Class DefaultValueInfo
- java.lang.Object
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- uk.ac.starlink.table.DefaultValueInfo
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- All Implemented Interfaces:
ValueInfo
- Direct Known Subclasses:
ColumnInfo
public class DefaultValueInfo extends java.lang.Object implements ValueInfo
Default implementation of the ValueInfo interface. Additionally provides mutator methods for the accessors defined in ValueInfo.- Author:
- Mark Taylor (Starlink)
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Constructor Summary
Constructors Constructor Description DefaultValueInfo()
Constructs a new generic DefaultValueInfo object without a name.DefaultValueInfo(java.lang.String name)
Constructs a new generic DefaultValueInfo object with a given name.DefaultValueInfo(java.lang.String name, java.lang.Class contentClass)
Constructs a new DefaultValueInfo object with a given name and class.DefaultValueInfo(java.lang.String name, java.lang.Class contentClass, java.lang.String description)
Constructs a new DefaultValueInfo object with a given name, class and description.DefaultValueInfo(ValueInfo base)
Constructs a DefaultValueInfo object which is a copy of an existing one.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static java.lang.String
formatClass(java.lang.Class clazz)
Returns a human-friendly string indicating the class and shape of a given class object.static java.lang.String
formatShape(int[] shape)
Returns a string representing the shape of this object, if it is array-like.java.lang.String
formatValue(java.lang.Object value, int maxLength)
Returns a string representation of a given value described by this ValueInfo.static ValueInfo
generalise(ValueInfo vi1, ValueInfo vi2)
Returns a ValueInfo object which is sufficiently general to cover every object described by either of two given ValueInfo objects.java.lang.Class
getContentClass()
Returns the java class of the values described by this object.java.lang.String
getDescription()
Returns a description of the values described by this object.DomainMapper[]
getDomainMappers()
Returns an array of objects which may be able to convert from the values described by this info to a particular target value domain.int
getElementSize()
May indicate the size of a value element stored as the value of this info.java.lang.String
getName()
Returns the name of this object.int[]
getShape()
Returns the shape associated with array value types.java.lang.String
getUCD()
Returns the Unified Column Descriptor string applying to the values described by this object.java.lang.String
getUnitString()
Returns a string representing the units of the values described by this object.java.lang.String
getUtype()
Returns the Utype string applying to the values described by this object.boolean
isArray()
Indicates whether the values described by this object are java arrays.boolean
isNullable()
Indicates whether values returned described by this object may have the value null.void
setContentClass(java.lang.Class contentClass)
Sets the java class of objects contained in this column.void
setDescription(java.lang.String description)
Sets a textual description of the values described by this object.void
setDomainMappers(DomainMapper[] domainMappers)
Sets the domain mappers known for this object.void
setElementSize(int size)
Sets the element size of values described by this object.void
setName(java.lang.String name)
Sets the name for this object.void
setNullable(boolean isNullable)
Sets whether values described by this object may have the value null.void
setShape(int[] shape)
Sets the shape of values described by this object.void
setUCD(java.lang.String ucd)
Sets the Unified Content Descriptor string applying to values described by this object.void
setUnitString(java.lang.String unitString)
Sets the string representing the units for the values described by this object.void
setUtype(java.lang.String utype)
Sets the Utype string applying to values described by this object.java.lang.String
toString()
Returns a string representation of this object.static int[]
unformatShape(java.lang.String txt)
Takes a stringified version of the shape and turns it into an array.java.lang.Object
unformatString(java.lang.String rep)
Returns an object of the sort described by this ValueInfo represented by the given string rep.
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Constructor Detail
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DefaultValueInfo
public DefaultValueInfo()
Constructs a new generic DefaultValueInfo object without a name.
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DefaultValueInfo
public DefaultValueInfo(java.lang.String name)
Constructs a new generic DefaultValueInfo object with a given name.- Parameters:
name
- the name applying to described values
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DefaultValueInfo
public DefaultValueInfo(java.lang.String name, java.lang.Class contentClass)
Constructs a new DefaultValueInfo object with a given name and class.- Parameters:
name
- the name applying to described valuescontentClass
- the class of which described values should be instances
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DefaultValueInfo
public DefaultValueInfo(java.lang.String name, java.lang.Class contentClass, java.lang.String description)
Constructs a new DefaultValueInfo object with a given name, class and description.- Parameters:
name
- the name applying to described valuescontentClass
- the class of which described values should be instancesdescription
- a textual description of the described values
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DefaultValueInfo
public DefaultValueInfo(ValueInfo base)
Constructs a DefaultValueInfo object which is a copy of an existing one. The fields of the new object are copies (where possible not references to) those of the base one.- Parameters:
base
- the object to copy
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Method Detail
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setName
public void setName(java.lang.String name)
Sets the name for this object.- Parameters:
name
- the name
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getName
public java.lang.String getName()
Description copied from interface:ValueInfo
Returns the name of this object.
