fix issue where StringColumn asSet returns the underlying set from th…

…e DictionaryMap (jtablesaw#862)
Kerwinooooo · Jan 20, 2021 · 8bd0548 · 8bd0548
1 parent a470556
commit 8bd0548
Show file tree

Hide file tree

Showing 4 changed files with 21 additions and 4 deletions.
diff --git a/core/src/main/java/tech/tablesaw/columns/strings/ByteDictionaryMap.java b/core/src/main/java/tech/tablesaw/columns/strings/ByteDictionaryMap.java
@@ -17,6 +17,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -177,7 +178,7 @@ public int countOccurrences(String value) {
   }
 
   public Set<String> asSet() {
-    return categories();
+    return new HashSet<>(categories());
   }
 
   public int firstIndexOf(String value) {

diff --git a/core/src/main/java/tech/tablesaw/columns/strings/IntDictionaryMap.java b/core/src/main/java/tech/tablesaw/columns/strings/IntDictionaryMap.java
@@ -17,6 +17,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -176,7 +177,7 @@ public int countOccurrences(String value) {
   }
 
   public Set<String> asSet() {
-    return categories();
+    return new HashSet<>(categories());
   }
 
   public int firstIndexOf(String value) {

diff --git a/core/src/main/java/tech/tablesaw/columns/strings/ShortDictionaryMap.java b/core/src/main/java/tech/tablesaw/columns/strings/ShortDictionaryMap.java
@@ -17,6 +17,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -186,7 +187,7 @@ public int countOccurrences(String value) {
   }
 
   public Set<String> asSet() {
-    return categories();
+    return new HashSet<>(categories());
   }
 
   public int firstIndexOf(String value) {

diff --git a/core/src/test/java/tech/tablesaw/api/StringColumnTest.java b/core/src/test/java/tech/tablesaw/api/StringColumnTest.java
@@ -14,11 +14,16 @@
 
 package tech.tablesaw.api;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static tech.tablesaw.columns.strings.StringPredicates.isEqualToIgnoringCase;
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Set;
 import java.util.function.Function;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -69,6 +74,15 @@ void testForNulls() {
     assertEquals("", table2.stringColumn("id").get(3));
   }
 
+  /** Test that asSet returns a different set each time. */
+  @Test
+  void asSet() {
+    Set<String> set1 = column.asSet();
+    Set<String> set2 = column.asSet();
+    set1.remove("Value 2");
+    assertNotEquals(set1.size(), set2.size());
+  }
+
   @Test
   void testAppendObj() {
     StringColumn column = StringColumn.create("testing");