Package uk.ac.starlink.table
Class AccessRowSequence
- java.lang.Object
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- uk.ac.starlink.table.AccessRowSequence
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
,RowData
,RowSequence
,uk.ac.starlink.util.Sequence
public class AccessRowSequence extends java.lang.Object implements RowSequence
RowSequence implementation based on a RowAccess.- Since:
- 24 Jul 2020
- Author:
- Mark Taylor
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Constructor Summary
Constructors Constructor Description AccessRowSequence(RowAccess racc, long nrow)
Constructor.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Indicates that this sequence will not be required any more.static AccessRowSequence
createInstance(StarTable table)
Constructs an AccessRowSequence based on a given table.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.
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Constructor Detail
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AccessRowSequence
public AccessRowSequence(RowAccess racc, long nrow)
Constructor.- Parameters:
racc
- row access providing data accessnrow
- number of rows
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Method Detail
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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 theRowSequence.getCell(int)
orRowSequence.getRow()
methods.- Specified by:
next
in interfaceRowSequence
- Specified by:
next
in interfaceuk.ac.starlink.util.Sequence
- Returns:
- true iff this sequence has been advanced to the next row
- Throws:
java.io.IOException
- if there is some error
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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 interfaceRowData
- Specified by:
getCell
in interfaceRowSequence
- 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
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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 interfaceRowData
- Specified by:
getRow
in interfaceRowSequence
- Returns:
- an array of the objects in each cell in row irow
- Throws:
java.io.IOException
- if there is an error reading the data
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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 aclose
is undefined.- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Specified by:
close
in interfaceRowSequence
- Throws:
java.io.IOException
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createInstance
public static AccessRowSequence createInstance(StarTable table) throws java.io.IOException
Constructs an AccessRowSequence based on a given table.- Parameters:
table
- table- Returns:
- new row access
- Throws:
java.io.IOException
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