public class RandomRowSplittable extends java.lang.Object implements RowSplittable
Constructor and Description |
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RandomRowSplittable(StarTable table)
Constructs a splittable for a given table.
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Modifier and Type | Method and Description |
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void |
close()
Indicates that this sequence will not be required any more.
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java.lang.Object |
getCell(int icol)
Returns the contents of a cell in the current row.
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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.
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boolean |
next()
Attempts to advance the current row to the next one.
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java.util.function.LongSupplier |
rowIndex()
Returns a supplier for the index of the row currently being processed,
if possible.
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RandomRowSplittable |
split()
Attempts to partition this object into two halves,
ideally of similar size.
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long |
splittableSize()
Provides an estimate of the number of processable items in this object.
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public RandomRowSplittable(StarTable table) throws java.io.IOException
table
- random-access tablejava.lang.UnsupportedOperationException
- if table is not random-accessjava.io.IOException
public long splittableSize()
Splittable
If no estimate for the size is available, a negative value should be returned.
splittableSize
in interface Splittable<RowSplittable>
public RandomRowSplittable split()
Splittable
Following a successful call, the two parts may be processed in different threads.
split
in interface Splittable<RowSplittable>
Spliterator.trySplit()
public java.util.function.LongSupplier rowIndex()
RowSplittable
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.
rowIndex
in interface RowSplittable
public boolean next() throws java.io.IOException
RowSequence
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.next
in interface RowSequence
next
in interface Sequence
true
iff this sequence has been advanced to the
next rowjava.io.IOException
- if there is some errorpublic java.lang.Object getCell(int icol) throws java.io.IOException
RowSequence
getColumnInfo(icol).getContentClass()
.
An unchecked exception will be thrown if there is no current
row (next
has not yet been called).getCell
in interface RowData
getCell
in interface RowSequence
icol
- column indexicol
in the current rowjava.io.IOException
- if there is an error reading the datapublic java.lang.Object[] getRow() throws java.io.IOException
RowSequence
next
has not yet been called).getRow
in interface RowData
getRow
in interface RowSequence
irow
java.io.IOException
- if there is an error reading the datapublic void close() throws java.io.IOException
RowSequence
close
is undefined.close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in interface RowSequence
java.io.IOException