Add KeyParserFactory that operates on an enum (#2007)

warehouse/query-core/src/main/java/datawave/query/data/parsers/KeyParserFactory.java

@@ -0,0 +1,35 @@
+package datawave.query.data.parsers;
+
+/**
+ * Utility to create a {@link KeyParser} from a {@link PARSER_TYPE}
+ */
+public class KeyParserFactory {
+
+    public enum PARSER_TYPE {
+        FIELD_INDEX, EVENT, TERM_FREQUENCY
+    }
+
+    private KeyParserFactory() {
+        // static utility
+    }
+
+    /**
+     * Create a KeyParser from the provided type
+     *
+     * @param type
+     *            the kind of key parser to create
+     * @return a key parser
+     */
+    public static KeyParser create(PARSER_TYPE type) {
+        switch (type) {
+            case FIELD_INDEX:
+                return new FieldIndexKey();
+            case EVENT:
+                return new EventKey();
+            case TERM_FREQUENCY:
+                return new TermFrequencyKey();
+            default:
+                return null;
+        }
+    }
+}

warehouse/query-core/src/test/java/datawave/query/data/parsers/KeyParserFactoryTest.java

@@ -0,0 +1,28 @@
+package datawave.query.data.parsers;
+
+import datawave.query.data.parsers.KeyParserFactory.PARSER_TYPE;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public class KeyParserFactoryTest {
+
+    @Test
+    public void testCreateFieldIndexKey() {
+        KeyParser parser = KeyParserFactory.create(PARSER_TYPE.FIELD_INDEX);
+        assertTrue(parser instanceof FieldIndexKey);
+    }
+
+    @Test
+    public void testCreateEventKey() {
+        KeyParser parser = KeyParserFactory.create(PARSER_TYPE.EVENT);
+        assertTrue(parser instanceof EventKey);
+    }
+
+    @Test
+    public void testCreateTermFrequencyKey() {
+        KeyParser parser = KeyParserFactory.create(PARSER_TYPE.TERM_FREQUENCY);
+        assertTrue(parser instanceof TermFrequencyKey);
+    }
+
+}