Package uk.ac.starlink.ttools.jel
Class StarTableJELRowReader
- java.lang.Object
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- gnu.jel.DVMap
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- uk.ac.starlink.ttools.jel.JELRowReader
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- uk.ac.starlink.ttools.jel.StarTableJELRowReader
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- Direct Known Subclasses:
DummyJELRowReader
,RandomJELRowReader
,SequentialJELRowReader
public abstract class StarTableJELRowReader extends JELRowReader
JELRowReader subclass for access to StarTables.In addition to the syntax provided by the superclass, the following symbols are understood:
- "$0" or "$index" or (deprecated) "index" (case insensitive):
- the 1-based index of the current row.
- "$ncol"
- Number of columns in the table.
- "$nrow"
- Number of rows in the table. If this is not known, a null value is returned.
- Parameter names:
- The string "param$" followed by the name of a table parameter (case-insensitive) is a constant for the table (as a primitive, if applicable). This can only work if the parameter name is a legal java identifier.
- UCD specifiers:
- The string "ucd$" followed by the text of a UCD giving the required value. Any punctuation (such as ".", ";", "-") in the UCD should be replaced with a "_" (since these symbols cannot appear in identifiers). If the identifier has a trailing "_", then any UCD which starts as specified is considered to match. The first matching column, or if there is none the first matching parameter value is returned. UCD matching is case-insensitive.
- Utype specifiers:
- The string "utype$" followed by the text of a Utype identifying the required value. Any punctuation (such as ".", ":", "-") in the Utype should be replaced with a "_" (since these symbols cannot appear in identifiers). The first matching column, or if there is none the first matching parameter value is returned. UType matching is case-insensitive.
- "$random" (case insensitive) or (deprecated) "RANDOM":
- The special token "$random" evaluates to a double-precision random
number
0<=x<1
which is constant for a given row within this reader. The quality of the random numbers may not be particularly good.
- Since:
- 7 Dec 2007
- Author:
- Mark Taylor
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Field Summary
Fields Modifier and Type Field Description static java.lang.String
PARAM_PREFIX
The string which should be prefixed to a table parameter (constant) name to result in substituting its value.static java.lang.String
UCD_PREFIX
A string to prefix to a UCD string to indicate the column/parameter with that UCD.static java.lang.String
UTYPE_PREFIX
A string to prefix to a Utype string to indicate the column/parameter with that Utype.-
Fields inherited from class uk.ac.starlink.ttools.jel.JELRowReader
COLUMN_ID_CHAR, NULL_QUERY_PREFIX, OBJECT_PREFIX
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Constructor Summary
Constructors Constructor Description StarTableJELRowReader(uk.ac.starlink.table.StarTable table)
Constructs a new row reader for a given StarTable.
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected Constant<?>
createDescribedValueConstant(uk.ac.starlink.table.DescribedValue dval)
Returns a Constant object based on a DescribedValue.protected boolean
getBooleanColumnValue(int icol)
Returns a boolean value for a cell of the current row.protected byte
getByteColumnValue(int icol)
Returns a byte value for a cell of the current row.protected abstract java.lang.Object
getCell(int icol)
Returns the value for a given column in this reader's table at the current row.protected char
getCharColumnValue(int icol)
Returns a char value for a cell of the current row.protected java.lang.Class<?>
getColumnClass(int icol)
Returns the class of values returned by a given column.protected int
getColumnIndexByName(java.lang.String name)
Returns the column index of a column in the row given its name.protected Constant<?>
getConstantByName(java.lang.String name)
Understands table parameters identified case-insensitively by name (using thePARAM_PREFIX
prefix) or by UCD (using theUCD_PREFIX
prefix) or by Utype (using theUTYPE_PREFIX
prefix).abstract long
getCurrentRow()
Returns the index of the row on which evaluations are currently taking place.protected double
getDoubleColumnValue(int icol)
Returns a double value for a cell of the current row.protected float
getFloatColumnValue(int icol)
Returns a float value for a cell of the current row.protected int
getIntColumnValue(int icol)
Returns a int value for a cell of the current row.protected long
getLongColumnValue(int icol)
Returns a long value for a cell of the current row.protected java.lang.Object
getObjectColumnValue(int icol)
Returns an Object value for a cell of the current row.protected short
getShortColumnValue(int icol)
Returns a short value for a cell of the current row.protected Constant<?>
getSpecialByName(java.lang.String name)
Adds to the superclass implementation the following: "$0", "index" or "$index" gives the (1-based) row number "$ncol" gives the number of columns in the table "$nrow" gives the number of rows in the table (null if unknown) "$random" or "RANDOM" returns a double random number, always the same for a given rowuk.ac.starlink.table.StarTable
