From ceb3c00bf03adb692208314c7e40f08b3750c934 Mon Sep 17 00:00:00 2001
From: Radu Cotescu <cotescu@adobe.com>
Date: Tue, 29 Sep 2015 15:04:13 +0200
Subject: [PATCH] OAK-3458 - Add support for the LIMIT and OFFSET SQL clauses

* added simple support for LIMIT and OFFSET in the main query
---
 .../apache/jackrabbit/oak/query/SQL2Parser.java    |  8 +++++++
 .../jackrabbit/oak/query/SQL2ParserTest.java       | 28 ++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/oak-core/src/main/java/org/apache/jackrabbit/oak/query/SQL2Parser.java b/oak-core/src/main/java/org/apache/jackrabbit/oak/query/SQL2Parser.java
index 4b6fa43..0f2d6dd 100644
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/query/SQL2Parser.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/query/SQL2Parser.java
@@ -158,6 +158,14 @@ public class SQL2Parser {
             read("BY");
             orderings = parseOrder();
         }
+        if (readIf("LIMIT")) {
+            PropertyValue limitValue = readString();
+            q.setLimit(limitValue.getValue(Type.LONG));
+        }
+        if (readIf("OFFSET")) {
+            PropertyValue limitValue = readString();
+            q.setOffset(limitValue.getValue(Type.LONG));
+        }
         if (!currentToken.isEmpty()) {
             throw getSyntaxError("<end>");
         }
diff --git a/oak-core/src/test/java/org/apache/jackrabbit/oak/query/SQL2ParserTest.java b/oak-core/src/test/java/org/apache/jackrabbit/oak/query/SQL2ParserTest.java
index 0a28376..ffd6d78 100644
--- a/oak-core/src/test/java/org/apache/jackrabbit/oak/query/SQL2ParserTest.java
+++ b/oak-core/src/test/java/org/apache/jackrabbit/oak/query/SQL2ParserTest.java
@@ -16,11 +16,13 @@
  */
 package org.apache.jackrabbit.oak.query;
 
+import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertTrue;
 import static org.apache.jackrabbit.JcrConstants.JCR_SYSTEM;
 import static org.apache.jackrabbit.oak.plugins.nodetype.NodeTypeConstants.JCR_NODE_TYPES;
 import static org.apache.jackrabbit.oak.plugins.nodetype.write.InitialContent.INITIAL_CONTENT;
 
+import java.lang.reflect.Field;
 import java.text.ParseException;
 
 import org.apache.jackrabbit.oak.query.xpath.XPathToSQL2Converter;
@@ -73,5 +75,31 @@ public class SQL2ParserTest {
         String token = "and b.[type] in('t1', 't2', 't3')";
         assertTrue(q.contains(token));
     }
+
+    @Test
+    public void testLimit() throws ParseException, NoSuchFieldException, IllegalAccessException {
+        Query q = p.parse("SELECT * FROM [nt:unstructured] AS s WHERE ISDESCENDANTNODE([/content/blog]) AND s.[sling:resourceType] = " +
+            "'a/b/c' LIMIT 10");
+        /**
+         * a bit hackish but the Query interface doesn't provide a getter for limit; however we do know that the SQL2Parser currently
+         * returns an instance of the {@link QueryImpl} class which has this long limit field
+         */
+        Field field = q.getClass().getDeclaredField("limit");
+        field.setAccessible(true);
+        assertEquals(10, field.getLong(q));
+    }
+
+    @Test
+    public void testOffset() throws ParseException, NoSuchFieldException, IllegalAccessException{
+        Query q = p.parse("SELECT * FROM [nt:unstructured] AS s WHERE ISDESCENDANTNODE([/content/blog]) AND s.[sling:resourceType] = " +
+            "'a/b/c' LIMIT 10 OFFSET 20");
+        /**
+         * a bit hackish but the Query interface doesn't provide a getter for limit; however we do know that the SQL2Parser currently
+         * returns an instance of the {@link QueryImpl} class which has this long offset field
+         */
+        Field field = q.getClass().getDeclaredField("offset");
+        field.setAccessible(true);
+        assertEquals(20, field.getLong(q));
+    }
     
 }
-- 
2.5.0