org.apache.hadoop.zebra.types

Class Projection

java.lang.Object

org.apache.hadoop.zebra.types.Projection

public class Projection
extends Object

Projection for Table and Column Group

Field Summary

Fields

Modifier and Type	Field and Description
static String	source_table_vcolumn_name

Constructor Summary

Constructors

Constructor and Description
Projection(Schema s) ctor for full projection
Projection(Schema s, String projection) ctor for partial projection

Method Summary

Methods

Modifier and Type	Method and Description
static int	getColumnIndex(String projection, String colname) Get a column's index in a projection.
Schema.ColumnSchema	getColumnSchema(int i) Get a particular projected column's schema
int	getNumColumns() Get number of columns in the projection
static int	getNumColumns(String projection) Get number of columns from a projection string
Schema	getProjectionSchema()
static String	getProjectionStr(String[] names) Get a projection string from a series of column names
Schema	getSchema() accessor to the projected schema including invalid columns
static Integer[]	getVirtualColumnIndices(String projection) Get the indices of all virtual columns
static boolean	isVirtualColumn(String name) if a column name is on a virtual column
static Schema	toSchema(String projection) Get schema from a projection string: all map keys are lost
String	toString() Get the string representation

Methods inherited from class java.lang.Object

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

Field Detail

source_table_vcolumn_name

public static final String source_table_vcolumn_name

See Also:

Constant Field Values

Constructor Detail

Projection

public Projection(Schema s)

ctor for full projection

Projection

public Projection(Schema s,
          String projection)
           throws ParseException

ctor for partial projection

Throws:

ParseException

Method Detail

isVirtualColumn

public static boolean isVirtualColumn(String name)

if a column name is on a virtual column

getVirtualColumnIndices

public static Integer[] getVirtualColumnIndices(String projection)

Get the indices of all virtual columns

getSchema

public Schema getSchema()

accessor to the projected schema including invalid columns

getProjectionSchema

public Schema getProjectionSchema()

getColumnSchema

public Schema.ColumnSchema getColumnSchema(int i)

Get a particular projected column's schema

toString

public String toString()

Get the string representation

Overrides:

toString in class Object

getNumColumns

public int getNumColumns()

Get number of columns in the projection

getNumColumns

public static int getNumColumns(String projection)

Get number of columns from a projection string

getProjectionStr

public static String getProjectionStr(String[] names)

Get a projection string from a series of column names

toSchema

public static Schema toSchema(String projection)
                       throws ParseException

Get schema from a projection string: all map keys are lost

Throws:

ParseException

getColumnIndex

public static int getColumnIndex(String projection,
                 String colname)

Get a column's index in a projection.

Parameters:

projection -

colname -

Returns:

-1 if the column is not found in projection