Merge r 752495:752496 from trunk to branch-0.19. Fixes HADOOP-5307.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.19@752501 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -51,6 +51,9 @@ Release 0.19.2 - Unreleased
 
     HADOOP-5392. Fixes a problem to do with JT crashing during recovery when
     the job files are garbled. (Amar Kamat vi ddas)
+
+    HADOOP-5307. Fix null value handling in StringUtils#arrayToString() and 
+    #getStrings(). (enis)
  
     HADOOP-5421. Removes the test TestRecoveryManager.java from the 0.19 branch
     as it has compilation issues. (ddas) 

src/core/org/apache/hadoop/util/StringUtils.java

@@ -110,20 +110,24 @@ public class StringUtils {
     return percentFormat.format(rounded / scale);
   }
   
+  private static final String NULL_STR_VALUE = "__null__";
+  
   /**
    * Given an array of strings, return a comma-separated list of its elements.
    * @param strs Array of strings
    * @return Empty string if strs.length is 0, comma separated list of strings
    * otherwise
    */
-  
   public static String arrayToString(String[] strs) {
     if (strs.length == 0) { return ""; }
     StringBuffer sbuf = new StringBuffer();
-    sbuf.append(strs[0]);
-    for (int idx = 1; idx < strs.length; idx++) {
-      sbuf.append(",");
-      sbuf.append(strs[idx]);
+    for (int idx = 0; idx < strs.length; idx++) {
+      if(idx != 0)
+        sbuf.append(",");
+      if(strs[idx] == null)
+        sbuf.append(NULL_STR_VALUE);
+      else
+        sbuf.append(strs[idx]);
     }
     return sbuf.toString();
   }
@@ -305,7 +309,11 @@ public class StringUtils {
     StringTokenizer tokenizer = new StringTokenizer (str,",");
     values = new ArrayList<String>();
     while (tokenizer.hasMoreTokens()) {
-      values.add(tokenizer.nextToken());
+      String value = tokenizer.nextToken();
+      if(value.equals(NULL_STR_VALUE))
+        values.add(null);
+      else
+        values.add(value);
     }
     return values;
   }
@@ -542,6 +550,7 @@ public class StringUtils {
       );
 
     Runtime.getRuntime().addShutdownHook(new Thread() {
+      @Override
       public void run() {
         LOG.info(toStartupShutdownString("SHUTDOWN_MSG: ", new String[]{
           "Shutting down " + classname + " at " + hostname}));

src/test/org/apache/hadoop/util/TestStringUtils.java

@@ -118,4 +118,89 @@ public class TestStringUtils extends TestCase {
     assertEquals(-1259520L, StringUtils.TraditionalBinaryPrefix.string2long("-1230k"));
     assertEquals(956703965184L, StringUtils.TraditionalBinaryPrefix.string2long("891g"));
   }
+  
+  private <T> void assertEquals(T[] expected, T[] actual) {
+    assertEquals(expected.length, actual.length);
+    for (int i = 0; i < expected.length; i++) {
+      assertEquals(expected[i], actual[i]);
+    }
+  }
+  
+  //internal to StringUtils
+  private static final String NULL_STR_VALUE = "__null__";
+  
+  public void testArrayToString() {
+    
+    //normal test
+    String[] arr1 = new String[] {"1", "2", "3", "4", "5", "6" }; 
+    String expected1 = "1,2,3,4,5,6";
+    assertEquals(expected1, StringUtils.arrayToString(arr1));
+    
+    //test with whitespace
+    String[] arr2 = new String[] {"1 ", "2 ", "3 ", "4 ", "5 ", "6 " }; 
+    String expected2 = "1 ,2 ,3 ,4 ,5 ,6 ";
+    assertEquals(expected2, StringUtils.arrayToString(arr2));
+    
+    //test with empty array
+    String[] emptyArr = new String[0];
+    assertEquals("", StringUtils.arrayToString(emptyArr));
+    
+    //test with null
+    try {
+      StringUtils.arrayToString(null);
+      fail("Should have thrown NPE");
+    }catch(NullPointerException ex) {
+    }
+    
+    //test with one element 
+    assertEquals("1", StringUtils.arrayToString(new String[] {"1"}));
+    assertEquals("", StringUtils.arrayToString(new String[] {""}));
+    assertEquals(" ", StringUtils.arrayToString(new String[] {" "}));
+    
+    
+    assertEquals(" ,1", StringUtils.arrayToString(new String[] {" ", "1"}));
+    
+    //test with null values
+    assertEquals(NULL_STR_VALUE, StringUtils.arrayToString(new String[] {null}));
+    assertEquals(NULL_STR_VALUE+",1", StringUtils.arrayToString(new String[] {null,"1"}));
+    assertEquals("1," + NULL_STR_VALUE, StringUtils.arrayToString(new String[] {"1",null}));
+    
+  }
+  
+  public void testArrayToStringToArray() {
+    
+    //normal test
+    String[] arr1 = new String[] {"1", "2", "3", "4", "5", "6" };
+    assertEquals(arr1, StringUtils.getStrings(StringUtils.arrayToString(arr1)));
+    
+    //test with whitespace
+    String[] arr2 = new String[] {"1 ", "2 ", "3 ", "4 ", "5 ", "6 " }; 
+    assertEquals(arr2, StringUtils.getStrings(StringUtils.arrayToString(arr2)));
+    
+    //test with empty array
+    String[] emptyArr = new String[0];
+    //actually returns null for empty array
+    assertNull(StringUtils.getStrings(StringUtils.arrayToString(emptyArr)));
+    
+    //test with one element 
+    String[] one = new String[] {"1"};
+    String[] empty = new String[] {""};
+    String[] ws = new String[] {" "};
+    assertEquals(one, StringUtils.getStrings(StringUtils.arrayToString(one)));
+    assertNull(StringUtils.getStrings(StringUtils.arrayToString(empty)));
+    assertEquals(ws, StringUtils.getStrings(StringUtils.arrayToString(ws)));
+    
+    String[] wsone = new String[] {" ", "1"};
+    assertEquals(wsone, StringUtils.getStrings(StringUtils.arrayToString(wsone)));
+    
+    //test with null values
+    String[] nullArr = new String[] {null};
+    String[] nullArr2 =  new String[] {null, "1"};
+    String[] nullArr3 =  new String[] {null, "null", null};
+    String[] nullArr4 =  new String[] {null, null, null};
+    assertEquals(nullArr, StringUtils.getStrings(StringUtils.arrayToString(nullArr)));
+    assertEquals(nullArr2, StringUtils.getStrings(StringUtils.arrayToString(nullArr2)));
+    assertEquals(nullArr4, StringUtils.getStrings(StringUtils.arrayToString(nullArr4)));
+  }
+  
 }