WrapperStarTable (Starlink-UK API)

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

All Implemented Interfaces:

Closeable, AutoCloseable, StarTable

Direct Known Subclasses:

AddColumnsTable, ColumnPermutedStarTable, ColumnStoreStarTable, ConcatStarTable, EmptyStarTable, EveryTable, ExplodedStarTable, HeadTable, JELSelectorTable, JELTable, MetaCopyStarTable, ProgressBarStarTable, ProgressLineStarTable, RepeatTable, ReplaceValueTable, RowPermutedStarTable, RowSubsetStarTable, SelectorStarTable, SeqConcatStarTable, TailTable
```
public class WrapperStarTable
extends Object
implements StarTable
```
StarTable which wraps another StarTable. This class acts as a wrapper around an existing 'base' StarTable object; almost all its methods are implemented by forwarding to the corresponding methods of that base table. The exception is the getURL() method which returns null as an indication that the actual table is not a persistent one (though it may be based on, and even identical to, a persistent one).
This class is provided so that it can be extended by subclasses which modify the view of the base table in useful ways.
Subclasses should take care to ensure that all the data access methods are overridden in a consistent way: getCell(long, int), getRow(long), getRowSequence(), getRowAccess() and getRowSplittable().

Author:

Mark Taylor (Starlink)

See Also:

WrapperRowSequence

Field Summary

Fields
Modifier and Type Field and Description

protected StarTable baseTable

Fields
Modifier and Type	Field and Description
`protected StarTable`	`baseTable`

Constructor Summary

Constructors
Constructor and Description

WrapperStarTable(StarTable baseTable)
Constructs a new WrapperStarTable from a given base table.

Constructors
Constructor and Description
`WrapperStarTable(StarTable baseTable)` Constructs a new `WrapperStarTable` from a given base table.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static int`	`checkedLongToInt(long lval)` Convenience method to get an `int` value from a `long`.
`void`	`close()` Relinquishes any resources associated with this table.
`StarTable`	`getBaseTable()` Returns the base table underlying this wrapper table.
`Object`	`getCell(long irow, int icol)` Returns the contents of a given table cell.
`List<ValueInfo>`	`getColumnAuxDataInfos()` Returns an ordered list of ValueInfo objects representing the auxiliary metadata returned by `getColumnInfo(int).getAuxData()` calls.
`int`	`getColumnCount()` Returns the number of columns in this table.
`ColumnInfo`	`getColumnInfo(int icol)` Returns the object describing the data in a given column.
`String`	`getName()` Returns the name of this table, if it has one.
`DescribedValue`	`getParameterByName(String parname)` Returns a parameter (table-wide metadata item) of this table located by its name.
`List<DescribedValue>`	`getParameters()` Returns a list of table parameters, that is metadata items which pertain to the entire table.
`Object[]`	`getRow(long irow)` Returns the contents of a given table row.
`RowAccess`	`getRowAccess()` Returns an object which can provide random access to this table's data, if random access is implemented.
`long`	`getRowCount()` Returns the number of rows in this table, if known.
`RowSequence`	`getRowSequence()` Returns an object which can iterate over all the rows in the table sequentially.
`RowSplittable`	`getRowSplittable()` Returns an object which can iterate over all the rows in the table, but which may also be requested to split recursively for potentially parallel processing.
`URL`	`getURL()` Initially returns `null` to indicate that this table itself is not persistent.
`boolean`	`isRandom()` Indicates whether random access is provided by this table.
`void`	`setName(String name)` Sets the name of this table.
`void`	`setParameter(DescribedValue dval)` Adds the given DescribedValue to the list of parameter metadata objects associated with this table.
`void`	`setURL(URL url)` Sets the URL of this table.
`String`	`toString()` Returns an indication of the wrapper structure of this table.

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

- Field Detail
  - baseTable
```
protected StarTable baseTable
```
- Constructor Detail
  - WrapperStarTable
```
public WrapperStarTable(StarTable baseTable)
```
    Constructs a new WrapperStarTable from a given base table.
    
    Parameters:
    
    baseTable - the table to which methods invoked upon the new wrapper table will be forwarded
- Method Detail
  - getBaseTable
```
public StarTable getBaseTable()
```
    Returns the base table underlying this wrapper table.
    
