/*
* Copyright © 2014 Cask Data, Inc.
*
* Licensed 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 co.cask.cdap.hive.objectinspector;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.SettableStructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.StructField;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* ListStructObjectInspector works on struct data that is stored as a Java List
* or Java Array object. Basically, the fields are stored sequentially in the
* List object.
*
* The names of the struct fields and the internal structure of the struct
* fields are specified in the ctor of the StructObjectInspector.
*
* Always use the ObjectInspectorFactory to create new ObjectInspector objects,
* instead of directly creating an instance of this class.
*/
public class StandardStructObjectInspector extends
SettableStructObjectInspector {
public static final Log LOG = LogFactory.getLog(StandardStructObjectInspector.class.getName());
/**
* MyField.
*
*/
protected static class MyField implements StructField {
protected int fieldID;
protected String fieldName;
protected ObjectInspector fieldObjectInspector;
protected String fieldComment;
public MyField(int fieldID, String fieldName,
ObjectInspector fieldObjectInspector) {
this.fieldID = fieldID;
this.fieldName = fieldName.toLowerCase();
this.fieldObjectInspector = fieldObjectInspector;
}
public MyField(int fieldID, String fieldName,
ObjectInspector fieldObjectInspector, String fieldComment) {
this(fieldID, fieldName, fieldObjectInspector);
this.fieldComment = fieldComment;
}
public int getFieldID() {
return fieldID;
}
public String getFieldName() {
return fieldName;
}
public ObjectInspector getFieldObjectInspector() {
return fieldObjectInspector;
}
public String getFieldComment() {
return fieldComment;
}
@Override
public String toString() {
return "" + fieldID + ":" + fieldName;
}
}
protected List<MyField> fields;
public String getTypeName() {
return ObjectInspectorUtils.getStandardStructTypeName(this);
}
/**
* Call ObjectInspectorFactory.getStandardListObjectInspector instead.
*/
protected StandardStructObjectInspector(List<String> structFieldNames,
List<ObjectInspector> structFieldObjectInspectors) {
init(structFieldNames, structFieldObjectInspectors, null);
}
/**
* Call ObjectInspectorFactory.getStandardListObjectInspector instead.
*/
protected StandardStructObjectInspector(List<String> structFieldNames,
List<ObjectInspector> structFieldObjectInspectors,
List<String> structFieldComments) {
init(structFieldNames, structFieldObjectInspectors, structFieldComments);
}
protected void init(List<String> structFieldNames,
List<ObjectInspector> structFieldObjectInspectors,
List<String> structFieldComments) {
assert (structFieldNames.size() == structFieldObjectInspectors.size());
assert (structFieldComments == null ||
(structFieldNames.size() == structFieldComments.size()));
fields = new ArrayList<>(structFieldNames.size());
for (int i = 0; i < structFieldNames.size(); i++) {
fields.add(new MyField(i, structFieldNames.get(i),
structFieldObjectInspectors.get(i),
structFieldComments == null ? null : structFieldComments.get(i)));
}
}
protected StandardStructObjectInspector(List<StructField> fields) {
init(fields);
}
protected void init(List<StructField> fields) {
this.fields = new ArrayList<>(fields.size());
for (int i = 0; i < fields.size(); i++) {
this.fields.add(new MyField(i, fields.get(i).getFieldName(), fields
.get(i).getFieldObjectInspector()));
}
}
public final Category getCategory() {
return Category.STRUCT;
}
// Without Data
@Override
public StructField getStructFieldRef(String fieldName) {
return ObjectInspectorUtils.getStandardStructFieldRef(fieldName, fields);
}
@Override
public List<? extends StructField> getAllStructFieldRefs() {
return fields;
}
boolean warned = false;
// With Data
@Override
@SuppressWarnings("unchecked")
public Object getStructFieldData(Object data, StructField fieldRef) {
if (data == null) {
return null;
}
// We support both List<Object> and Object[]
// so we have to do differently.
boolean isArray = !(data instanceof List);
if (!isArray && !(data instanceof List)) {
return data;
}
int listSize = (isArray ? ((Object[]) data).length : ((List<Object>) data)
.size());
MyField f = (MyField) fieldRef;
if (fields.size() != listSize && !warned) {
// TODO: remove this
warned = true;
LOG.warn("Trying to access " + fields.size()
+ " fields inside a list of " + listSize + " elements: "
+ (isArray ? Arrays.asList((Object[]) data) : (List<Object>) data));
LOG.warn("ignoring similar errors.");
}
int fieldID = f.getFieldID();
assert (fieldID >= 0 && fieldID < fields.size());
if (fieldID >= listSize) {
return null;
} else if (isArray) {
return ((Object[]) data)[fieldID];
} else {
return ((List<Object>) data).get(fieldID);
}
}
@Override
@SuppressWarnings("unchecked")
public List<Object> getStructFieldsDataAsList(Object data) {
if (data == null) {
return null;
}
// We support both List<Object> and Object[]
// so we have to do differently.
if (!(data instanceof List)) {
data = Arrays.asList((Object[]) data);
}
List<Object> list = (List<Object>) data;
assert (list.size() == fields.size());
return list;
}
// /////////////////////////////
// SettableStructObjectInspector
@Override
public Object create() {
ArrayList<Object> a = new ArrayList<>(fields.size());
for (int i = 0; i < fields.size(); i++) {
a.add(null);
}
return a;
}
@Override
public Object setStructFieldData(Object struct, StructField field,
Object fieldValue) {
ArrayList<Object> a = (ArrayList<Object>) struct;
MyField myField = (MyField) field;
a.set(myField.fieldID, fieldValue);
return a;
}
}