HADOOP-2366. Support trimmed strings in Configuration. Contributed by Michele Catasta

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@789973 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -468,6 +468,9 @@ Trunk (unreleased changes)
     than the max of the current length and the proposed length to improve
     performance reading large values. (thushara wijeratna via cdouglas)
 
+    HADOOP-2366. Support trimmed strings in Configuration.  (Michele Catasta
+    via szetszwo)
+
   OPTIMIZATIONS
 
     HADOOP-5595. NameNode does not need to run a replicator to choose a

src/java/org/apache/hadoop/conf/Configuration.java

@@ -31,6 +31,7 @@
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -740,6 +741,56 @@ public String[] getStrings(String name, String... defaultValue) {
     }
   }
   
+  /** 
+   * Get the comma delimited values of the <code>name</code> property as 
+   * a collection of <code>String</code>s, trimmed of the leading and trailing whitespace.  
+   * If no such property is specified then empty <code>Collection</code> is returned.
+   *
+   * @param name property name.
+   * @return property value as a collection of <code>String</code>s, or empty <code>Collection</code> 
+   */
+  public Collection<String> getTrimmedStringCollection(String name) {
+    String valueString = get(name);
+    if (null == valueString) {
+      Collection<String> empty = Collections.emptyList();
+      return empty;
+    }
+    return StringUtils.getTrimmedStringCollection(valueString);
+  }
+  
+  /** 
+   * Get the comma delimited values of the <code>name</code> property as 
+   * an array of <code>String</code>s, trimmed of the leading and trailing whitespace.
+   * If no such property is specified then an empty array is returned.
+   * 
+   * @param name property name.
+   * @return property value as an array of trimmed <code>String</code>s, 
+   *         or empty array. 
+   */
+  public String[] getTrimmedStrings(String name) {
+    String valueString = get(name);
+    return StringUtils.getTrimmedStrings(valueString);
+  }
+
+  /** 
+   * Get the comma delimited values of the <code>name</code> property as 
+   * an array of <code>String</code>s, trimmed of the leading and trailing whitespace.
+   * If no such property is specified then default value is returned.
+   * 
+   * @param name property name.
+   * @param defaultValue The default value
+   * @return property value as an array of trimmed <code>String</code>s, 
+   *         or default value. 
+   */
+  public String[] getTrimmedStrings(String name, String... defaultValue) {
+    String valueString = get(name);
+    if (null == valueString) {
+      return defaultValue;
+    } else {
+      return StringUtils.getTrimmedStrings(valueString);
+    }
+  }
+
   /** 
    * Set the array of string values for the <code>name</code> property as 
    * as comma delimited values.  

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

@@ -319,6 +319,29 @@ public static Collection<String> getStringCollection(String str){
     return values;
   }
 
+  /**
+   * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
+   * @param str a comma separated <String> with values
+   * @return a <code>Collection</code> of <code>String</code> values
+   */
+  public static Collection<String> getTrimmedStringCollection(String str){
+    return Arrays.asList(getTrimmedStrings(str));
+  }
+  
+  /**
+   * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
+   * @param str a comma separated <String> with values
+   * @return an array of <code>String</code> values
+   */
+  public static String[] getTrimmedStrings(String str){
+    if (null == str || "".equals(str.trim())) {
+      return emptyStringArray;
+    }
+
+    return str.trim().split("\\s*,\\s*");
+  }
+
+  final public static String[] emptyStringArray = {};
   final public static char COMMA = ',';
   final public static String COMMA_STR = ",";
   final public static char ESCAPE_CHAR = '\\';

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

@@ -22,6 +22,7 @@
 import java.util.List;
 
 import junit.framework.TestCase;
+import static org.junit.Assert.assertArrayEquals;
 
 public class TestStringUtils extends TestCase {
   final private static String NULL_STR = null;
@@ -132,4 +133,24 @@ public void testJoin() {
     assertEquals("a:b", StringUtils.join(":", s.subList(0, 2)));
     assertEquals("a:b:c", StringUtils.join(":", s.subList(0, 3)));
   }
+  
+  public void testGetTrimmedStrings() throws Exception {
+    String compactDirList = "/spindle1/hdfs,/spindle2/hdfs,/spindle3/hdfs";
+    String spacedDirList = "/spindle1/hdfs, /spindle2/hdfs, /spindle3/hdfs";
+    String pathologicalDirList1 = " /spindle1/hdfs  ,  /spindle2/hdfs ,/spindle3/hdfs ";
+    String pathologicalDirList2 = " /spindle1/hdfs  ,  /spindle2/hdfs ,/spindle3/hdfs , ";
+    String emptyList1 = "";
+    String emptyList2 = "   ";
+    
+    String[] expectedArray = {"/spindle1/hdfs", "/spindle2/hdfs", "/spindle3/hdfs"};
+    String[] emptyArray = {};
+    
+    assertArrayEquals(expectedArray, StringUtils.getTrimmedStrings(compactDirList));
+    assertArrayEquals(expectedArray, StringUtils.getTrimmedStrings(spacedDirList));
+    assertArrayEquals(expectedArray, StringUtils.getTrimmedStrings(pathologicalDirList1));
+    assertArrayEquals(expectedArray, StringUtils.getTrimmedStrings(pathologicalDirList2));
+    
+    assertArrayEquals(emptyArray, StringUtils.getTrimmedStrings(emptyList1));
+    assertArrayEquals(emptyArray, StringUtils.getTrimmedStrings(emptyList2));
+  } 
 }