    Returns:
    
    the table to which methods invoked upon this wrappter table are forwarded
  - getColumnCount
```
public int getColumnCount()
```
    Description copied from interface: StarTable
    
    Returns the number of columns in this table.
    
    Specified by:
    
    getColumnCount in interface StarTable
    
    Returns:
    
    the number of columns
  - getRowCount
```
public long getRowCount()
```
    Description copied from interface: StarTable
    
    Returns the number of rows in this table, if known. If the number of rows cannot be (easily) determined, a value of -1 will be returned.
    
    Specified by:
    
    getRowCount in interface StarTable
    
    Returns:
    
    the number of rows, or -1
  - getURL
```
public URL getURL()
```
    Initially returns null to indicate that this table itself is not persistent.
    
    Specified by:
    
    getURL in interface StarTable
    
    Returns:
    
    the URL of this table, or null if none is known
  - setURL
```
public void setURL(URL url)
```
    Description copied from interface: StarTable
    
    Sets the URL of this table. It ought to be possible in principle to reconstruct this table by reading the resource at url. If called, the supplied url should provide the return value for subsequent calls of StarTable.getURL().
    
    Specified by:
    
    setURL in interface StarTable
    
    Parameters:
    
    url - table URL
  - getName
```
public String getName()
```
    Description copied from interface: StarTable
    
    Returns the name of this table, if it has one. The meaning of the name is not defined, but it will typically be a short string of text indicating the identity of this table.
    
    Specified by:
    
    getName in interface StarTable
    
    Returns:
    
    a name for this table, or null if no suitable one exists
  - setName
```
public void setName(String name)
```
    Description copied from interface: StarTable
    
    Sets the name of this table. If called, the supplied name should provide the return value for subsequent calls of StarTable.getName().
    
    Specified by:
    
    setName in interface StarTable
    
    Parameters:
    
    name - table name
  - getParameters
```
public List<DescribedValue> getParameters()
```
    Description copied from interface: StarTable
    
    Returns a list of table parameters, that is metadata items which pertain to the entire table.
    
    Specified by:
    
    getParameters in interface StarTable
    
    Returns:
    
    a List of DescribedValue objects constituting table-wide metadata not covered elsewhere in this interface
  - getParameterByName
```
public DescribedValue getParameterByName(String parname)
```
    Description copied from interface: StarTable
    
    Returns a parameter (table-wide metadata item) of this table located by its name. If more than one parameter with the given name exists, an arbitrary one will be returned. If no parameter with the given name exists, null will be returned.
    
    Specified by:
    
    getParameterByName in interface StarTable
    
    Parameters:
    
    parname - the name of the table parameter required
  - setParameter
```
public void setParameter(DescribedValue dval)
```
    Description copied from interface: StarTable
    
    Adds the given DescribedValue to the list of parameter metadata objects associated with this table. If an item in the parameter list with the same name as the supplied value already exists, it is removed from the list.
    
    Specified by:
    
    setParameter in interface StarTable
    
    Parameters:
    
    dval - the new parameter datum to add
  - getColumnInfo
```
public ColumnInfo getColumnInfo(int icol)
```
    Description copied from interface: StarTable
    
    Returns the object describing the data in a given column.
    
    Specified by:
    
    getColumnInfo in interface StarTable
    
    Parameters:
    
    icol - the column for which header information is required
    
    Returns:
    
    a ValueInfo object for column icol
  - getColumnAuxDataInfos
```
public List<ValueInfo> getColumnAuxDataInfos()
```
    Description copied from interface: StarTable
    
    Returns an ordered list of ValueInfo objects representing the auxiliary metadata returned by getColumnInfo(int).getAuxData() calls. The idea is that the resulting list can be used to find out the kind of per-column metadata which can be expected to be found in some or all columns of this table. Each item in the returned list should have a unique name, and other characteristics which are applicable to auxData items which may be returned from any of the columns in this table.
    The order of the list may indicate some sort of natural ordering of these keys. The returned list is not guaranteed to be complete; it is legal to return an empty list if nothing is known about auxiliary metadata. The list ought not to contain duplicate elements.
    
