/**
* 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.contrib.serde2;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.MissingFormatArgumentException;
import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.serde.Constants;
import org.apache.hadoop.hive.serde2.SerDe;
import org.apache.hadoop.hive.serde2.SerDeException;
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.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
/**
* RegexSerDe uses regular expression (regex) to serialize/deserialize.
*
* It can deserialize the data using regex and extracts groups as columns. It
* can also serialize the row object using a format string.
*
* In deserialization stage, if a row does not match the regex, then all columns
* in the row will be NULL. If a row matches the regex but has less than
* expected groups, the missing groups will be NULL. If a row matches the regex
* but has more than expected groups, the additional groups are just ignored.
*
* In serialization stage, it uses java string formatter to format the columns
* into a row. If the output type of the column in a query is not a string, it
* will be automatically converted to String by Hive.
*
* For the format of the format String, please refer to {@link http
* ://java.sun.com/j2se/1.5.0/docs/api/java/util/Formatter.html#syntax}
*
* NOTE: Obviously, all columns have to be strings. Users can use
* "CAST(a AS INT)" to convert columns to other types.
*
* NOTE: This implementation is using String, and javaStringObjectInspector. A
* more efficient implementation should use UTF-8 encoded Text and
* writableStringObjectInspector. We should switch to that when we have a UTF-8
* based Regex library.
*/
public class RegexSerDe implements SerDe {
public static final Log LOG = LogFactory.getLog(RegexSerDe.class.getName());
int numColumns;
String inputRegex;
String outputFormatString;
Pattern inputPattern;
StructObjectInspector rowOI;
ArrayList<String> row;
@Override
public void initialize(Configuration conf, Properties tbl)
throws SerDeException {
// We can get the table definition from tbl.
// Read the configuration parameters
inputRegex = tbl.getProperty("input.regex");
outputFormatString = tbl.getProperty("output.format.string");
String columnNameProperty = tbl.getProperty(Constants.LIST_COLUMNS);
String columnTypeProperty = tbl.getProperty(Constants.LIST_COLUMN_TYPES);
boolean inputRegexIgnoreCase = "true".equalsIgnoreCase(tbl
.getProperty("input.regex.case.insensitive"));
// Parse the configuration parameters
if (inputRegex != null) {
inputPattern = Pattern.compile(inputRegex, Pattern.DOTALL
+ (inputRegexIgnoreCase ? Pattern.CASE_INSENSITIVE : 0));
} else {
inputPattern = null;
}
List<String> columnNames = Arrays.asList(columnNameProperty.split(","));
List<TypeInfo> columnTypes = TypeInfoUtils
.getTypeInfosFromTypeString(columnTypeProperty);
assert columnNames.size() == columnTypes.size();
numColumns = columnNames.size();
// All columns have to be of type STRING.
for (int c = 0; c < numColumns; c++) {
if (!columnTypes.get(c).equals(TypeInfoFactory.stringTypeInfo)) {
throw new SerDeException(getClass().getName()
+ " only accepts string columns, but column[" + c + "] named "
+ columnNames.get(c) + " has type " + columnTypes.get(c));
}
}
// Constructing the row ObjectInspector:
// The row consists of some string columns, each column will be a java
// String object.
List<ObjectInspector> columnOIs = new ArrayList<ObjectInspector>(
columnNames.size());
for (int c = 0; c < numColumns; c++) {
columnOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
}
// StandardStruct uses ArrayList to store the row.
rowOI = ObjectInspectorFactory.getStandardStructObjectInspector(
columnNames, columnOIs);
// Constructing the row object, etc, which will be reused for all rows.
row = new ArrayList<String>(numColumns);
for (int c = 0; c < numColumns; c++) {
row.add(null);
}
outputFields = new Object[numColumns];
outputRowText = new Text();
}
@Override
public ObjectInspector getObjectInspector() throws SerDeException {
return rowOI;
}
@Override
public Class<? extends Writable> getSerializedClass() {
return Text.class;
}
// Number of rows not matching the regex
long unmatchedRows = 0;
long nextUnmatchedRows = 1;
// Number of rows that match the regex but have missing groups.
long partialMatchedRows = 0;
long nextPartialMatchedRows = 1;
long getNextNumberToDisplay(long now) {
return now * 10;
}
@Override
public Object deserialize(Writable blob) throws SerDeException {
if (inputPattern == null) {
throw new SerDeException(
"This table does not have serde property \"input.regex\"!");
}
Text rowText = (Text) blob;
Matcher m = inputPattern.matcher(rowText.toString());
// If do not match, ignore the line, return a row with all nulls.
if (!m.matches()) {
unmatchedRows++;
if (unmatchedRows >= nextUnmatchedRows) {
nextUnmatchedRows = getNextNumberToDisplay(nextUnmatchedRows);
// Report the row
LOG.warn("" + unmatchedRows + " unmatched rows are found: " + rowText);
}
return null;
}
// Otherwise, return the row.
for (int c = 0; c < numColumns; c++) {
try {
row.set(c, m.group(c + 1));
} catch (RuntimeException e) {
partialMatchedRows++;
if (partialMatchedRows >= nextPartialMatchedRows) {
nextPartialMatchedRows = getNextNumberToDisplay(nextPartialMatchedRows);
// Report the row
LOG.warn("" + partialMatchedRows
+ " partially unmatched rows are found, " + " cannot find group "
+ c + ": " + rowText);
}
row.set(c, null);
}
}
return row;
}
Object[] outputFields;
Text outputRowText;
@Override
public Writable serialize(Object obj, ObjectInspector objInspector)
throws SerDeException {
if (outputFormatString == null) {
throw new SerDeException(
"Cannot write data into table because \"output.format.string\""
+ " is not specified in serde properties of the table.");
}
// Get all the fields out.
// NOTE: The correct way to get fields out of the row is to use
// objInspector.
// The obj can be a Java ArrayList, or a Java class, or a byte[] or
// whatever.
// The only way to access the data inside the obj is through
// ObjectInspector.
StructObjectInspector outputRowOI = (StructObjectInspector) objInspector;
List<? extends StructField> outputFieldRefs = outputRowOI
.getAllStructFieldRefs();
if (outputFieldRefs.size() != numColumns) {
throw new SerDeException("Cannot serialize the object because there are "
+ outputFieldRefs.size() + " fields but the table has " + numColumns
+ " columns.");
}
// Get all data out.
for (int c = 0; c < numColumns; c++) {
Object field = outputRowOI
.getStructFieldData(obj, outputFieldRefs.get(c));
ObjectInspector fieldOI = outputFieldRefs.get(c)
.getFieldObjectInspector();
// The data must be of type String
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);
}
// Format the String
String outputRowString = null;
try {
outputRowString = String.format(outputFormatString, outputFields);
} catch (MissingFormatArgumentException e) {
throw new SerDeException("The table contains " + numColumns
+ " columns, but the outputFormatString is asking for more.", e);
}
outputRowText.set(outputRowString);
return outputRowText;
}
}