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setUnitString
public void setUnitString(java.lang.String unitString)
Sets the string representing the units for the values described by this object.- Parameters:
unitString
- a string giving the units, or null if units are unknown
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getUnitString
public java.lang.String getUnitString()
Description copied from interface:ValueInfo
Returns a string representing the units of the values described by this object. The syntax and conventions should ideally match those adopted by VOTable, as defined by CDS.- Specified by:
getUnitString
in interfaceValueInfo
- Returns:
- a string giving the units, or null if units are unknown
- See Also:
- Standards for Astronomical Catalogues: Units, CDS Strasbourg
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setUCD
public void setUCD(java.lang.String ucd)
Sets the Unified Content Descriptor string applying to values described by this object.- Parameters:
ucd
- the UCD, or null if none is known
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getUCD
public java.lang.String getUCD()
Description copied from interface:ValueInfo
Returns the Unified Column Descriptor string applying to the values described by this object.- Specified by:
getUCD
in interfaceValueInfo
- Returns:
- the UCD, or null if none is known
- See Also:
- Unified
Column Descriptor scheme,
UCD
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setUtype
public void setUtype(java.lang.String utype)
Sets the Utype string applying to values described by this object.- Parameters:
utype
- the Utype, ornull
if none is known
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getUtype
public java.lang.String getUtype()
Description copied from interface:ValueInfo
Returns the Utype string applying to the values described by this object. Utype is a string which references a data model. It is used pervasively within IVOA standards; probably an official IVOA definition of Utype syntax and semantics will arise one day.
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setDescription
public void setDescription(java.lang.String description)
Sets a textual description of the values described by this object.- Parameters:
description
- a texttual description of this column, or the empty string "" if there is nothing to be said
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getDescription
public java.lang.String getDescription()
Description copied from interface:ValueInfo
Returns a description of the values described by this object. It may contain a short or long textual description of the kind of information represented by the value.- Specified by:
getDescription
in interfaceValueInfo
- Returns:
- a textual description, or the empty string "" if there is nothing to be said
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getContentClass
public java.lang.Class getContentClass()
Description copied from interface:ValueInfo
Returns the java class of the values described by this object. The intention is that any Object described by this ValueInfo will be an instance of the returned class or one of its subclasses. Note therefore that it must not return one of the primitive class objects (int.class et al.); the appropriate wrapper classes must be used instead (Integer.class etc).The class returned should not under normal circumstances be an array of arrays; to express multidimensionality of arrays you should store an array of non-array objects or of primitives and provide shape information via the getShape method. There is nothing to stop you describing arrays of arrays with a ValueInfo, but some other elements of the tables infrastructure and applications may work on the assumption that such objects are not present.
Note that to store sets of more than 231 items it will be necessary to use some custom object, since java arrays are indexed by type int.
- Specified by:
getContentClass
in interfaceValueInfo
- Returns:
- the java class
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setContentClass
public void setContentClass(java.lang.Class contentClass)
Sets the java class of objects contained in this column.- Parameters:
contentClass
- the class of items in this column- Throws:
java.lang.IllegalArgumentException
- if contentClass is primitive
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isArray
public boolean isArray()
Description copied from interface:ValueInfo
Indicates whether the values described by this object are java arrays. This convenience method should return the same asgetContentClass().getComponentType()!=null
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getShape
public int[] getShape()
Description copied from interface:ValueInfo
Returns the shape associated with array value types. If the class returned byValueInfo.getContentClass()
is a java array type, the return from this method may contain information about the shape of the rectangular array which this represents. The dimensions of the array are given in the elements of the return value of this method, fastest varying first. All elements of the array should be positive, except that the last (slowest varying) element may be <=0 (conventionally -1) to indicate that the number of (shape.length-1)-dimensional slices contained in the value is not known. If nothing is known about the shape of the array values, then a 1-element array whose only element is <=0 should be returned.If getContentClass does not give an array type (hence isArray returns false) the return value for this method is undefined (but should probably be null).
