Package uk.ac.starlink.table
Class RandomRowSequence
- java.lang.Object
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- uk.ac.starlink.table.RandomRowSequence
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- All Implemented Interfaces:
RowSequence
public class RandomRowSequence extends java.lang.Object implements RowSequence
An implementation of RowSequence which obtains its data from a random-access StarTable object.
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Constructor Summary
Constructors Constructor Description RandomRowSequence(StarTable startab)
Constructs a RowSequence from a StarTable which must offer random access and know its number of rows.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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 advances the current row to the next one.
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Constructor Detail
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RandomRowSequence
public RandomRowSequence(StarTable startab)
Constructs a RowSequence from a StarTable which must offer random access and know its number of rows.- Parameters:
startab
- the StarTable object providing the data- Throws:
java.lang.IllegalArgumentException
- if startab.isRandom()==false or startab.getRowCount()<0
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Method Detail
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next
public boolean next()
Description copied from interface:RowSequence
Attempts to advances 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
- Returns:
- true iff this sequence has been advanced to the next row
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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 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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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 interfaceRowSequence
- 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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close
public void close()
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 interfaceRowSequence
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