uk.ac.starlink.topcat

Class TopcatJELRowReader

java.lang.Object

gnu.jel.DVMap

uk.ac.starlink.ttools.jel.JELRowReader

uk.ac.starlink.ttools.jel.StarTableJELRowReader

uk.ac.starlink.ttools.jel.RandomJELRowReader

uk.ac.starlink.topcat.TopcatJELRowReader

public abstract class TopcatJELRowReader
extends uk.ac.starlink.ttools.jel.RandomJELRowReader

Random JELRowReader with which recognises some expressions in addition to those of the superclass.

Row Subset _ID identifiers:

The character '_' followed by the 1-based index of a defined row subset returns true iff the current row is part of the subset.

Row Subset names:

The name of a subset (case-insensitive) returns true iff the current row is part of the named subset.

Apparent table index:

The tokens "$index0" or "$00" (case insensitive) are evaluated as the index of the current row in the apparent table; this differs from $index/$0 if a non-default sort order or current subset is in force.

Apparent table row count:

The token "$nrow0" is the number of rows in the apparent table; this differs from $nrow if a non-default current subset is in force.

Apparent table column count:

The token "$ncol0 is the number of columns in the apparent table; this differs from $ncol if some columns are hidden.

Since:

8 Feb 2005

Author:

Mark Taylor (Starlink)

Field Summary

Fields

Modifier and Type	Field and Description
static char	SUBSET_ID_CHAR Prefix identifying a unique subset identifier.

Fields inherited from class uk.ac.starlink.ttools.jel.StarTableJELRowReader

PARAM_PREFIX, UCD_PREFIX, UTYPE_PREFIX

Fields inherited from class uk.ac.starlink.ttools.jel.JELRowReader

COLUMN_ID_CHAR, NULL_QUERY_PREFIX, OBJECT_PREFIX

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TopcatJELRowReader(TopcatModel tcModel) Constructs a new row reader for a TopcatModel.

Method Summary

Modifier and Type	Method and Description
static TopcatJELRowReader	createAccessReader(TopcatModel tcModel) Returns a reader that uses a RowAccess object from the TopcatModel's data model.
static TopcatJELRowReader	createConcurrentReader(TopcatModel tcModel) Returns a reader that uses the threadsafe random access methods of the TopcatModel's data model.
protected uk.ac.starlink.ttools.jel.Constant<?>	createDescribedValueConstant(uk.ac.starlink.table.DescribedValue dval) Returns a constant which is evaluated at runtime.
static TopcatJELRowReader	createDummyReader(TopcatModel tcModel) Returns a reader that doesn't do any actual data access.
abstract boolean	evaluateBooleanAtRow(gnu.jel.CompiledExpression compEx, long lrow) Evaluates a given compiled expression of boolean return type at a given row.
boolean	getBooleanProperty(short isub) Returns the actual subset value for the current row and a given column.
protected uk.ac.starlink.ttools.jel.Constant<?>	getSpecialByName(String name)
TopcatModel	getTopcatModel() Returns the topcat model on which this row reader is based.
int[]	getTranslatedSubsetIds() Returns a set (no duplicated elements) of the subset IDs for which this RowReader has been asked to provide translation values.
String	getTypeName(String name) Overrides superclass implementation to recognise row subsets by name or _ID.
Object	translate(String name) Overrides superclass implementation to recognise subsets as well as the other special objects.

Methods inherited from class uk.ac.starlink.ttools.jel.RandomJELRowReader

createAccessReader, createAccessReader, createConcurrentReader, evaluateAtRow

Methods inherited from class uk.ac.starlink.ttools.jel.StarTableJELRowReader

getBooleanColumnValue, getByteColumnValue, getCell, getCharColumnValue, getColumnClass, getColumnIndexByName, getConstantByName, getCurrentRow, getDescribedValueByName, getDoubleColumnValue, getFloatColumnValue, getIntColumnValue, getLongColumnValue, getObjectColumnValue, getShortColumnValue, getTable, getUcdRegex, getUtypeRegex, isBlank, requiresRowIndex, valueDouble, valueInt, valueLong, valueObject, valueString

