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/**
* 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.csv;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectInputStream.GetField;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import org.apache.metamodel.schema.AbstractTable;
import org.apache.metamodel.schema.Column;
import org.apache.metamodel.schema.ColumnType;
import org.apache.metamodel.schema.MutableColumn;
import org.apache.metamodel.schema.Relationship;
import org.apache.metamodel.schema.Schema;
import org.apache.metamodel.schema.TableType;
import org.apache.metamodel.schema.naming.ColumnNamingContextImpl;
import org.apache.metamodel.schema.naming.ColumnNamingSession;
import org.apache.metamodel.schema.naming.ColumnNamingStrategy;
import org.apache.metamodel.util.FileHelper;
import org.apache.metamodel.util.LegacyDeserializationObjectInputStream;
import com.opencsv.CSVReader;
final class CsvTable extends AbstractTable {
private static final long serialVersionUID = 1L;
private final CsvSchema _schema;
private final String _tableName;
private List _columns;
/**
* Constructor for creating a new CSV table which has not yet been written.
*
* @param schema
* @param columnNames
*/
public CsvTable(CsvSchema schema, String tableName, List columnNames) {
this(schema, tableName);
_columns = buildColumns(columnNames);
}
/**
* Constructor for reading an existing CSV table.
*
* @param schema
*/
public CsvTable(CsvSchema schema, String tableName) {
_schema = schema;
_tableName = tableName;
}
@Override
public String getName() {
if (_tableName == null) {
// can only occur when deserializing legacy objects. Using the
// legacy MetaModel code for creating table name here.
String schemaName = _schema.getName();
return schemaName.substring(0, schemaName.length() - 4);
}
return _tableName;
}
@Override
public List getColumns() {
if (_columns == null) {
synchronized (this) {
if (_columns == null) {
_columns = buildColumns();
}
}
}
return _columns;
}
private List buildColumns() {
CSVReader reader = null;
try {
reader = _schema.getDataContext().createCsvReader(0);
final int columnNameLineNumber = _schema.getDataContext().getConfiguration().getColumnNameLineNumber();
for (int i = 1; i < columnNameLineNumber; i++) {
reader.readNext();
}
final List columnHeaders = Arrays.asList(Optional.ofNullable(reader.readNext()).orElse(new String[0]));
reader.close();
return buildColumns(columnHeaders);
} catch (IOException e) {
throw new IllegalStateException("Exception reading from resource: "
+ _schema.getDataContext().getResource().getName(), e);
} finally {
FileHelper.safeClose(reader);
}
}
private List buildColumns(final List columnNames) {
if (columnNames == null) {
return new ArrayList<>();
}
final CsvConfiguration configuration = _schema.getDataContext().getConfiguration();
final int columnNameLineNumber = configuration.getColumnNameLineNumber();
final boolean nullable = !configuration.isFailOnInconsistentRowLength();
final ColumnNamingStrategy columnNamingStrategy = configuration.getColumnNamingStrategy();
List columns = new ArrayList<>();
try (final ColumnNamingSession namingSession = columnNamingStrategy.startColumnNamingSession()) {
for (int i = 0; i < columnNames.size(); i++) {
final String intrinsicColumnName = columnNameLineNumber == CsvConfiguration.NO_COLUMN_NAME_LINE ? null
: columnNames.get(i);
final String columnName = namingSession.getNextColumnName(new ColumnNamingContextImpl(this,
intrinsicColumnName, i));
final Column column = new MutableColumn(columnName, ColumnType.STRING, this, i, null, null, nullable,
null, false, null);
columns.add(column);
}
}
return columns;
}
@Override
public Schema getSchema() {
return _schema;
}
@Override
public TableType getType() {
return TableType.TABLE;
}
@Override
public Collection getRelationships() {
return Collections.emptyList();
}
@Override
public String getRemarks() {
return null;
}
@Override
public String getQuote() {
return null;
}
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
final GetField getFields = stream.readFields();
Object columns = getFields.get("_columns", null);
if (columns instanceof Column[]) {
columns = Arrays. asList((Column[]) columns);
}
final Object schema = getFields.get("_schema", null);
final Object tableName = getFields.get("_tableName", null);
LegacyDeserializationObjectInputStream.setField(CsvTable.class, this, "_columns", columns);
LegacyDeserializationObjectInputStream.setField(CsvTable.class, this, "_schema", schema);
LegacyDeserializationObjectInputStream.setField(CsvTable.class, this, "_tableName", tableName);
}
}
