org.apache.hadoop.hive.serde2.lazy

Class LazyMap

java.lang.Object

org.apache.hadoop.hive.serde2.lazy.LazyObject<OI>

org.apache.hadoop.hive.serde2.lazy.LazyNonPrimitive<LazyMapObjectInspector>

org.apache.hadoop.hive.serde2.lazy.LazyMap

All Implemented Interfaces:

LazyObjectBase

Direct Known Subclasses:

LazyAccumuloMap, LazyHBaseCellMap

public class LazyMap
extends LazyNonPrimitive<LazyMapObjectInspector>

LazyMap stores a map of Primitive LazyObjects to LazyObjects. Note that the keys of the map cannot contain null. LazyMap does not deal with the case of a NULL map. That is handled by the parent LazyObject.

Field Summary

Fields

Modifier and Type	Field and Description
protected LinkedHashMap<Object,Object>	cachedMap cachedMap is reused for different calls to getMap().
static org.apache.commons.logging.Log	LOG

Fields inherited from class org.apache.hadoop.hive.serde2.lazy.LazyNonPrimitive

bytes, length, start

Fields inherited from class org.apache.hadoop.hive.serde2.lazy.LazyObject

isNull, oi

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	LazyMap(LazyMapObjectInspector oi) Construct a LazyMap object with the ObjectInspector.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	enlargeArrays() Enlarge the size of arrays storing information for the elements inside the array.
Map<Object,Object>	getMap() Return the map object representing this LazyMap.
int	getMapSize() Get the size of the map represented by this LazyMap.
Object	getMapValueElement(Object key) Get the value in the map for the key.
protected boolean	getParsed()
void	init(ByteArrayRef bytes, int start, int length) Set the row data for this LazyArray.
protected void	setParsed(boolean parsed)

Methods inherited from class org.apache.hadoop.hive.serde2.lazy.LazyNonPrimitive

hashCode, isNull, isNull

Methods inherited from class org.apache.hadoop.hive.serde2.lazy.LazyObject

getInspector, getObject, setInspector, setNull

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

cachedMap

protected LinkedHashMap<Object,Object> cachedMap

cachedMap is reused for different calls to getMap(). But each LazyMap has a separate cachedMap so we won't overwrite the data by accident.

Constructor Detail

LazyMap

protected LazyMap(LazyMapObjectInspector oi)

Construct a LazyMap object with the ObjectInspector.

Method Detail

init

public void init(ByteArrayRef bytes,
        int start,
        int length)

Set the row data for this LazyArray.

Specified by:

init in interface LazyObjectBase

Overrides:

init in class LazyNonPrimitive<LazyMapObjectInspector>

Parameters:

bytes - The wrapper of the byte[].

start - The start position inside the bytes.

length - The length of the data, starting from "start"

See Also:

LazyObject.init(ByteArrayRef, int, int)

enlargeArrays

protected void enlargeArrays()

Enlarge the size of arrays storing information for the elements inside the array.

getMapValueElement

public Object getMapValueElement(Object key)

Get the value in the map for the key. If there are multiple matches (which is possible in the serialized format), only the first one is returned. The most efficient way to get the value for the key is to serialize the key and then try to find it in the array. We do linear search because in most cases, user only wants to get one or two values out of the map, and the cost of building up a HashMap is substantially higher.

Parameters:

key - The key object that we are looking for.

Returns:

The corresponding value object, or NULL if not found

getMap

public Map<Object,Object> getMap()

Return the map object representing this LazyMap. Note that the keyObjects will be Writable primitive objects.

Returns:

the map object

getMapSize

public int getMapSize()

Get the size of the map represented by this LazyMap.

Returns:

The size of the map, -1 for NULL map.

getParsed

protected boolean getParsed()

setParsed

protected void setParsed(boolean parsed)