org.apache.hawq.pxf.plugins.hbase

Class HBaseFilterBuilder

java.lang.Object

org.apache.hawq.pxf.plugins.hbase.HBaseFilterBuilder

All Implemented Interfaces:

FilterParser.FilterBuilder

public class HBaseFilterBuilder
extends java.lang.Object
implements FilterParser.FilterBuilder

This is the implementation of FilterParser.FilterBuilder for HBase.

The class uses the filter parser code to build a filter object, either simple (single Filter class) or a compound (FilterList) for HBaseAccessor to use for its scan.

This is done before the scan starts. It is not a scan time operation.

HBase row key column is a special case. If the user defined row key column as TEXT and used <,>,<=,>=,= operators the startkey (>/>=) and the endkey (</<=) are stored in addition to the created filter. This is an addition on top of regular filters and does not replace any logic in HBase filter objects.

Constructor Summary

Constructors

Constructor and Description
HBaseFilterBuilder(HBaseTupleDescription tupleDescription)

Method Summary

Modifier and Type	Method and Description
java.lang.Object	build(FilterParser.Operation opId, java.lang.Object leftOperand, java.lang.Object rightOperand) Builds a filter from the input operands and operation.
byte[]	endKey() Returns the endKey for scanning the HBase table.
org.apache.hadoop.hbase.filter.Filter	getFilterObject(java.lang.String filterString) Translates a filterString into a HBase Filter object.
byte[]	startKey() Returns the startKey for scanning the HBase table.

Methods inherited from class java.lang.Object

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

Constructor Detail

HBaseFilterBuilder

public HBaseFilterBuilder(HBaseTupleDescription tupleDescription)

Method Detail

getFilterObject

public org.apache.hadoop.hbase.filter.Filter getFilterObject(java.lang.String filterString)
                                                      throws java.lang.Exception

Translates a filterString into a HBase Filter object.

Parameters:

filterString - filter string

Returns:

filter object

Throws:

java.lang.Exception - if parsing failed

startKey

public byte[] startKey()

Returns the startKey for scanning the HBase table. If the user specified a > / >= operation on a textual row key column, this value will be returned. Otherwise, the start of table.

Returns:

start key for scanning HBase table

endKey

public byte[] endKey()

Returns the endKey for scanning the HBase table. If the user specified a < / <= operation on a textual row key column, this value will be returned. Otherwise, the end of table.

Returns:

end key for scanning HBase table

build

public java.lang.Object build(FilterParser.Operation opId,
                              java.lang.Object leftOperand,
                              java.lang.Object rightOperand)
                       throws java.lang.Exception

Builds a filter from the input operands and operation. Two kinds of operations are handled:

1. Simple operation between FilterParser.Constant and FilterParser.ColumnIndex. Supported operations are <, >, <=, <=, >=, =, !=.
2. Compound operations between Filter objects. The only supported operation is AND.

This function is called by FilterParser, each time the parser comes across an operator.

Specified by:

build in interface FilterParser.FilterBuilder

Parameters:

opId - the parse operation to perform

leftOperand - the left operand

rightOperand - the right operand

Returns:

the built filter

Throws:

java.lang.Exception - if building the filter failed