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setShape
public void setShape(int[] shape)
Sets the shape of values described by this object.- Parameters:
shape
- the shape- Throws:
java.lang.IllegalArgumentException
- if shape has elements apart from the last one which are <=0
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getElementSize
public int getElementSize()
Description copied from interface:ValueInfo
May indicate the size of a value element stored as the value of this info. The total size of the value will in this case be the return value of this method multiplied by the number of elements, as indicated byValueInfo.getShape()
(or by 1, if getShape is null).The exact meaning of the value returned is dependent on this ValueInfo. This method was introduced to return the maximum number of characters in a String-class ValueInfo; this information is necessary for writing out to certain formats (FITS). Other ValueInfo types however may use it for their own purposes.
ValueInfo instances which decline to supply this information should return -1 from this method.
- Specified by:
getElementSize
in interfaceValueInfo
- Returns:
- notional size of each element an array of values described by this info
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setElementSize
public void setElementSize(int size)
Sets the element size of values described by this object.- Parameters:
size
- the element size
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isNullable
public boolean isNullable()
Description copied from interface:ValueInfo
Indicates whether values returned described by this object may have the value null. In general this should return true, which implies no assertion about the return values (they may or may not be null). But if the values are known never to be null, it may return false.- Specified by:
isNullable
in interfaceValueInfo
- Returns:
- false if values are guaranteed non-null
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setNullable
public void setNullable(boolean isNullable)
Sets whether values described by this object may have the value null. By setting this to false you assert that no null objects will be returned from this column.- Parameters:
isNullable
- false if objects in this column are guaranteed non-null
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getDomainMappers
public DomainMapper[] getDomainMappers()
Description copied from interface:ValueInfo
Returns an array of objects which may be able to convert from the values described by this info to a particular target value domain. This can used for non-obvious representations of certain coordinates such as time and angular position. In most cases the returned array will be empty, since the target domain is obvious (e.g. numeric values). In the (unusual) case that the returned array contains multiple entries, it should have no more than one for any given target domain, and the first entry may be considered "primary" in some sense. Absence of a mapper for a given target domain does not necessarily indicate that the described values cannot be used in that domain.- Specified by:
getDomainMappers
in interfaceValueInfo
- Returns:
- array of domain mappers for the values described by this info
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setDomainMappers
public void setDomainMappers(DomainMapper[] domainMappers)
Sets the domain mappers known for this object.- Parameters:
domainMappers
- new domain mapper array
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generalise
public static ValueInfo generalise(ValueInfo vi1, ValueInfo vi2)
Returns a ValueInfo object which is sufficiently general to cover every object described by either of two given ValueInfo objects. For most of the info attributes this entails setting to null any attribute which is not the same for both, though for contentClass it involves finding the most specific common ancestor class.- Parameters:
vi1
- one ValueInfo objectvi2
- the other ValueInfo object- Returns:
- a generalised ValueInfo object
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formatValue
public java.lang.String formatValue(java.lang.Object value, int maxLength)
Description copied from interface:ValueInfo
Returns a string representation of a given value described by this ValueInfo. The returned string should be no longer than a given maximum length.- Specified by:
formatValue
in interfaceValueInfo
- Parameters:
value
- the value to representmaxLength
- the maximum number of characters in the returned string
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formatClass
public static java.lang.String formatClass(java.lang.Class clazz)
Returns a human-friendly string indicating the class and shape of a given class object. This will read something like "Integer" or "byte[][]" or "uk.ac.starlink.FrameSet".- Parameters:
clazz
- the class- Returns:
- a string showing the class and shape of clazz
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formatShape
public static java.lang.String formatShape(int[] shape)
Returns a string representing the shape of this object, if it is array-like. This will look something like "1024,1024,3" or "2,*".- Parameters:
shape
- the shape to format- Returns:
- a human-readable representation of the value shape
- See Also:
unformatShape(String)
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unformatShape
public static int[] unformatShape(java.lang.String txt)
Takes a stringified version of the shape and turns it into an array. This performs the opposite offormatShape(int[])
, so values are comma-separated, and the last one only may be "*".- Parameters:
txt
- string representation of value shape- Returns:
- array representation of value shape
- Throws:
java.lang.IllegalArgumentException
- if the argument is not in a comprehensible format- See Also:
formatShape(int[])
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unformatString
public java.lang.Object unformatString(java.lang.String rep)
Description copied from interface:ValueInfo
Returns an object of the sort described by this ValueInfo represented by the given string rep.- Specified by:
unformatString
in interfaceValueInfo
- Parameters:
rep
- the string representation of a value described by this ValueInfo- Returns:
- the Object value represented by rep; must match this info's content class (or be null)
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toString
public java.lang.String toString()
Returns a string representation of this object. The result indicates the object's name, class and shape.- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string representation of this object
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