Temp Table Creation improvements

- extracted methods for more generic temp table creation
- optimized
- added perf test on use case that depends on temp table creation
- had some doubts about stopwatch use in recent tests, but was all OK, just renamed some

Issue-ID: CPS-1422
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>
Change-Id: I22cabb9b0ba1b0aa8576a2d756d77af46eebc1b0

4 files changed, 111 insertions, 43 deletions

diff --git a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceQuery.java b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceQuery.java
index 5e4de7fec4..00e53aa00f 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceQuery.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceQuery.java
@@ -28,6 +28,5 @@ import org.onap.cps.spi.model.ModuleReference;
  */
 public interface ModuleReferenceQuery {
 
-    Collection<ModuleReference> identifyNewModuleReferences(
-        final Collection<ModuleReference> moduleReferencesToCheck);
+    Collection<ModuleReference> identifyNewModuleReferences(final Collection<ModuleReference> moduleReferencesToCheck);
 }
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepository.java b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepository.java
index f70e218373..ef701bc7dc 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepository.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepository.java
@@ -20,16 +20,10 @@
 
 package org.onap.cps.spi.repository;
 
-import java.util.Collection;
 import org.onap.cps.spi.entities.YangResourceEntity;
-import org.onap.cps.spi.model.ModuleReference;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface ModuleReferenceRepository extends JpaRepository<YangResourceEntity, Long>, ModuleReferenceQuery {
+public interface ModuleReferenceRepository extends JpaRepository<YangResourceEntity, Long>, ModuleReferenceQuery {}
 
-    Collection<ModuleReference> identifyNewModuleReferences(
-        final Collection<ModuleReference> moduleReferencesToCheck);
-
-}
\ No newline at end of file
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepositoryImpl.java b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepositoryImpl.java
index 681bbcddec..48982d51ff 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepositoryImpl.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/repository/ModuleReferenceRepositoryImpl.java
@@ -23,8 +23,8 @@ package org.onap.cps.spi.repository;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
-import java.util.UUID;
 import javax.persistence.EntityManager;
 import javax.persistence.PersistenceContext;
 import lombok.AllArgsConstructor;
@@ -41,6 +41,8 @@ public class ModuleReferenceRepositoryImpl implements ModuleReferenceQuery {
     @PersistenceContext
     private EntityManager entityManager;
 
+    private TempTableCreator tempTableCreator;
+
     @Override
     @SneakyThrows
     public Collection<ModuleReference> identifyNewModuleReferences(
@@ -50,42 +52,18 @@ public class ModuleReferenceRepositoryImpl implements ModuleReferenceQuery {
             return Collections.emptyList();
         }
 
-        final String tempTableName = "moduleReferencesToCheckTemp"
-                + UUID.randomUUID().toString().replace("-", "");
-
-        createTemporaryTable(tempTableName);
-        insertDataIntoTable(tempTableName, moduleReferencesToCheck);
-
-        return identifyNewModuleReferencesForCmHandle(tempTableName);
-    }
-
-    private void createTemporaryTable(final String tempTableName) {
-        final StringBuilder sqlStringBuilder = new StringBuilder("CREATE TEMPORARY TABLE " + tempTableName + "(");
-        sqlStringBuilder.append(" id INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,");
-        sqlStringBuilder.append(" module_name varchar NOT NULL,");
-        sqlStringBuilder.append(" revision varchar NOT NULL");
-        sqlStringBuilder.append(");");
-
-        entityManager.createNativeQuery(sqlStringBuilder.toString()).executeUpdate();
-    }
-
-    private void insertDataIntoTable(final String tempTableName, final Collection<ModuleReference> moduleReferences) {
-        final StringBuilder sqlStringBuilder = new StringBuilder("INSERT INTO  " + tempTableName);
-        sqlStringBuilder.append(" (module_name, revision) ");
-        sqlStringBuilder.append(" VALUES ");
-
-        for (final ModuleReference moduleReference : moduleReferences) {
-            sqlStringBuilder.append("('");
-            sqlStringBuilder.append(moduleReference.getModuleName());
-            sqlStringBuilder.append("', '");
-            sqlStringBuilder.append(moduleReference.getRevision());
-            sqlStringBuilder.append("'),");
+        final Collection<List<String>> sqlData = new HashSet<>(moduleReferencesToCheck.size());
+        for (final ModuleReference moduleReference : moduleReferencesToCheck) {
+            final List<String> row = new ArrayList<>(2);
+            row.add(moduleReference.getModuleName());
+            row.add(moduleReference.getRevision());
+            sqlData.add(row);
         }
 
