/**
* 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.hadoop.hive.serde2;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.serde.serdeConstants;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.StructField;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import java.io.CharArrayReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;
import au.com.bytecode.opencsv.CSVReader;
import au.com.bytecode.opencsv.CSVWriter;
/**
* OpenCSVSerde use opencsv to deserialize CSV format.
* Users can specify custom separator, quote or escape characters. And the default separator(\),
* quote("), and escape characters(\) are the same as the opencsv library.
*
*/
@SerDeSpec(schemaProps = {
serdeConstants.LIST_COLUMNS,
OpenCSVSerde.SEPARATORCHAR, OpenCSVSerde.QUOTECHAR, OpenCSVSerde.ESCAPECHAR})
public final class OpenCSVSerde extends AbstractSerDe {
public static final Log LOG = LogFactory.getLog(OpenCSVSerde.class.getName());
private ObjectInspector inspector;
private String[] outputFields;
private int numCols;
private List<String> row;
private char separatorChar;
private char quoteChar;
private char escapeChar;
public static final String SEPARATORCHAR = "separatorChar";
public static final String QUOTECHAR = "quoteChar";
public static final String ESCAPECHAR = "escapeChar";
@Override
public void initialize(final Configuration conf, final Properties tbl) throws SerDeException {
final List<String> columnNames = Arrays.asList(tbl.getProperty(serdeConstants.LIST_COLUMNS)
.split(","));
numCols = columnNames.size();
final List<ObjectInspector> columnOIs = new ArrayList<ObjectInspector>(numCols);
for (int i = 0; i < numCols; i++) {
columnOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
}
inspector = ObjectInspectorFactory.getStandardStructObjectInspector(columnNames, columnOIs);
outputFields = new String[numCols];
row = new ArrayList<String>(numCols);
for (int i = 0; i < numCols; i++) {
row.add(null);
}
separatorChar = getProperty(tbl, SEPARATORCHAR, CSVWriter.DEFAULT_SEPARATOR);
quoteChar = getProperty(tbl, QUOTECHAR, CSVWriter.DEFAULT_QUOTE_CHARACTER);
escapeChar = getProperty(tbl, ESCAPECHAR, CSVWriter.DEFAULT_ESCAPE_CHARACTER);
}
private char getProperty(final Properties tbl, final String property, final char def) {
final String val = tbl.getProperty(property);
if (val != null) {
return val.charAt(0);
}
return def;
}
@Override
public Writable serialize(Object obj, ObjectInspector objInspector) throws SerDeException {
final StructObjectInspector outputRowOI = (StructObjectInspector) objInspector;
final List<? extends StructField> outputFieldRefs = outputRowOI.getAllStructFieldRefs();
if (outputFieldRefs.size() != numCols) {
throw new SerDeException("Cannot serialize the object because there are "
+ outputFieldRefs.size() + " fields but the table has " + numCols + " columns.");
}
// Get all data out.
for (int c = 0; c < numCols; c++) {
final Object field = outputRowOI.getStructFieldData(obj, outputFieldRefs.get(c));
final ObjectInspector fieldOI = outputFieldRefs.get(c).getFieldObjectInspector();
// The data must be of type String
final StringObjectInspector fieldStringOI = (StringObjectInspector) fieldOI;
// Convert the field to Java class String, because objects of String type
// can be stored in String, Text, or some other classes.
outputFields[c] = fieldStringOI.getPrimitiveJavaObject(field);
}
final StringWriter writer = new StringWriter();
final CSVWriter csv = newWriter(writer, separatorChar, quoteChar, escapeChar);
try {
csv.writeNext(outputFields);
csv.close();
return new Text(writer.toString());
} catch (final IOException ioe) {
throw new SerDeException(ioe);
}
}
@Override
public Object deserialize(final Writable blob) throws SerDeException {
Text rowText = (Text) blob;
CSVReader csv = null;
try {
csv = newReader(new CharArrayReader(rowText.toString().toCharArray()), separatorChar,
quoteChar, escapeChar);
final String[] read = csv.readNext();
for (int i = 0; i < numCols; i++) {
if (read != null && i < read.length) {
row.set(i, read[i]);
} else {
row.set(i, null);
}
}
return row;
} catch (final Exception e) {
throw new SerDeException(e);
} finally {
if (csv != null) {
try {
csv.close();
} catch (final Exception e) {
LOG.error("fail to close csv writer ", e);
}
}
}
}
private CSVReader newReader(final Reader reader, char separator, char quote, char escape) {
// CSVReader will throw an exception if any of separator, quote, or escape is the same, but
// the CSV format specifies that the escape character and quote char are the same... very weird
if (CSVWriter.DEFAULT_ESCAPE_CHARACTER == escape) {
return new CSVReader(reader, separator, quote);
} else {
return new CSVReader(reader, separator, quote, escape);
}
}
private CSVWriter newWriter(final Writer writer, char separator, char quote, char escape) {
if (CSVWriter.DEFAULT_ESCAPE_CHARACTER == escape) {
return new CSVWriter(writer, separator, quote, "");
} else {
return new CSVWriter(writer, separator, quote, escape, "");
}
}
@Override
public ObjectInspector getObjectInspector() throws SerDeException {
return inspector;
}
@Override
public Class<? extends Writable> getSerializedClass() {
return Text.class;
}
@Override
public SerDeStats getSerDeStats() {
return null;
}
}