SOLR-10666: Add rank transformation Stream Evaluator

solr/core/src/java/org/apache/solr/handler/StreamHandler.java

@@ -175,6 +175,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       .withFunctionName("normalize", NormalizeEvaluator.class)
       .withFunctionName("rev", ReverseEvaluator.class)
       .withFunctionName("length", LengthEvaluator.class)
+      .withFunctionName("rank", RankEvaluator.class)
 
       // metrics
          .withFunctionName("min", MinMetric.class)

solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/RankEvaluator.java

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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.apache.solr.client.solrj.io.stream;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.math3.stat.ranking.NaturalRanking;
+import org.apache.solr.client.solrj.io.Tuple;
+import org.apache.solr.client.solrj.io.eval.ComplexEvaluator;
+import org.apache.solr.client.solrj.io.eval.StreamEvaluator;
+import org.apache.solr.client.solrj.io.stream.expr.Explanation;
+import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType;
+import org.apache.solr.client.solrj.io.stream.expr.Expressible;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParameter;
+import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
+
+public class RankEvaluator extends ComplexEvaluator implements Expressible {
+
+  private static final long serialVersionUID = 1;
+
+  public RankEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
+    super(expression, factory);
+  }
+
+  public List<Number> evaluate(Tuple tuple) throws IOException {
+    StreamEvaluator colEval = subEvaluators.get(0);
+
+    List<Number> numbers = (List<Number>)colEval.evaluate(tuple);
+    double[] values = new double[numbers.size()];
+    for(int i=0; i<numbers.size(); i++) {
+      values[i] = numbers.get(i).doubleValue();
+    }
+
+    NaturalRanking rank = new NaturalRanking();
+    double[] ranked = rank.rank(values);
+    List<Number> rankedList = new ArrayList();
+    for(int i=0; i<numbers.size(); i++) {
+      rankedList.add(ranked[i]);
+    }
+
+    return rankedList;
+  }
+
+  @Override
+  public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException {
+    StreamExpression expression = new StreamExpression(factory.getFunctionName(getClass()));
+    return expression;
+  }
+
+  @Override
+  public Explanation toExplanation(StreamFactory factory) throws IOException {
+    return new Explanation(nodeId.toString())
+        .withExpressionType(ExpressionType.EVALUATOR)
+        .withFunctionName(factory.getFunctionName(getClass()))
+        .withImplementingClass(getClass().getName())
+        .withExpression(toExpression(factory).toString());
+  }
+}

solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java

@@ -5349,6 +5349,64 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     assertTrue(reverse.get(3).doubleValue() == 100D);
   }
 
+  @Test
+  public void testRankTransform() throws Exception {
+    UpdateRequest updateRequest = new UpdateRequest();
+
+    int i=0;
+    while(i<50) {
+      updateRequest.add(id, "id_"+(++i),"test_dt", getDateString("2016", "5", "1"), "price_f", "400.00");
+    }
+
+    while(i<100) {
+      updateRequest.add(id, "id_"+(++i),"test_dt", getDateString("2015", "5", "1"), "price_f", "300.0");
+    }
+
+    while(i<150) {
+      updateRequest.add(id, "id_"+(++i),"test_dt", getDateString("2014", "5", "1"), "price_f", "500.0");
+    }
+
+    while(i<250) {
+      updateRequest.add(id, "id_"+(++i),"test_dt", getDateString("2013", "5", "1"), "price_f", "100.00");
+    }
+
+    updateRequest.commit(cluster.getSolrClient(), COLLECTIONORALIAS);
+
+    String expr = "timeseries("+COLLECTIONORALIAS+", q=\"*:*\", start=\"2013-01-01T01:00:00.000Z\", " +
+        "end=\"2016-12-01T01:00:00.000Z\", " +
+        "gap=\"+1YEAR\", " +
+        "field=\"test_dt\", " +
+        "count(*), sum(price_f), max(price_f), min(price_f))";
+
+    String cexpr = "let(a="+expr+", c=col(a, max(price_f)), tuple(reverse=rev(c), ranked=rank(c)))";
+
+    ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", cexpr);
+    paramsLoc.set("qt", "/stream");
+
+    String url = cluster.getJettySolrRunners().get(0).getBaseUrl().toString()+"/"+COLLECTIONORALIAS;
+    TupleStream solrStream = new SolrStream(url, paramsLoc);
+
+    StreamContext context = new StreamContext();
+    solrStream.setStreamContext(context);
+    List<Tuple> tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    List<Number> reverse = (List<Number>)tuples.get(0).get("reverse");
+    assertTrue(reverse.size() == 4);
+    assertTrue(reverse.get(0).doubleValue() == 400D);
+    assertTrue(reverse.get(1).doubleValue() == 300D);
+    assertTrue(reverse.get(2).doubleValue() == 500D);
+    assertTrue(reverse.get(3).doubleValue() == 100D);
+
+    List<Number> ranked = (List<Number>)tuples.get(0).get("ranked");
+    assertTrue(ranked.size() == 4);
+    assertTrue(ranked.get(0).doubleValue() == 1D);
+    assertTrue(ranked.get(1).doubleValue() == 4D);
+    assertTrue(ranked.get(2).doubleValue() == 2D);
+    assertTrue(ranked.get(3).doubleValue() == 3D);
+  }
+
+
 
 
   @Test