getTable()
Returns the table associated with this reader.static java.util.regex.Pattern
getUcdRegex(java.lang.String ucd)
Takes a (non-prefixed) UCD specification and returns a Pattern actual UCDs should match if they represent the same thing.static java.util.regex.Pattern
getUtypeRegex(java.lang.String utype)
Takes a (non-prefixed) Utype specification and returns a Pattern actual Utypes should match if they represent the same thing.protected boolean
isBlank(int icol)
Indicates whether the value in a given column is null.boolean
requiresRowIndex()
Indicates whether this RowReader has been asked to reference any constants for which the row index is required.-
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, getTypeName, setFailOnNull, stripPrefix, translate
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Field Detail
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PARAM_PREFIX
public static final java.lang.String PARAM_PREFIX
The string which should be prefixed to a table parameter (constant) name to result in substituting its value.- See Also:
- Constant Field Values
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UCD_PREFIX
public static final java.lang.String UCD_PREFIX
A string to prefix to a UCD string to indicate the column/parameter with that UCD. The first matching column, else the first matching parameter, is used. Punctuation in the UCD name is all mapped to "_". A trailing "_" corresponds to a wildcard.- See Also:
- Constant Field Values
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UTYPE_PREFIX
public static final java.lang.String UTYPE_PREFIX
A string to prefix to a Utype string to indicate the column/parameter with that Utype. The first matching column, else the first matching parameter, is used. Punctuation in the Utype name is all mapped to "_".- See Also:
- Constant Field Values
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Constructor Detail
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StarTableJELRowReader
public StarTableJELRowReader(uk.ac.starlink.table.StarTable table)
Constructs a new row reader for a given StarTable. Note that this reader cannot become aware of changes to the columns of the table; in the event of such changes this object should be dicarded and and a new one used for any new expressions.- Parameters:
table
- the StarTable this reader will read from
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Method Detail
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getTable
public uk.ac.starlink.table.StarTable getTable()
Returns the table associated with this reader.- Returns:
- table
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getCell
protected abstract java.lang.Object getCell(int icol) throws java.io.IOException
Returns the value for a given column in this reader's table at the current row.- Parameters:
icol
- column index- Returns:
- contents of column icol at the current row
- Throws:
java.io.IOException
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getCurrentRow
public abstract long getCurrentRow()
Returns the index of the row on which evaluations are currently taking place.- Returns:
- row index (first row is 0)
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requiresRowIndex
public boolean requiresRowIndex()
Indicates whether this RowReader has been asked to reference any constants for which the row index is required. In practice this means it will return true if any of the JEL expressions which this RowReader has been asked to compile may need to call thegetCurrentRow()
method. Since not all row reader implementations are able to return a value for that method, this is useful information.- Returns:
- true if the current row index may be required during evaluation
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isBlank
protected boolean isBlank(int icol)
Description copied from class:JELRowReader
Indicates whether the value in a given column is null.- Specified by:
isBlank
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- true if value at icol is null
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getColumnClass
protected java.lang.Class<?> getColumnClass(int icol)
Description copied from class:JELRowReader
Returns the class of values returned by a given column. If no column with the given index exists, null should be returned.- Specified by:
getColumnClass
in classJELRowReader
- Parameters:
icol
- non-negative column index- Returns:
- value class, or null for non-existent column
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getColumnIndexByName
protected int getColumnIndexByName(java.lang.String name)
Description copied from class:JELRowReader
Returns the column index of a column in the row given its name. Ifname
does not refer to any known column, return -1.- Specified by:
getColumnIndexByName
in classJELRowReader
- Parameters:
name
- column name- Returns:
- column index, or -1
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getConstantByName
protected Constant<?> getConstantByName(java.lang.String name)
Understands table parameters identified case-insensitively by name (using thePARAM_PREFIX
prefix) or by UCD (using theUCD_PREFIX
prefix) or by Utype (using theUTYPE_PREFIX
prefix).- Specified by:
getConstantByName
in classJELRowReader
