From 78d8d0c53552473f52c60cf098ce2fc6d6658365 Mon Sep 17 00:00:00 2001
From: Shalin Shekhar Mangar <shalin@apache.org>
Date: Fri, 13 Dec 2013 06:40:01 +0000
Subject: [PATCH] SOLR-3702: A 'concat' function query to support concatenation
 of Strings

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1550656 13f79535-47bb-0310-9956-ffa450edef68
---
 .../valuesource/ConcatenateFunction.java      | 75 +++++++++++++++++++
 solr/CHANGES.txt                              |  3 +
 .../apache/solr/search/ValueSourceParser.java |  7 ++
 .../search/function/TestFunctionQuery.java    | 20 +++++
 4 files changed, 105 insertions(+)
 create mode 100644 lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/ConcatenateFunction.java

diff --git a/lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/ConcatenateFunction.java b/lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/ConcatenateFunction.java
new file mode 100644
index 00000000000..08fa8e9ef41
--- /dev/null
+++ b/lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/ConcatenateFunction.java
@@ -0,0 +1,75 @@
+package org.apache.lucene.queries.function.valuesource;
+
+/*
+ * 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.
+ */
+
+
+import org.apache.lucene.index.AtomicReaderContext;
+import org.apache.lucene.queries.function.FunctionValues;
+import org.apache.lucene.queries.function.ValueSource;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A {@link ValueSource} implementation which concatenates existing string
+ * values from the provided ValueSources into one string.
+ */
+public class ConcatenateFunction extends MultiFunction {
+
+  public ConcatenateFunction(List<ValueSource> sources) {
+    super(sources);
+  }
+
+  @Override
+  protected String name() {
+    return "concat";
+  }
+
+  @Override
+  public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
+    return new Values(valsArr(sources, context, readerContext)) {
+
+      @Override
+      public String strVal(int doc) {
+        StringBuilder stringBuilder = new StringBuilder();
+        for (FunctionValues functionValues : valsArr) {
+          if (functionValues.exists(doc)) {
+            stringBuilder.append(functionValues.strVal(doc));
+          }
+        }
+        return stringBuilder.toString();
+      }
+
+      @Override
+      public Object objectVal(int doc) {
+        return strVal(doc);
+      }
+
+      @Override
+      public boolean exists(int doc) {
+        for (FunctionValues vals : valsArr) {
+          if (vals.exists(doc)) {
+            return true;
+          }
+        }
+        return false;
+      }
+    };
+  }
+}
diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 6687631b590..83a5cc79abd 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -127,6 +127,9 @@ New Features
 * SOLR-1871: The 'map' function query accepts a ValueSource as target and
   default value. (Chris Harris, shalin)
 
+* SOLR-3702: A 'concat' function query to support concatenation of Strings.
+  (Ted Strauss, Andrey Kudryavtsev via shalin)
+
 Bug Fixes
 ----------------------
 
diff --git a/solr/core/src/java/org/apache/solr/search/ValueSourceParser.java b/solr/core/src/java/org/apache/solr/search/ValueSourceParser.java
index 4c6cb941a3b..25c52489249 100644
--- a/solr/core/src/java/org/apache/solr/search/ValueSourceParser.java
+++ b/solr/core/src/java/org/apache/solr/search/ValueSourceParser.java
@@ -779,6 +779,13 @@ public abstract class ValueSourceParser implements NamedListInitializedPlugin {
       }
     });
 
+    addParser("concat", new ValueSourceParser() {
+      @Override
+      public ValueSource parse(FunctionQParser fp) throws SyntaxError {
+        return new ConcatenateFunction(fp.parseValueSourceList());
+      }
+    });
+
   }
 
   private static TInfo parseTerm(FunctionQParser fp) throws SyntaxError {
diff --git a/solr/core/src/test/org/apache/solr/search/function/TestFunctionQuery.java b/solr/core/src/test/org/apache/solr/search/function/TestFunctionQuery.java
index 1ed6dbcf4f3..2dbdde13da1 100644
--- a/solr/core/src/test/org/apache/solr/search/function/TestFunctionQuery.java
+++ b/solr/core/src/test/org/apache/solr/search/function/TestFunctionQuery.java
@@ -754,4 +754,24 @@ public class TestFunctionQuery extends SolrTestCaseJ4 {
     }
   }
 
+  public void testConcatFunction() {
+    clearIndex();
+
+    assertU(adoc("id", "1", "field1_t", "buzz", "field2_t", "word"));
+    assertU(adoc("id", "2", "field1_t", "1", "field2_t", "2","field4_t", "4"));
+    assertU(commit());
+
+    assertQ(req("q","id:1",
+        "fl","field:concat(field1_t,field2_t)"),
+        " //str[@name='field']='buzzword'");
+
+    assertQ(req("q","id:2",
+        "fl","field:concat(field1_t,field2_t, field3_t, field4_t)"),
+        " //str[@name='field']='124'");
+
+    assertQ(req("q","id:1",
+        "fl","field:def(concat(field3_t, field4_t), 'defValue')"),
+        " //str[@name='field']='defValue'");
+  }
+
 }