Refactoring: remove duplicate code with superclass

README.md

@@ -78,4 +78,6 @@ $ ./gradlew gem  # -t to watch change of files and rebuild continuously
 
 ## TEST
 
+```
 $ EMBULK_OUTPUT_DATABRICKS_TEST_CONFIG="example/test.yml" ./gradlew test # Create example/test.yml based on example/test.yml.example
+```

src/main/java/org/embulk/output/DatabricksOutputPlugin.java

@@ -1,8 +1,6 @@
 package org.embulk.output;
 
 import java.io.IOException;
-import java.sql.DatabaseMetaData;
-import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.*;
 import org.embulk.config.ConfigDiff;
@@ -171,86 +169,10 @@ protected void logConnectionProperties(String url, Properties props) {
     super.logConnectionProperties(url, maskedProps);
   }
 
-  // This is almost copy from AbstractJdbcOutputPlugin excepting validation of table exists in
-  // current schema
   public Optional<JdbcSchema> newJdbcSchemaFromTableIfExists(
       JdbcOutputConnection connection, TableIdentifier table) throws SQLException {
-    if (!connection.tableExists(table)) {
-      // DatabaseMetaData.getPrimaryKeys fails if table does not exist
-      return Optional.empty();
-    }
-
-    DatabricksOutputConnection conn = (DatabricksOutputConnection) connection;
-    DatabaseMetaData dbm = connection.getMetaData();
-    String escape = dbm.getSearchStringEscape();
-
-    ResultSet rs =
-        dbm.getPrimaryKeys(conn.getCatalogName(), table.getSchemaName(), table.getTableName());
-    final HashSet<String> primaryKeysBuilder = new HashSet<>();
-    try {
-      while (rs.next()) {
-        if (!((DatabricksOutputConnection) connection)
-            .isAvailableTableMetadataInConnection(rs, table)) {
-          continue;
-        }
-        primaryKeysBuilder.add(rs.getString("COLUMN_NAME"));
-      }
-    } finally {
-      rs.close();
-    }
-    final Set<String> primaryKeys = Collections.unmodifiableSet(primaryKeysBuilder);
-
-    final ArrayList<JdbcColumn> builder = new ArrayList<>();
-    // NOTE: Columns of TIMESTAMP_NTZ, INTERVAL are not included in getColumns result.
-    // This cause runtime sql exception when copy into.
-    // (probably because of unsupported in databricks jdbc)
-    // https://docs.databricks.com/en/sql/language-manual/data-types/interval-type.html
-    // https://docs.databricks.com/en/sql/language-manual/data-types/timestamp-ntz-type.html#notes
-    rs =
-        dbm.getColumns(
-            JdbcUtils.escapeSearchString(conn.getCatalogName(), escape),
-            JdbcUtils.escapeSearchString(table.getSchemaName(), escape),
-            JdbcUtils.escapeSearchString(table.getTableName(), escape),
-            null);
-    try {
-      while (rs.next()) {
-        if (!((DatabricksOutputConnection) connection)
-            .isAvailableTableMetadataInConnection(rs, table)) {
-          continue;
-        }
-        String columnName = rs.getString("COLUMN_NAME");
-        String simpleTypeName = rs.getString("TYPE_NAME").toUpperCase(Locale.ENGLISH);
-        boolean isUniqueKey = primaryKeys.contains(columnName);
-        int sqlType = rs.getInt("DATA_TYPE");
-        int colSize = rs.getInt("COLUMN_SIZE");
-        int decDigit = rs.getInt("DECIMAL_DIGITS");
-        if (rs.wasNull()) {
-          decDigit = -1;
-        }
-        int charOctetLength = rs.getInt("CHAR_OCTET_LENGTH");
-        boolean isNotNull = "NO".equals(rs.getString("IS_NULLABLE"));
-        // rs.getString("COLUMN_DEF") // or null  // TODO
-        builder.add(
-            JdbcColumn.newGenericTypeColumn(
-                columnName,
-                sqlType,
-                simpleTypeName,
-                colSize,
-                decDigit,
-                charOctetLength,
-                isNotNull,
-                isUniqueKey));
-        // We can't get declared column name using JDBC API.
-        // Subclasses need to overwrite it.
-      }
-    } finally {
-      rs.close();
-    }
-    final List<JdbcColumn> columns = Collections.unmodifiableList(builder);
-    if (columns.isEmpty()) {
-      return Optional.empty();
-    } else {
-      return Optional.of(new JdbcSchema(columns));
-    }
+    return super.newJdbcSchemaFromTableIfExists(
+        connection,
+        ((DatabricksOutputConnection) connection).currentConnectionTableIdentifier(table));
   }
 }

