ParallelResultRowSequence (Starjava TTOOLS API)

java.lang.Object
- uk.ac.starlink.ttools.cone.ParallelResultRowSequence

All Implemented Interfaces:

uk.ac.starlink.table.RowSequence, ConeQueryRowSequence, ConeResultRowSequence
```
public class ParallelResultRowSequence
extends java.lang.Object
implements ConeResultRowSequence
```
ConeResultRowSequence implementation which uses a fixed number of worker threads to dispatch cone queries in parallel. The result table has the same ordering as if they had been done in sequence.

Since:

18 Jan 2008

Author:

Mark Taylor

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`DEFAULT_MAXPAR`	Default maximum value for the number of threads that should be permitted for a query.
`static java.lang.String`	`MAXPAR_PROP`	Name of system property "service.maxparallel" which may be used to adjust the maximum parallelism.

Constructor Summary

Constructors
Constructor	Description
`ParallelResultRowSequence(ConeQueryRowSequence querySeq, ConeSearcher coneSearcher, ConeErrorPolicy errAct, Coverage coverage, boolean bestOnly, boolean distFilter, java.lang.String distanceCol, int parallelism)`	Constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`
`java.lang.Object`	`getCell(int icol)`
`uk.ac.starlink.table.StarTable`	`getConeResult()`	Returns the result of the cone search for the current row of this sequence.
`double`	`getDec()`	Get central declination for the current row's cone search request in degrees.
`long`	`getIndex()`	Get the index in the underlying table to which the current row relates.
`static int`	`getMaxParallelism()`	Returns the maximum parallelism value which should permitted in this JVM.
`double`	`getRa()`	Get central right ascension for the current row's cone search request in degrees.
`double`	`getRadius()`	Get search radius for the current row's cone search request in degrees.
`java.lang.Object[]`	`getRow()`
`boolean`	`next()`

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

- Field Detail
  - DEFAULT_MAXPAR
```
public static final int DEFAULT_MAXPAR
```
    Default maximum value for the number of threads that should be permitted for a query.
    
    See Also:
    
    MAXPAR_PROP, getMaxParallelism(), Constant Field Values
  - MAXPAR_PROP
```
public static final java.lang.String MAXPAR_PROP
```
    Name of system property "service.maxparallel" which may be used to adjust the maximum parallelism. Only increase this value with great care since you run the risk of overloading servers and making yourself unpopular with data centres. As a rule, you should only increase this value if you have obtained permission from the data centres whose services on which you will be using the increased parallelism.
    
    See Also:
    
    DEFAULT_MAXPAR, getMaxParallelism(), Constant Field Values
- Constructor Detail
  - ParallelResultRowSequence
```
public ParallelResultRowSequence(ConeQueryRowSequence querySeq,
                                 ConeSearcher coneSearcher,
                                 ConeErrorPolicy errAct,
                                 Coverage coverage,
                                 boolean bestOnly,
                                 boolean distFilter,
                                 java.lang.String distanceCol,
                                 int parallelism)
```
    Constructor.
    
    Parameters:
    
    querySeq - sequence providing cone search query parameters
    
    coneSearcher - cone search implementation
    
    errAct - defines action on cone search invocation error
    
    coverage - coverage for results, or null
    
    bestOnly - whether all results or just best are required
    
    distFilter - true to perform post-query filtering on results based on the distance between the query position and the result row position
    
    distanceCol - name of column to hold distance information in output table, or null
    
    parallelism - number of concurrent querying threads
- Method Detail
  - next
```
public boolean next()
             throws java.io.IOException
```
    Specified by:
    
    next in interface uk.ac.starlink.table.RowSequence
    
    Throws:
    
    java.io.IOException
  - getCell
```
public java.lang.Object getCell(int icol)
                         throws java.io.IOException
```
    Specified by:
    
    getCell in interface uk.ac.starlink.table.RowSequence
    
    Throws:
    
    java.io.IOException
  - getRow
```
public java.lang.Object[] getRow()
                          throws java.io.IOException
```
    Specified by:
    
    getRow in interface uk.ac.starlink.table.RowSequence
    
    Throws:
    
    java.io.IOException
  - getRa
```
public double getRa()
             throws java.io.IOException
```
    Description copied from interface: ConeQueryRowSequence
    
    Get central right ascension for the current row's cone search request in degrees.
    
    Specified by:
    
    getRa in interface ConeQueryRowSequence
    
    Returns:
    
    right ascension
    
    Throws:
    
    java.io.IOException
  - getDec
```
public double getDec()
              throws java.io.IOException
```
    Description copied from interface: ConeQueryRowSequence
    
    Get central declination for the current row's cone search request in degrees.
    
    Specified by:
    
    getDec in interface ConeQueryRowSequence
    
    Returns:
    
    declination
    
    Throws:
    
    java.io.IOException
  - getRadius
```
public double getRadius()
                 throws java.io.IOException
```
    Description copied from interface: ConeQueryRowSequence
    
    Get search radius for the current row's cone search request in degrees.
    
    Specified by:
    
    getRadius in interface ConeQueryRowSequence
    
    Returns:
    
    search radius
    
    Throws:
    
    java.io.IOException
  - getIndex
```
public long getIndex()
              throws java.io.IOException
```
    Description copied from interface: ConeQueryRowSequence
    
    Get the index in the underlying table to which the current row relates. The identity of this underlying table is not specified by this interface, but must be understood by the creator and user of instances. In particular, the return value does not necessarily increment by one for each call to next.
    
    Specified by:
    
    getIndex in interface ConeQueryRowSequence
    
    Returns:
    
    row index
    
    Throws:
    
    java.io.IOException
  - getConeResult
```
public uk.ac.starlink.table.StarTable getConeResult()
                                             throws java.io.IOException
```
    Description copied from interface: ConeResultRowSequence
    
    Returns the result of the cone search for the current row of this sequence. The work will typically be done using ConeMatcher.getConeResult(uk.ac.starlink.ttools.cone.ConeSearcher, uk.ac.starlink.ttools.cone.ConeErrorPolicy, boolean, boolean, java.lang.String, double, double, double).
    If no records in the cone are found, the return value may either be null or (preferably) an empty table with the correct columns.
    
    Specified by:
    
    getConeResult in interface ConeResultRowSequence
    
    Returns:
    
    table giving rows strictly within the match criteria for the current row of this cone query sequence, or null
    
    Throws:
    
    java.io.IOException
  - close
```
public void close()
           throws java.io.IOException
```
    Specified by:
    
    close in interface uk.ac.starlink.table.RowSequence
    
    Throws:
    
    java.io.IOException
  - getMaxParallelism
```
public static int getMaxParallelism()
```
    Returns the maximum parallelism value which should permitted in this JVM. The purpose of this is to set a limit to the number of concurrent queries that an irresponsible/careless user can hit a server with. The value can be adjusted using the MAXPAR_PROP system property. Note that this method is not used by this class, i.e. the maximum is not imposed here, it should be imposed by calling code.
    
    Returns:
    
    parallelism limit

Class ParallelResultRowSequence

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_MAXPAR

MAXPAR_PROP

Constructor Detail

ParallelResultRowSequence

Method Detail

next

getCell

getRow

getRa

getDec

getRadius

getIndex

getConeResult

close

getMaxParallelism