RandomRowSplittable (STIL)

java.lang.Object
- uk.ac.starlink.table.RandomRowSplittable

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, RowData, RowSequence, RowSplittable, Sequence, Splittable<RowSplittable>
```
public class RandomRowSplittable
extends java.lang.Object
implements RowSplittable
```
RowSplittable based on a RowAccess.

Since:

4 Aug 2020

Constructor Summary

Constructors
Constructor and Description

RandomRowSplittable(StarTable table)
Constructs a splittable for a given table.

Constructors
Constructor and Description
`RandomRowSplittable(StarTable table)` Constructs a splittable for a given table.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Indicates that this sequence will not be required any more.
`java.lang.Object`	`getCell(int icol)` Returns the contents of a cell in the current row.
`java.lang.Object[]`	`getRow()` Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table.
`boolean`	`next()` Attempts to advance the current row to the next one.
`java.util.function.LongSupplier`	`rowIndex()` Returns a supplier for the index of the row currently being processed, if possible.
`RandomRowSplittable`	`split()` Attempts to partition this object into two halves, ideally of similar size.
`long`	`splittableSize()` Provides an estimate of the number of processable items in this object.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - RandomRowSplittable
```
public RandomRowSplittable(StarTable table)
                    throws java.io.IOException
```
    Constructs a splittable for a given table.
    
    Parameters:
    
    table - random-access table
    
    Throws:
    
    java.lang.UnsupportedOperationException - if table is not random-access
    
    java.io.IOException
- Method Detail
  - splittableSize
```
public long splittableSize()
```
    Description copied from interface: Splittable
    
    Provides an estimate of the number of processable items in this object. A processable item is not a well-defined quantity, but it should generally be something that can be processed fast. For instance, if this object represents a collection of collections, the value that should be returned is the total number of elements rather than the number of collections.
    If no estimate for the size is available, a negative value should be returned.
    
    Specified by:
    
    splittableSize in interface Splittable<RowSplittable>
    
    Returns:
    
    approximate size, or negative value if not known
  - split
```
public RandomRowSplittable split()
```
    Description copied from interface: Splittable
    
    Attempts to partition this object into two halves, ideally of similar size. If a non-null value is returned, then the content previously contained by this object is now split between this object and the returned object. If for any reason a split is not carried out, null is returned.
    Following a successful call, the two parts may be processed in different threads.
    
    Specified by:
    
    split in interface Splittable<RowSplittable>
    
    Returns:
    
    other half of this splittable, or null
    
    See Also:
    
    Spliterator.trySplit()
  - rowIndex
```
public java.util.function.LongSupplier rowIndex()
```
    Description copied from interface: RowSplittable
    
    Returns a supplier for the index of the row currently being processed, if possible. The row index is a global value; when accessing the first row of a top-level RowSplittable, the value returned by this supplier should be the first index in the table. But for objects resulting from splitting a top-level instance into sub-instances, the return value should reflect the index in the original sequence of rows; each index should be returned from only one of the splittables resulting from splitting a top-level instance.
    Typically, the row index will start at 0 and increment for each row, but the numbering may be different depending on the requirements of the implementation or usage.
    Before the RowSequence.next() method has been called, the return value will be one less than the first row index. After RowSequence.next has returned false, the value is undefined.
    Depending on the implementation, it may not be possible to determine the row index (for instance if the sequence is split into sub-splittables of unknown size). In such cases, this method returns null. The null-ness of the return value must be the same for all instances of the splittable hierarchy for a given sequence, so don't return a non-null value for the first splittable and then null values for some or all of its children.
    
    Specified by:
    
    rowIndex in interface RowSplittable
    
    Returns:
    
    supplier for the globally-referenced row index value of the current row of this sequence, or null
  - next
```
public boolean next()
             throws java.io.IOException
```
    Description copied from interface: RowSequence
    
    Attempts to advance the current row to the next one. If true is returned the attempt has been successful, and if false is returned there are no more rows in this sequence. Since the initial position of a RowSequence is before the first row, this method must be called before current row data can be accessed using the RowSequence.getCell(int) or RowSequence.getRow() methods.
    
    Specified by:
    
    next in interface RowSequence
    
    Specified by:
    
    next in interface Sequence
    
    Returns:
    
    true iff this sequence has been advanced to the next row
    
    Throws:
    
    java.io.IOException - if there is some error
  - getCell
```
public java.lang.Object getCell(int icol)
                         throws java.io.IOException
```
    Description copied from interface: RowSequence
    
    Returns the contents of a cell in the current row. The class of the returned object should be the same as, or a subclass of, the class returned by getColumnInfo(icol).getContentClass(). An unchecked exception will be thrown if there is no current row (next has not yet been called).
    
    Specified by:
    
    getCell in interface RowData
    
    Specified by:
    
    getCell in interface RowSequence
    
    Parameters:
    
    icol - column index
    
    Returns:
    
    the contents of cell icol in the current row
    
    Throws:
    
    java.io.IOException - if there is an error reading the data
  - getRow
```
public java.lang.Object[] getRow()
                          throws java.io.IOException
```
    Description copied from interface: RowSequence
    
    Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table. An unchecked exception will be thrown if there is no current row (next has not yet been called).
    
    Specified by:
    
    getRow in interface RowData
    
    Specified by:
    
    getRow in interface RowSequence
    
    Returns:
    
    an array of the objects in each cell in row irow
    
    Throws:
    
    java.io.IOException - if there is an error reading the data
  - close
```
public void close()
           throws java.io.IOException
```
    Description copied from interface: RowSequence
    
    Indicates that this sequence will not be required any more. This should release resources associated with this object. The effect of calling any of the other methods following a close is undefined.
    
    Specified by:
    
    close in interface java.io.Closeable
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
    
    Specified by:
    
    close in interface RowSequence
    
    Throws:
    
    java.io.IOException

Class RandomRowSplittable

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

RandomRowSplittable

Method Detail

splittableSize

split

rowIndex

next

getCell

getRow

close