Value Mid in Vector = " +
(String)testPerf.getVector().toArray()[nPos]);
    }
}

I am suprised because, in the JDK 1.2 docs, they say that you have to
sort before applying the binarySearch. So,what's the matter ? If  I do
the same within a LinkedList it fails (Exception generated) and works if

I do a sort before calling the binarySearch algorithm .

Any Idea ?
Technical Details
Message-ID: <378DF275.418B1171@gemplus.com>
Path: arc1-ca.pugleaf.net!unknown!not-for-mail

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From: Gemplus Software <gemplus.software@gemplus.com>
Subject: Pb with Collections.binarySearch algorithm
Date: 1999/07/15
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