Adding enum for SortMode and use it in ScriptSortBuilder

core/src/main/java/org/elasticsearch/search/sort/SortMode.java

@@ -0,0 +1,91 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.search.sort;
+
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.Locale;
+import java.util.Objects;
+
+/**
+ * Elasticsearch supports sorting by array or multi-valued fields. The SortMode option controls what array value is picked
+ * for sorting the document it belongs to. The mode option can have the following values:
+ * <ul>
+ * <li>min - Pick the lowest value.</li>
+ * <li>max - Pick the highest value.</li>
+ * <li>sum - Use the sum of all values as sort value. Only applicable for number based array fields.</li>
+ * <li>avg - Use the average of all values as sort value. Only applicable for number based array fields.</li>
+ * <li>median - Use the median of all values as sort value. Only applicable for number based array fields.</li>
+ * </ul>
+ */
+public enum SortMode implements Writeable<SortMode> {
+    /** pick the lowest value **/
+    MIN,
+    /** pick the highest value **/
+    MAX,
+    /** Use the sum of all values as sort value. Only applicable for number based array fields. **/
+    SUM,
+    /** Use the average of all values as sort value. Only applicable for number based array fields. **/
+    AVG,
+    /** Use the median of all values as sort value. Only applicable for number based array fields. **/
+    MEDIAN;
+
+    static SortMode PROTOTYPE = MIN;
+
+    @Override
+    public void writeTo(final StreamOutput out) throws IOException {
+        out.writeVInt(ordinal());
+    }
+
+    @Override
+    public SortMode readFrom(final StreamInput in) throws IOException {
+        int ordinal = in.readVInt();
+        if (ordinal < 0 || ordinal >= values().length) {
+            throw new IOException("Unknown SortMode ordinal [" + ordinal + "]");
+        }
+        return values()[ordinal];
+    }
+
+    public static SortMode fromString(final String str) {
+        Objects.requireNonNull(str, "input string is null");
+        switch (str.toLowerCase(Locale.ROOT)) {
+            case ("min"):
+                return MIN;
+            case ("max"):
+                return MAX;
+            case ("sum"):
+                return SUM;
+            case ("avg"):
+                return AVG;
+            case ("median"):
+                return MEDIAN;
+            default:
+                throw new IllegalArgumentException("Unknown SortMode [" + str + "]");
+        }
+    }
+
+    @Override
+    public String toString() {
+        return name().toLowerCase(Locale.ROOT);
+    }
+}

core/src/test/java/org/elasticsearch/search/sort/SortModeTest.java

@@ -0,0 +1,55 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.search.sort;
+
+import org.elasticsearch.test.ESTestCase;
+import org.junit.Rule;
+import org.junit.rules.ExpectedException;
+
+public class SortModeTest extends ESTestCase {
+
+    @Rule
+    public ExpectedException exceptionRule = ExpectedException.none();
+
+    public void testSortMode() {
+        // we rely on these ordinals in serialization, so changing them breaks bwc.
+        assertEquals(0, SortMode.MIN.ordinal());
+        assertEquals(1, SortMode.MAX.ordinal());
+        assertEquals(2, SortMode.SUM.ordinal());
+        assertEquals(3, SortMode.AVG.ordinal());
+        assertEquals(4, SortMode.MEDIAN.ordinal());
+
+        assertEquals("min", SortMode.MIN.toString());
+        assertEquals("max", SortMode.MAX.toString());
+        assertEquals("sum", SortMode.SUM.toString());
+        assertEquals("avg", SortMode.AVG.toString());
+        assertEquals("median", SortMode.MEDIAN.toString());
+
+        for (SortMode mode : SortMode.values()) {
+            assertEquals(mode, SortMode.fromString(mode.toString()));
+            assertEquals(mode, SortMode.fromString(mode.toString().toUpperCase()));
+        }
+
+        exceptionRule.expect(IllegalArgumentException.class);
+        exceptionRule.expectMessage("Unknown SortMode [xyz]");
+        SortMode.fromString("xyz");
+    }
+
+}