-        // replace last ',' with ';'
-        sqlStringBuilder.replace(sqlStringBuilder.length() - 1, sqlStringBuilder.length(), ";");
+        final String tempTableName = tempTableCreator.createTemporaryTable(
+            "moduleReferencesToCheckTemp", sqlData, "module_name", "revision");
 
-        entityManager.createNativeQuery(sqlStringBuilder.toString()).executeUpdate();
+        return identifyNewModuleReferencesForCmHandle(tempTableName);
     }
 
     private Collection<ModuleReference> identifyNewModuleReferencesForCmHandle(final String tempTableName) {
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/repository/TempTableCreator.java b/cps-ri/src/main/java/org/onap/cps/spi/repository/TempTableCreator.java
new file mode 100644
index 0000000000..8cad9f5e4c
--- /dev/null
+++ b/cps-ri/src/main/java/org/onap/cps/spi/repository/TempTableCreator.java
@@ -0,0 +1,97 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2022 Nordix Foundation.
+ * ================================================================================
+ * Licensed 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.spi.repository;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.UUID;
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import lombok.AllArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
+
+@Slf4j
+@Transactional
+@AllArgsConstructor
+@Component
+public class TempTableCreator {
+
+    @PersistenceContext
+    private EntityManager entityManager;
+
+    /**
+     * Create a uniquely named temporary table.
+     *
+     * @param prefix      prefix for the table name (so you can recognize it)
+     * @param sqlData     data to insert (strings only) the inner List present a row of data
+     * @param columnNames column names (in same order as data in rows in sqlData)
+     * @return a unique temporary table name with given prefix
+     */
+    public String createTemporaryTable(final String prefix,
+                                       final Collection<List<String>> sqlData,
+                                       final String... columnNames) {
+        final String tempTableName = prefix + UUID.randomUUID().toString().replace("-", "");
+        final StringBuilder sqlStringBuilder = new StringBuilder("CREATE TEMPORARY TABLE ");
+        sqlStringBuilder.append(tempTableName);
+        defineColumns(sqlStringBuilder, columnNames);
+        insertData(sqlStringBuilder, tempTableName, columnNames, sqlData);
+        entityManager.createNativeQuery(sqlStringBuilder.toString()).executeUpdate();
+        return tempTableName;
+    }
+
+    private static void defineColumns(final StringBuilder sqlStringBuilder, final String[] columnNames) {
+        sqlStringBuilder.append('(');
+        final Iterator<String> it = Arrays.stream(columnNames).iterator();
+        while (it.hasNext()) {
+            final String columnName = it.next();
+            sqlStringBuilder.append(" ");
+            sqlStringBuilder.append(columnName);
+            sqlStringBuilder.append(" varchar NOT NULL");
+            if (it.hasNext()) {
+                sqlStringBuilder.append(",");
+            }
+        }
+        sqlStringBuilder.append(");");
+    }
+
+    private static void insertData(final StringBuilder sqlStringBuilder,
+                                   final String tempTableName,
+                                   final String[] columnNames,
+                                   final Collection<List<String>> sqlData) {
+        final Collection<String> sqlInserts = new HashSet<>(sqlData.size());
+        for (final Collection<String> row : sqlData) {
+            sqlInserts.add("('" + String.join("','", row) + "')");
+        }
+        sqlStringBuilder.append("INSERT INTO ");
+        sqlStringBuilder.append(tempTableName);
+        sqlStringBuilder.append(" (");
+        sqlStringBuilder.append(String.join(",", columnNames));
+        sqlStringBuilder.append(") VALUES ");
+        sqlStringBuilder.append(String.join(",", sqlInserts));
+        sqlStringBuilder.append(";");
+    }
+
+}