Methods inherited from class uk.ac.starlink.ttools.jel.JELRowReader

evaluate, evaluateBoolean, evaluateDouble, foundNull, getBooleanArrayProperty, getBooleanProperty, getBooleanProperty, getBooleanValue, getByteArrayProperty, getByteProperty, getByteValue, getCharArrayProperty, getCharProperty, getCharValue, getColumnIndex, getDateArrayProperty, getDoubleArrayProperty, getDoubleProperty, getDoubleValue, getFloatArrayProperty, getFloatProperty, getFloatValue, getIntArrayProperty, getIntProperty, getIntValue, getLongArrayProperty, getLongProperty, getLongValue, getNumberProperty, getObjectArrayProperty, getObjectProperty, getShortArrayProperty, getShortProperty, getShortValue, getStringArrayProperty, getStringProperty, getTranslatedColumns, getTranslatedConstants, setFailOnNull, stripPrefix

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SUBSET_ID_CHAR

public static final char SUBSET_ID_CHAR

Prefix identifying a unique subset identifier.

See Also:

Constant Field Values

Constructor Detail

TopcatJELRowReader

protected TopcatJELRowReader(TopcatModel tcModel)

Constructs a new row reader for a TopcatModel.

Parameters:

tcModel - topcat model

Method Detail

getTopcatModel

public TopcatModel getTopcatModel()

Returns the topcat model on which this row reader is based.

Returns:

topcat model

evaluateBooleanAtRow

public abstract boolean evaluateBooleanAtRow(gnu.jel.CompiledExpression compEx,
                                             long lrow)
                                      throws Throwable

Evaluates a given compiled expression of boolean return type at a given row.

Parameters:

compEx - compiled boolean expression

lrow - row at which to evaluate

Returns:

expression value

Throws:

Throwable

getTypeName

public String getTypeName(String name)

Overrides superclass implementation to recognise row subsets by name or _ID.

Overrides:

getTypeName in class uk.ac.starlink.ttools.jel.JELRowReader

Parameters:

name - the variable name

Returns:

corresponding method name fragment

See Also:

"JEL manual"

translate

public Object translate(String name)

Overrides superclass implementation to recognise subsets as well as the other special objects. The additional return type is:

• a Short (the subset index) if the column specification appears to reference a known row subset

Overrides:

translate in class uk.ac.starlink.ttools.jel.JELRowReader

Parameters:

name - the name of the variable-like object to evaluate

Returns:

a numeric object corresponding to an object which we know how to evaluate

See Also:

"JEL manual"

getTranslatedSubsetIds

public int[] getTranslatedSubsetIds()

Returns a set (no duplicated elements) of the subset IDs for which this RowReader has been asked to provide translation values. In practice that means the ID (in the sense of the OptionsListModel returned by TopcatModel.getSubsets) of every RowSubset which has been directly referenced in a JEL expression which this RowReader has been used to compile.

Returns:

list of distinct subset IDs which this row reader has had to reference in compiling JEL expressions

getBooleanProperty

public boolean getBooleanProperty(short isub)

Returns the actual subset value for the current row and a given column.

Parameters:

isub - index of the subset to evaluate at the current row

Returns:

result of the isIncluded method of the RowSubset indicated at the current row

getSpecialByName

protected uk.ac.starlink.ttools.jel.Constant<?> getSpecialByName(String name)

Overrides:

getSpecialByName in class uk.ac.starlink.ttools.jel.StarTableJELRowReader

createDescribedValueConstant

protected uk.ac.starlink.ttools.jel.Constant<?> createDescribedValueConstant(uk.ac.starlink.table.DescribedValue dval)

Returns a constant which is evaluated at runtime. This is more appropriate than the inherited (evaluate at call time) behaviour, since within TOPCAT the constant's value may change as a result of user intervention during the lifetime of the returned object.

Overrides:

createDescribedValueConstant in class uk.ac.starlink.ttools.jel.StarTableJELRowReader

createConcurrentReader

public static TopcatJELRowReader createConcurrentReader(TopcatModel tcModel)

Returns a reader that uses the threadsafe random access methods of the TopcatModel's data model.

Parameters:

tcModel - topcat model

Returns:

threadsafe row reader

createAccessReader

public static TopcatJELRowReader createAccessReader(TopcatModel tcModel)

Returns a reader that uses a RowAccess object from the TopcatModel's data model.

Parameters:

tcModel - topcat model

Returns:

row reader suitable for use only within a single thread

createDummyReader

public static TopcatJELRowReader createDummyReader(TopcatModel tcModel)

Returns a reader that doesn't do any actual data access. Suitable for testing compilation success etc.

Parameters:

tcModel - topcat model

Returns:

row reader that throws UnsupportedOperationException for data access methods