Package uk.ac.starlink.table
Class ReaderRowSequence
- java.lang.Object
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- uk.ac.starlink.table.ReaderRowSequence
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- All Implemented Interfaces:
RowSequence
public abstract class ReaderRowSequence extends java.lang.Object implements RowSequence
Partial implementation of RowSequence suitable for subclassing by classes which can read a row at a time and don't know when the row stream will come to an end. Concrete subclasses have to implement thereadRow()
method. They may also want to overrideclose()
.- Author:
- Mark Taylor (Starlink)
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Constructor Summary
Constructors Constructor Description ReaderRowSequence()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
close()
The ReaderRowSequence implementation does nothing.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.protected abstract java.lang.Object[]
readRow()
Acquires the next row of objects from the input stream.
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Method Detail
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readRow
protected abstract java.lang.Object[] readRow() throws java.io.IOException
Acquires the next row of objects from the input stream. When there are no more rows to read this method must return null; note it should not throw an exception to indicate this fact. Otherwise it must return an array of objects representing the row content for the next row.- Returns:
- the next row, or null if there are no more
- Throws:
java.io.IOException
- if there is trouble reading the data
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next
public boolean next() throws java.io.IOException
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
- Throws:
java.io.IOException
- if there is some error
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getCell
public java.lang.Object getCell(int icol)
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
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getRow
public java.lang.Object[] getRow()
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
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close
public void close() throws java.io.IOException
The ReaderRowSequence implementation does nothing.- Specified by:
close
in interfaceRowSequence
- Throws:
java.io.IOException
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