uk.ac.starlink.table

Class PrimitiveArrayColumn

java.lang.Object

uk.ac.starlink.table.ColumnData

uk.ac.starlink.table.ArrayColumn

uk.ac.starlink.table.PrimitiveArrayColumn

public abstract class PrimitiveArrayColumn
extends ArrayColumn

A column which provides data storage in a java array of primitives. Thus a float[] array is used rather than a Float[] array, which should be more efficient on memory. Null values may be stored in the column; a BitSet is used to keep track of which elements are null. By default (on column construction), none of the values are null.

Obtain an instance of this class using one of the makePrimitiveColumn methods.

Author:

Mark Taylor (Starlink)

Method Summary

Modifier and Type	Method and Description
static PrimitiveArrayColumn	makePrimitiveColumn(ColumnInfo base, long rowCount) Obtains an ArrayColumn object based on a template object with a given number of rows.
static PrimitiveArrayColumn	makePrimitiveColumn(ColumnInfo base, Object data) Constructs a new PrimitiveArrayColumn based on a given data array.
protected Object	readValue(int irow)
void	setAllNulls() Sets all the elements in this column to null.
void	setNoNulls() Sets all the elements in this column to non-null values.
protected void	storeValue(int irow, Object val)

Methods inherited from class uk.ac.starlink.table.ArrayColumn

getArray, isWritable, makeColumn, makeColumn, makeColumn, readValue, storeValue

Methods inherited from class uk.ac.starlink.table.ColumnData

getColumnInfo, setColumnInfo

Methods inherited from class java.lang.Object

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

Method Detail

storeValue

protected void storeValue(int irow,
                          Object val)

readValue

protected Object readValue(int irow)

setAllNulls

public void setAllNulls()

Sets all the elements in this column to null. Each will remain null until it is explicitly set (to a non-null value) using storeValue(int, java.lang.Object) or until setNoNulls() is called.

setNoNulls

public void setNoNulls()

Sets all the elements in this column to non-null values. The value of each cell will be determined by the value of the underlying data array, until it is set using storeValue(int, java.lang.Object) with a null argument, or setAllNulls() is called.

makePrimitiveColumn

public static PrimitiveArrayColumn makePrimitiveColumn(ColumnInfo base,
                                                       Object data)

Constructs a new PrimitiveArrayColumn based on a given data array. The contentClass of the given base column info must be compatible with the supplied data array; it should be that of the corresponding wrapper class. Alternatively, the base column info may have a null content class, in which case the column info for the new column will be set appropriately from the data array.

Parameters:

base - the column info on which to base this column's info

data - an array of primitives which will form the storage for this column

Returns:

a new PrimitiveArrayColumn based on base backed by data

Throws:

IllegalArgumentException - if data isn't an array or base.getContentClass() is incompatible with data

makePrimitiveColumn

public static PrimitiveArrayColumn makePrimitiveColumn(ColumnInfo base,
                                                       long rowCount)

Obtains an ArrayColumn object based on a template object with a given number of rows. A new ColumnInfo object will be constructed based on the given one.

Parameters:

base - the template ColumnInfo - note this is not the actual ColumnInfo object which will be returned by the getColumnInfo method of the returned ArrayColumn

rowCount - the number of rows it is to hold

Returns:

a new PrimitiveArrayColumn based on base with storage for rowCount elements