/**
* 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.hcatalog.data;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.hive.serde2.SerDeException;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.StructField;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hcatalog.common.HCatException;
import org.apache.hcatalog.data.schema.HCatSchema;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* An implementation of HCatRecord that wraps an Object returned by a SerDe
* and an ObjectInspector. This delays deserialization of unused columns.
*/
public class LazyHCatRecord extends HCatRecord {
public static final Logger LOG = LoggerFactory.getLogger(LazyHCatRecord.class.getName());
private Object wrappedObject;
private StructObjectInspector soi;
@Override
public Object get(int fieldNum) {
try {
StructField fref = soi.getAllStructFieldRefs().get(fieldNum);
return HCatRecordSerDe.serializeField(
soi.getStructFieldData(wrappedObject, fref),
fref.getFieldObjectInspector());
} catch (SerDeException e) {
throw new IllegalStateException("SerDe Exception deserializing",e);
}
}
@Override
public List<Object> getAll() {
List<Object> r = new ArrayList<Object>(this.size());
for (int i = 0; i < this.size(); i++){
r.add(i, get(i));
}
return r;
}
@Override
public void set(int fieldNum, Object value) {
throw new UnsupportedOperationException("not allowed to run set() on LazyHCatRecord");
}
@Override
public int size() {
return soi.getAllStructFieldRefs().size();
}
@Override
public void readFields(DataInput in) throws IOException {
throw new UnsupportedOperationException("LazyHCatRecord is intended to wrap"
+ " an object/object inspector as a HCatRecord "
+ "- it does not need to be read from DataInput.");
}
@Override
public void write(DataOutput out) throws IOException {
throw new UnsupportedOperationException("LazyHCatRecord is intended to wrap"
+ " an object/object inspector as a HCatRecord "
+ "- it does not need to be written to a DataOutput.");
}
@Override
public Object get(String fieldName, HCatSchema recordSchema) throws HCatException {
int idx = recordSchema.getPosition(fieldName);
return get(idx);
}
@Override
public void set(String fieldName, HCatSchema recordSchema, Object value) throws HCatException {
throw new UnsupportedOperationException("not allowed to run set() on LazyHCatRecord");
}
@Override
public void remove(int idx) throws HCatException {
throw new UnsupportedOperationException("not allowed to run remove() on LazyHCatRecord");
}
@Override
public void copy(HCatRecord r) throws HCatException {
throw new UnsupportedOperationException("not allowed to run copy() on LazyHCatRecord");
}
public LazyHCatRecord(Object wrappedObject, ObjectInspector oi) throws Exception {
if (oi.getCategory() != Category.STRUCT) {
throw new SerDeException(getClass().toString() +
" can only make a lazy hcat record from " +
"objects of struct types, but we got: " + oi.getTypeName());
}
this.soi = (StructObjectInspector)oi;
this.wrappedObject = wrappedObject;
}
@Override
public String toString(){
StringBuilder sb = new StringBuilder();
for(int i = 0; i< size() ; i++) {
sb.append(get(i)+"\t");
}
return sb.toString();
}
/**
* Convert this LazyHCatRecord to a DefaultHCatRecord. This is required
* before you can write out a record via write.
* @return an HCatRecord that can be serialized
* @throws HCatException
*/
public HCatRecord getWritable() throws HCatException {
DefaultHCatRecord d = new DefaultHCatRecord();
d.copy(this);
return d;
}
}