Class DefaultValueInfo

  • 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)
    • 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.
    • 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.util.List<DescribedValue> getAuxData()
      Returns a list of auxiliary metadata objects pertaining to this column.
      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.
      java.lang.String getXtype()
      Returns the Xtype 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 setAuxData​(java.util.List<DescribedValue> auxData)
      Sets the list of auxiliary metadata items for this column.
      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.
      void setXtype​(java.lang.String xtype)
      Sets the Xtype 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.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Constructor Detail

      • DefaultValueInfo

        public DefaultValueInfo()
        Constructs a new generic DefaultValueInfo object without a name.
      • 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
      • 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 values
        contentClass - the class of which described values should be instances
      • 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 values
        contentClass - the class of which described values should be instances
        description - a textual description of the described values
      • 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
    • Method Detail

      • setName

        public void setName​(java.lang.String name)
        Sets the name for this object.
        Parameters:
        name - the name
      • getName

        public java.lang.String getName()
        Description copied from interface: ValueInfo
        Returns the name of this object.
        Specified by:
        getName in interface ValueInfo
        Returns:
        the name
      • 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
      • 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 interface ValueInfo
        Returns:
        a string giving the units, or null if units are unknown
        See Also:
        Standards for Astronomical Catalogues: Units, CDS Strasbourg
      • 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
      • 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 interface ValueInfo
        Returns:
        the UCD, or null if none is known
        See Also:
        Unified Column Descriptor scheme, UCD
      • setUtype

        public void setUtype​(java.lang.String utype)
        Sets the Utype string applying to values described by this object.
        Parameters:
        utype - the Utype, or null if none is known
      • 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.
        Specified by:
        getUtype in interface ValueInfo
        Returns:
        the Utype, or null if none is known
      • setXtype

        public void setXtype​(java.lang.String xtype)
        Sets the Xtype string applying to values described by this object.
        Parameters:
        xtype - the Xtype, or null if none is known
      • getXtype

        public java.lang.String getXtype()
        Description copied from interface: ValueInfo
        Returns the Xtype string applying to the values described by this object. The Xtype string is the 'extended type' information characterising the data type beyond the primitive data type. It is used within IVOA standards, and a number of standard values are defined within the DALI standard.
        Specified by:
        getXtype in interface ValueInfo
        Returns:
        the Xtype, or null if none is known
      • 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
      • 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 interface ValueInfo
        Returns:
        a textual description, or the empty string "" if there is nothing to be said
      • 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 interface ValueInfo
        Returns:
        the java class
      • 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
      • 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 as
             getContentClass().getComponentType()!=null
         
        Specified by:
        isArray in interface ValueInfo
        Returns:
        true iff the values described by this object are java arrays
      • getShape

        public int[] getShape()
        Description copied from interface: ValueInfo
        Returns the shape associated with array value types. If the class returned by ValueInfo.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).

        Specified by:
        getShape in interface ValueInfo
        Returns:
        the shape of the array value
      • 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
      • 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 by ValueInfo.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 interface ValueInfo
        Returns:
        notional size of each element an array of values described by this info
      • setElementSize

        public void setElementSize​(int size)
        Sets the element size of values described by this object.
        Parameters:
        size - the element size
      • 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 interface ValueInfo
        Returns:
        false if values are guaranteed non-null
      • 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
      • 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 interface ValueInfo
        Returns:
        array of domain mappers for the values described by this info
      • setDomainMappers

        public void setDomainMappers​(DomainMapper[] domainMappers)
        Sets the domain mappers known for this object.
        Parameters:
        domainMappers - new domain mapper array
      • getAuxData

        public java.util.List<DescribedValue> getAuxData()
        Returns a list of auxiliary metadata objects pertaining to this column. The returned value may, if mutable, be modified to change the aux data of this object.
        Specified by:
        getAuxData in interface ValueInfo
        Returns:
        a List of DescribedValue items
      • setAuxData

        public void setAuxData​(java.util.List<DescribedValue> auxData)
        Sets the list of auxiliary metadata items for this column.
        Parameters:
        auxData - a list of DescribedValue objects
      • 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 object
        vi2 - the other ValueInfo object
        Returns:
        a generalised ValueInfo object
      • 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 interface ValueInfo
        Parameters:
        value - the value to represent
        maxLength - the maximum number of characters in the returned string
      • 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
      • 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)
      • 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 of formatShape(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[])
      • 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 interface ValueInfo
        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)
      • 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 class java.lang.Object
        Returns:
        a string representation of this object