    Specified by:
    
    getColumnAuxDataInfos in interface StarTable
    
    Returns:
    
    an unmodifiable ordered set of known metadata keys
    
    See Also:
    
    DefaultValueInfo.getAuxData()
  - getRowSequence
```
public RowSequence getRowSequence()
                           throws IOException
```
    Description copied from interface: StarTable
    
    Returns an object which can iterate over all the rows in the table sequentially. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.
    
    Specified by:
    
    getRowSequence in interface StarTable
    
    Returns:
    
    new RowSequence
    
    Throws:
    
    IOException - if there is an error providing access
  - getRowAccess
```
public RowAccess getRowAccess()
                       throws IOException
```
    Description copied from interface: StarTable
    
    Returns an object which can provide random access to this table's data, if random access is implemented. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.
    
    Specified by:
    
    getRowAccess in interface StarTable
    
    Returns:
    
    new RowAccess
    
    Throws:
    
    IOException - if there is an error setting up access
  - getRowSplittable
```
public RowSplittable getRowSplittable()
                               throws IOException
```
    Description copied from interface: StarTable
    
    Returns an object which can iterate over all the rows in the table, but which may also be requested to split recursively for potentially parallel processing.
    The return value must be non-null, and may provide splitting arrangements specially appropriate for the implementation. If this table 'wraps' an upstream table, it is usually best to base the implementation on calls to the the upstream getRowSplittable method, so that upstream policy about how to divide up the table is respected. However, implementations without special requirements may return Tables.getDefaultRowSplittable(this).
    
    Specified by:
    
    getRowSplittable in interface StarTable
    
    Returns:
    
    new RowSplittable
    
    Throws:
    
    IOException
    
    See Also:
    
    RowRunner
  - isRandom
```
public boolean isRandom()
```
    Description copied from interface: StarTable
    
    Indicates whether random access is provided by this table. Only if the result is true may the StarTable.getRowAccess(), StarTable.getRow(long) and StarTable.getCell(long, int) methods be used.
    
    Specified by:
    
    isRandom in interface StarTable
    
    Returns:
    
    true if table random access methods are available
  - getCell
```
public Object getCell(long irow,
                      int icol)
               throws IOException
```
    Description copied from interface: StarTable
    
    Returns the contents of a given table cell. The class of the returned object should be the same as, or a subclass of, the class returned by getColumnInfo(icol).getContentClass().
    This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.
    
    Specified by:
    
    getCell in interface StarTable
    
    Parameters:
    
    irow - the index of the cell's row
    
    icol - the index of the cell's column
    
    Returns:
    
    the contents of this cell
    
    Throws:
    
    IOException - if there is an error reading the data
  - getRow
```
public Object[] getRow(long irow)
                throws IOException
```
    Description copied from interface: StarTable
    
    Returns the contents of a given table row. The returned value is equivalent to an array formed of all the objects returned by getCell(irow,icol) for all the columns icol in sequence.
    This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.
    
    Specified by:
    
    getRow in interface StarTable
    
    Parameters:
    
    irow - the index of the row to retrieve
    
    Returns:
    
    an array of the objects in each cell in row irow
    
    Throws:
    
    IOException - if there is an error reading the data
  - close
```
public void close()
           throws IOException
```
    Description copied from interface: StarTable
    
    Relinquishes any resources associated with this table. This may do nothing, and calling it is often not required, but it provides an opportunity to force release of file descriptors or other resources that are not well handled by garbage collection if the table itself holds them. It is not intended for release of heap-based resources, for which garbage collection already provides adequate management.
    Following a call to this method, any attempt to use this table or objects such as RowSequences obtained from it will result in undefined behaviour.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface StarTable
    
    Throws:
    
    IOException
  - checkedLongToInt
```
public static int checkedLongToInt(long lval)
```
    Convenience method to get an int value from a long. Invokes Tables.checkedLongToInt(long).
  - toString
```
public String toString()
```
    Returns an indication of the wrapper structure of this table.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    string representation

Class WrapperStarTable

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

baseTable

Constructor Detail

WrapperStarTable

Method Detail

getBaseTable

getColumnCount

getRowCount

getURL

setURL

getName

setName

getParameters

getParameterByName

setParameter

getColumnInfo

getColumnAuxDataInfos

getRowSequence

getRowAccess

getRowSplittable

isRandom

getCell

getRow

close

checkedLongToInt

toString