SOLR-10813: Add arraySort Stream Evaluator

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

@@ -195,6 +195,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       .withFunctionName("hist", HistogramEvaluator.class)
       .withFunctionName("anova", AnovaEvaluator.class)
       .withFunctionName("movingAvg", MovingAverageEvaluator.class)
+      .withFunctionName("arraySort", ArraySortEvaluator.class)
 
       // metrics
          .withFunctionName("min", MinMetric.class)

solr/solrj/src/java/org/apache/solr/client/solrj/io/eval/ArraySortEvaluator.java

@@ -0,0 +1,77 @@
+/*
+ * 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.eval;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import org.apache.solr.client.solrj.io.Tuple;
+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 ArraySortEvaluator extends ComplexEvaluator implements Expressible {
+
+  private static final long serialVersionUID = 1;
+
+  public ArraySortEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
+    super(expression, factory);
+  }
+
+  public List<Number> evaluate(Tuple tuple) throws IOException {
+
+    if(subEvaluators.size() != 1) {
+      throw new IOException("Array sort evaluator expects 1 parameters found: "+subEvaluators.size());
+    }
+
+    StreamEvaluator colEval1 = subEvaluators.get(0);
+
+    List<Number> numbers1 = (List<Number>)colEval1.evaluate(tuple);
+    List<Number> numbers2 = new ArrayList();
+    numbers2.addAll(numbers1);
+    Collections.sort(numbers2, new Comparator<Number>() {
+      @Override
+      public int compare(Number o1, Number o2) {
+        Double d1 = o1.doubleValue();
+        Double d2 = o2.doubleValue();
+        return d1.compareTo(d2);
+      }
+    });
+    return numbers2;
+  }
+
+  @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

@@ -5808,9 +5808,32 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     tuple = tuples.get(0);
     p = tuple.getDouble("return-value");
     assertEquals(p, 2.4, 0.001);
-
   }
 
+  @Test
+  public void testArraySort() throws Exception {
+    String cexpr = "arraySort(array(11.5, 12.3, 4, 3, 1, 0))";
+    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);
+    Tuple tuple = tuples.get(0);
+    List<Number> asort = (List<Number>)tuple.get("return-value");
+    assertEquals(asort.size(), 6);
+    assertEquals(asort.get(0).doubleValue(), 0, 0.0);
+    assertEquals(asort.get(1).doubleValue(), 1, 0.0);
+    assertEquals(asort.get(2).doubleValue(), 3, 0.0);
+    assertEquals(asort.get(3).doubleValue(), 4, 0.0);
+    assertEquals(asort.get(4).doubleValue(), 11.5, 0.0);
+    assertEquals(asort.get(5).doubleValue(), 12.3, 0.0);
+  }
 
   @Test
   public void testCumulativeProbability() throws Exception {