1 files changed, 97 insertions, 0 deletions
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 000000000..8cad9f5e4
--- /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(";");
+    }
+
+}