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https://issues.apache.org/jira/browse/METAMODEL-18?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14156733#comment-14156733
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ASF GitHub Bot commented on METAMODEL-18:
-----------------------------------------
Github user kaspersorensen commented on a diff in the pull request:
https://github.com/apache/incubator-metamodel/pull/2#discussion_r18351184
--- Diff:
cassandra/src/main/java/org/apache/metamodel/cassandra/CassandraDBUtils.java ---
@@ -0,0 +1,80 @@
+/**
+ * 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.metamodel.cassandra;
+
+import com.datastax.driver.core.ColumnDefinitions;
+import com.datastax.driver.core.DataType;
+import org.apache.metamodel.data.DataSetHeader;
+import org.apache.metamodel.data.DefaultRow;
+import org.apache.metamodel.data.Row;
+import org.apache.metamodel.query.SelectItem;
+
+/**
+ * A utility class for Cassandra module.
+ *
+ * @author Alberto Rodriguez
+ */
+public class CassandraDBUtils {
+
+ /**
+ * Converts a Cassandra Row data object {@link
com.datastax.driver.core.Row}
+ * into MetaModel {@link org.apache.metamodel.data.Row}.
+ *
+ * @param dbObject a Cassandra object storing data.
+ * @param header a header describing the columns of the data stored.
+ * @return the MetaModel {@link org.apache.metamodel.data.Row} result
object.
+ */
+ public static Row toRow(com.datastax.driver.core.Row dbObject,
DataSetHeader header) {
+
+ if (dbObject == null) {
+ return null;
+ }
+
+ final int size = header.size();
+
+ final Object[] values = new Object[size];
+ for (int i = 0; i < values.length; i++) {
+ final SelectItem selectItem = header.getSelectItem(i);
+ final String key = selectItem.getColumn().getName();
+ values[i] = getColumnValue(key, dbObject);
+ }
+ return new DefaultRow(header, values);
+ }
+
+ private static Object getColumnValue(String columnName,
com.datastax.driver.core.Row row) {
+ ColumnDefinitions columns = row.getColumnDefinitions();
+ DataType columnType = columns.getType(columnName);
+ switch (columnType.getName()) {
+ case BIGINT: return row.getVarint(columnName);
+ case BOOLEAN: return row.getBool(columnName);
+ case DECIMAL: return row.getDecimal(columnName);
+ case DOUBLE: return row.getDouble(columnName);
+ case FLOAT: return row.getFloat(columnName);
+ case INET: return row.getInet(columnName);
+ case INT: return row.getInt(columnName);
+ case UUID: return row.getUUID(columnName);
--- End diff --
Here we return a UUID instance, while the ColumnType will be STRING. I
suggest we create a UUID ColumnType so that the value corresponds to the
expected type. The same principle applies probably to other column types ...
Set, Map, Inet and more.
> Cassandra DB support for MetaModel
> ----------------------------------
>
> Key: METAMODEL-18
> URL: https://issues.apache.org/jira/browse/METAMODEL-18
> Project: Metamodel
> Issue Type: New Feature
> Reporter: Kasper Sørensen
> Priority: Critical
>
> A new module for MetaModel, providing support for Cassandra.
> Note that Cassandra in many respects is similar to HBase, and we might run
> into some of the same issues. Check METAMODEL-13 for our HBase module JIRA
> issue.
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