src/main/java/org/embulk/output/databricks/DatabricksOutputConnection.java

@@ -42,58 +42,21 @@ protected void executeUseStatement(String sql) throws SQLException {
   // This is almost copy from JdbcOutputConnection excepting validation of table exists in current
   // schema
   public boolean tableExists(TableIdentifier table) throws SQLException {
-    try (ResultSet rs =
-        connection
-            .getMetaData()
-            .getTables(catalogName, table.getSchemaName(), table.getTableName(), null)) {
-      while (rs.next()) {
-        if (isAvailableTableMetadataInConnection(rs, table)) {
-          return true;
-        }
-      }
-    }
-    return false;
+    return super.tableExists(currentConnectionTableIdentifier(table));
   }
 
-  public boolean isAvailableTableMetadataInConnection(ResultSet rs, TableIdentifier tableIdentifier)
-      throws SQLException {
-    // If unchecked, tables in other catalogs may appear to exist.
-    // This is because the base embulk jdbc plugin's tableIdentifier.getDatabase() is often returns
-    // null
-    // and one Databricks connection has multiple available catalogs　(databases).
-
-    // NOTE: maybe this logic is not necessary anymore after this PR:
-    //    https://github.com/trocco-io/embulk-output-databricks/pull/11
-    // But I'm not sure, so I'll keep it for now.
-
-    if (tableIdentifier.getDatabase() == null) {
-      logger.trace("tableIdentifier.getDatabase() == null, check by instance variable");
-      if (!rs.getString("TABLE_CAT").equalsIgnoreCase(catalogName)) {
-        return false;
-      }
-    }
-    if (tableIdentifier.getSchemaName() == null) {
-      logger.trace("tableIdentifier.getSchemaName() == null, check by instance variable");
-      if (!rs.getString("TABLE_SCHEM").equalsIgnoreCase(schemaName)) {
-        return false;
-      }
-    }
-
-    if (tableIdentifier.getDatabase() != null
-        && !tableIdentifier.getDatabase().equalsIgnoreCase(catalogName)) {
-      logger.error(
-          String.format(
-              "tableIdentifier.getSchemaName() != instance variable. (%s, %s)",
-              tableIdentifier.getDatabase(), catalogName));
-    }
-    if (tableIdentifier.getSchemaName() != null
-        && !tableIdentifier.getSchemaName().equalsIgnoreCase(schemaName)) {
-      logger.error(
-          String.format(
-              "tableIdentifier.getSchemaName() != instance variable. (%s, %s)",
-              tableIdentifier.getSchemaName(), schemaName));
-    }
-    return true;
+  public TableIdentifier currentConnectionTableIdentifier(TableIdentifier tableIdentifier) {
+    // Caution:
+    // JdbcOutputPlugin sometimes uses tableIdentifier whose database variable is null,
+    // which causes unexpected DatabaseMetaData behavior in AbstractJdbcOutputPlugin.
+    // For example, getTables and getColumns search in all catalogs,
+    // not just the one specified by the connection's default value,
+    // and can't search in schemas with multibyte name.
+    // So, if tableIdentifier database variable is null, it will set the connection's default value.
+    return new TableIdentifier(
+        tableIdentifier.getDatabase() != null ? tableIdentifier.getDatabase() : catalogName,
+        tableIdentifier.getSchemaName() != null ? tableIdentifier.getSchemaName() : schemaName,
+        tableIdentifier.getTableName());
   }
 
   @Override
@@ -299,8 +262,4 @@ private String buildColumns(JdbcSchema schema, String prefix) {
     }
     return sb.toString();
   }
-
-  public String getCatalogName() {
-    return catalogName;
-  }
 }