uk.ac.starlink.table

## Class URLValueInfo

- java.lang.Object
- - uk.ac.starlink.table.URLValueInfo

- All Implemented Interfaces:
    ValueInfo

      public class URLValueInfo
      extends java.lang.Object
      implements ValueInfo

  ValueInfo for URL values.
  Since:
    16 Sep 2004

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `URLValueInfo(java.lang.String name, java.lang.String description)` Constructs a new URLValueInfo.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.lang.String` | `formatValue(java.lang.Object value, int maxLength)` Returns a string representation of a given value described by this `ValueInfo`.
    `java.util.List<DescribedValue>` | `getAuxData()` Returns a list of auxiliary metadata objects pertaining to this info.
    `javax.swing.table.TableCellRenderer` | `getCellRenderer()`
    `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 Content 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`.
    `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, toString, wait, wait, wait`

    - ### Methods inherited from interface uk.ac.starlink.table.ValueInfo

      `getAuxDatumByName, setAuxDatum`

- - ### Constructor Detail

    - #### URLValueInfo

          public URLValueInfo(java.lang.String name,
                              java.lang.String description)

      Constructs a new URLValueInfo.
      Parameters:
        `name` - info name
        `description` - info description

  - ### Method Detail

    - #### 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

    - #### 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

    - #### 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 correspond to the VOUnit standard.
      Specified by:
        `getUnitString` in interface `ValueInfo`
      Returns:
        a string giving the units, or `null` if units are unknown

    - #### getUCD

          public java.lang.String getUCD()

      Description copied from interface: `ValueInfo`
      Returns the Unified Content 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:
        UCD, `UCD`

    - #### 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

    - #### 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

    - #### 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

    - #### 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

    - #### 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

    - #### 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`

    - #### 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

    - #### getAuxData

          public java.util.List<DescribedValue> getAuxData()

      Description copied from interface: `ValueInfo`
      Returns a list of auxiliary metadata objects pertaining to this info. This is intended as a repository for metadata which is not otherwise made available in this interface.
      Specified by:
        `getAuxData` in interface `ValueInfo`
      Returns:
        a List of `DescribedValue` items

    - #### 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

    - #### 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)

    - #### getCellRenderer

          public javax.swing.table.TableCellRenderer getCellRenderer()