- Parameters:
name
- constant name- Returns:
- constant, or null
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getSpecialByName
protected Constant<?> getSpecialByName(java.lang.String name)
Adds to the superclass implementation the following:- "$0", "index" or "$index" gives the (1-based) row number
- "$ncol" gives the number of columns in the table
- "$nrow" gives the number of rows in the table (null if unknown)
- "$random" or "RANDOM" returns a double random number, always the same for a given row
- Overrides:
getSpecialByName
in classJELRowReader
- Parameters:
name
- special name- Returns:
- special, or null
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createDescribedValueConstant
protected Constant<?> createDescribedValueConstant(uk.ac.starlink.table.DescribedValue dval)
Returns a Constant object based on a DescribedValue. The supplied implementation evaluates the constant's class and value once when this method is called.- Parameters:
dval
- described value object- Returns:
- constant which evaluates to dval's value
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getBooleanColumnValue
protected boolean getBooleanColumnValue(int icol)
Description copied from class:JELRowReader
Returns a boolean value for a cell of the current row. Will only be called if the relevant column is declared boolean. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getBooleanColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getByteColumnValue
protected byte getByteColumnValue(int icol)
Description copied from class:JELRowReader
Returns a byte value for a cell of the current row. Will only be called if the relevant column is declared byte. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getByteColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getCharColumnValue
protected char getCharColumnValue(int icol)
Description copied from class:JELRowReader
Returns a char value for a cell of the current row. Will only be called if the relevant column is declared char. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getCharColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getShortColumnValue
protected short getShortColumnValue(int icol)
Description copied from class:JELRowReader
Returns a short value for a cell of the current row. Will only be called if the relevant column is declared short. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getShortColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getIntColumnValue
protected int getIntColumnValue(int icol)
Description copied from class:JELRowReader
Returns a int value for a cell of the current row. Will only be called if the relevant column is declared int. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getIntColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getLongColumnValue
protected long getLongColumnValue(int icol)
Description copied from class:JELRowReader
Returns a long value for a cell of the current row. Will only be called if the relevant column is declared long. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getLongColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getFloatColumnValue
protected float getFloatColumnValue(int icol)
Description copied from class:JELRowReader
Returns a float value for a cell of the current row. Will only be called if the relevant column is declared float. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getFloatColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getDoubleColumnValue
protected double getDoubleColumnValue(int icol)
Description copied from class:JELRowReader
Returns a double value for a cell of the current row. Will only be called if the relevant column is declared double. Must callJELRowReader.foundNull()
(and return any value) if the result is null.- Specified by:
getDoubleColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getObjectColumnValue
protected java.lang.Object getObjectColumnValue(int icol)
Description copied from class:JELRowReader
Returns an Object value for a cell of the current row.- Specified by:
getObjectColumnValue
in classJELRowReader
- Parameters:
icol
- column index- Returns:
- value
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getUcdRegex
public static java.util.regex.Pattern getUcdRegex(java.lang.String ucd)
Takes a (non-prefixed) UCD specification and returns a Pattern actual UCDs should match if they represent the same thing. Punctuation is mapped to underscores, and the pattern is case-insensitive, which means that the same syntax can work for UCD1s and UCD1+s. If a trailing underscore (or other punctuation mark) is present in the inputucd
it is considered as a trailing match-all wildcard.- Parameters:
ucd
- UCD1 or UCD1+ specification/pattern- Returns:
- regular expression pattern which matches actual UCD1s or UCD1+s
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getUtypeRegex
public static java.util.regex.Pattern getUtypeRegex(java.lang.String utype)
Takes a (non-prefixed) Utype specification and returns a Pattern actual Utypes should match if they represent the same thing. Punctuation is mapped to underscores, and the pattern is case-insensitive.- Parameters:
utype
- utype specification- Returns:
- regular expression pattern which matches actual Utypes
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