SOLR-10504: Add echo Streaming Expression

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

@@ -159,6 +159,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       .withFunctionName("cartesianProduct", CartesianProductStream.class)
          .withFunctionName("shuffle", ShuffleStream.class)
          .withFunctionName("eval", CalculatorStream.class)
+      .withFunctionName("echo", EchoStream.class)
 
              // metrics
          .withFunctionName("min", MinMetric.class)

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

@@ -0,0 +1,119 @@
+/*
+ * 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.HashMap;
+import java.util.List;
+
+import org.apache.solr.client.solrj.io.Tuple;
+import org.apache.solr.client.solrj.io.comp.StreamComparator;
+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.StreamExplanation;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
+import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
+
+public class EchoStream extends TupleStream implements Expressible {
+
+  private static final long serialVersionUID = 1;
+  private boolean finished;
+  private String echo;
+
+  public EchoStream(String echo) throws IOException {
+    this.echo = stripQuotes(echo);
+  }
+
+  public EchoStream(StreamExpression expression, StreamFactory factory) throws IOException {
+    this.echo = stripQuotes(factory.getValueOperand(expression, 0));
+    this.echo = echo.replace("\\\"", "\"");
+  }
+
+  private String stripQuotes(String s){
+    if(s.startsWith("\"")) {
+      return s.substring(1, s.length()-1);
+    } else {
+      return s;
+    }
+  }
+
+  @Override
+  public StreamExpression toExpression(StreamFactory factory) throws IOException{
+    return toExpression(factory, true);
+  }
+
+  private StreamExpression toExpression(StreamFactory factory, boolean includeStreams) throws IOException {
+    // function name
+    StreamExpression expression = new StreamExpression(factory.getFunctionName(this.getClass()));
+    expression.addParameter("\""+echo.replace("\"", "\\\"")+"\"");
+    return expression;
+  }
+
+  @Override
+  public Explanation toExplanation(StreamFactory factory) throws IOException {
+
+    return new StreamExplanation(getStreamNodeId().toString())
+        .withFunctionName(factory.getFunctionName(this.getClass()))
+        .withImplementingClass(this.getClass().getName())
+        .withExpressionType(ExpressionType.STREAM_DECORATOR)
+        .withExpression(toExpression(factory, false).toString());
+  }
+
+  public void setStreamContext(StreamContext context) {
+  }
+
+  public List<TupleStream> children() {
+    List<TupleStream> l =  new ArrayList<TupleStream>();
+    return l;
+  }
+
+  public void open() throws IOException {
+
+  }
+
+  public void close() throws IOException {
+  }
+
+  public Tuple read() throws IOException {
+
+    if(finished) {
+      HashMap m = new HashMap();
+      m.put("EOF", true);
+      Tuple tuple = new Tuple(m);
+      return tuple;
+    } else {
+      HashMap m = new HashMap();
+      m.put("echo", echo);
+      Tuple tuple = new Tuple(m);
+      finished = true;
+      return tuple;
+    }
+  }
+
+  /** Return the stream sort - ie, the order in which records are returned */
+  public StreamComparator getStreamSort(){
+    return null;
+  }
+
+  public int getCost() {
+    return 0;
+  }
+
+
+}

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

@@ -4918,6 +4918,98 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     }
   }
 
+  @Test
+  public void testEchoStream() throws Exception {
+    String expr = "echo(hello world)";
+    ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    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);
+    String s = (String)tuples.get(0).get("echo");
+    assertTrue(s.equals("hello world"));
+
+    expr = "echo(\"hello world\")";
+    paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    solrStream = new SolrStream(url, paramsLoc);
+
+    solrStream.setStreamContext(context);
+    tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    s = (String)tuples.get(0).get("echo");
+    assertTrue(s.equals("hello world"));
+
+    expr = "echo(\"hello, world\")";
+    paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    solrStream = new SolrStream(url, paramsLoc);
+
+    solrStream.setStreamContext(context);
+    tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    s = (String)tuples.get(0).get("echo");
+    assertTrue(s.equals("hello, world"));
+
+    expr = "echo(\"hello, \\\"t\\\" world\")";
+    paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    solrStream = new SolrStream(url, paramsLoc);
+
+    solrStream.setStreamContext(context);
+    tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    s = (String)tuples.get(0).get("echo");
+
+    assertTrue(s.equals("hello, \"t\" world"));
+
+    expr = "parallel("+COLLECTIONORALIAS+", workers=2, sort=\"echo asc\", echo(\"hello, \\\"t\\\" world\"))";
+    paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    solrStream = new SolrStream(url, paramsLoc);
+
+    solrStream.setStreamContext(context);
+    tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 2);
+    s = (String)tuples.get(0).get("echo");
+    assertTrue(s.equals("hello, \"t\" world"));
+    s = (String)tuples.get(1).get("echo");
+    assertTrue(s.equals("hello, \"t\" world"));
+
+    expr = "echo(\"tuytuy iuyiuyi iuyiuyiu iuyiuyiuyiu iuyi iuyiyiuy iuyiuyiu iyiuyiu iyiuyiuyyiyiu yiuyiuyi" +
+        " yiuyiuyi yiuyiuuyiu yiyiuyiyiu iyiuyiuyiuiuyiu yiuyiuyi yiuyiy yiuiyiuiuy\")";
+    paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    solrStream = new SolrStream(url, paramsLoc);
+
+    solrStream.setStreamContext(context);
+    tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    s = (String)tuples.get(0).get("echo");
+
+    assertTrue(s.equals("tuytuy iuyiuyi iuyiuyiu iuyiuyiuyiu iuyi iuyiyiuy iuyiuyiu iyiuyiu iyiuyiuyyiyiu yiuyiuyi yiuyiuyi " +
+        "yiuyiuuyiu yiyiuyiyiu iyiuyiuyiuiuyiu yiuyiuyi yiuyiy yiuiyiuiuy"));
+
+
+
+  }
+
   @Test
   public void testConvertEvaluator() throws Exception {