throw EOFException when using empty files with ValueServer in replay and digest modes

JIRA: MATH-185

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@617850 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/math/random/EmpiricalDistributionImpl.java

@@ -17,6 +17,7 @@
 
 package org.apache.commons.math.random;
 
+import java.io.EOFException;
 import java.io.Serializable;
 import java.io.BufferedReader;
 import java.io.FileReader;
@@ -131,6 +132,9 @@ public class EmpiricalDistributionImpl implements Serializable, EmpiricalDistrib
             } catch (Exception e) {
                 throw new IOException(e.getMessage());
             }
+            if (sampleStats.getN() == 0) {
+                throw new EOFException("URL " + url + " contains no data");
+            }
             in = new BufferedReader(new InputStreamReader(url.openStream()));
             fillBinStats(in);
             loaded = true;

src/java/org/apache/commons/math/random/ValueServer.java

@@ -17,6 +17,7 @@
 
 package org.apache.commons.math.random;
 import java.io.BufferedReader;
+import java.io.EOFException;
 import java.io.InputStreamReader;
 import java.io.IOException;
 import java.net.URL;
@@ -308,7 +309,9 @@ public class ValueServer {
      * replay file open.</p>
      * <p>
      * The <code>valuesFileURL</code> will be closed and reopened to wrap around
-     * from EOF to BOF if EOF is encountered.</p>
+     * from EOF to BOF if EOF is encountered. EOFException (which is a kind of
+     * IOException) may still be thrown if the <code>valuesFileURL</code> is
+     * empty.</p>
      *
      * @return next value from the replay file
      * @throws IOException if there is a problem reading from the file
@@ -321,9 +324,12 @@ public class ValueServer {
             resetReplayFile();
         }
         if ((str = filePointer.readLine()) == null) {
+            // we have probably reached end of file, wrap around from EOF to BOF
             closeReplayFile();
             resetReplayFile();
-            str = filePointer.readLine();
+            if ((str = filePointer.readLine()) == null) {
+                throw new EOFException("URL " + valuesFileURL + " contains no data");
+            }
         }
         return Double.valueOf(str).doubleValue();
     }

src/test/org/apache/commons/math/random/ValueServerTest.java

@@ -18,6 +18,8 @@ package org.apache.commons.math.random;
 
 import junit.framework.Test;
 import junit.framework.TestSuite;
+
+import java.io.EOFException;
 import java.net.URL;
 
 import org.apache.commons.math.RetryTestCase;
@@ -98,7 +100,35 @@ public final class ValueServerTest extends RetryTestCase {
             fail("Expecting IllegalStateException");
         } catch (IllegalStateException ex) {;}
     }
-    
+
+    public void testEmptyReplayFile() {
+        try {
+            URL url = getClass().getResource("emptyFile.txt");
+            vs.setMode(ValueServer.REPLAY_MODE);
+            vs.setValuesFileURL(url);
+            vs.getNext();
+            fail("an exception should have been thrown");
+        } catch (EOFException eof) {
+            // expected behavior
+        } catch (Exception e) {
+            fail("wrong exception caught");
+        }
+    }
+
+    public void testEmptyDigestFile() {
+        try {
+            URL url = getClass().getResource("emptyFile.txt");
+            vs.setMode(ValueServer.DIGEST_MODE);
+            vs.setValuesFileURL(url);
+            vs.computeDistribution();
+            fail("an exception should have been thrown");
+        } catch (EOFException eof) {
+            // expected behavior
+        } catch (Exception e) {
+            fail("wrong exception caught");
+        }
+    }
+
     /**
      * Test ValueServer REPLAY_MODE using values in testData file.<br> 
      * Check that the values 1,2,1001,1002 match data file values 1 and 2.

xdocs/changes.xml

@@ -139,6 +139,10 @@ Commons Math Release Notes</title>
       <action dev="luc" type="fix" issue="MATH-182">
         Add integer overflow checks in Fraction constructor using double parameter.
       </action>     
+      <action dev="luc" type="fix" issue="MATH-185">
+        Throw EOFException when using empty files with ValueServer in replay and
+        digest modes.
+      </action>     
     </release>
     <release version="1.1" date="2005-12-17"  
  description="This is a maintenance release containing bug fixes and enhancements.