Class ColumnInfo

java.lang.Object
uk.ac.starlink.table.DefaultValueInfo
uk.ac.starlink.table.ColumnInfo
All Implemented Interfaces:
ValueInfo
public class ColumnInfo extends DefaultValueInfo
Contains information about a table column. This really does the same thing as its superclass, DefaultValueInfo, but for historical reasons it contains some additional methods for access to the auxiliary metadata items. In earlier versions of the library, columns were allowed to store auxiliary metadata and non-column items (like table parameters) were not, but now they have the same capabilities.
Author:
Mark Taylor (Starlink)

  • Constructor Details

    • ColumnInfo

      public ColumnInfo(String name)
      Constructs a ColumnInfo object.
      Parameters:
      name - the name of the column

    • ColumnInfo

      public ColumnInfo(ValueInfo base)
      Constructs a new ColumnInfo based on a ValueInfo object. All attributes are copied from the template to the new object.
      Parameters:
      base - the template ValueInfo

    • ColumnInfo

      public ColumnInfo(String name, Class<?> contentClass, String description)
      Constructs a new ColumnInfo 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

  • Method Details

    • getAuxDatum

      public DescribedValue getAuxDatum(ValueInfo vinfo)
      Gets an item of auxiliary metadata from its specification. Currently this just calls getAuxDatumByName(vinfo.getName()), but may be revised in future to match on other attributes.
      Parameters:
      vinfo - the data item to match
      Returns:
      a DescribedValue object representing the auxiliary metadata item matching vinfo for this column, or null if none exists

    • getAuxDatumValue

      public <T> T getAuxDatumValue(ValueInfo vinfo, Class<T> clazz)
      Gets the value of an item of auxiliary metadata using its specification, requiring a particular return type. This convenience method works like getAuxDatum(ValueInfo) but returns a non-null value only if the named item exists and if its value is an instance of the given type clazz.
      Parameters:
      vinfo - the data item to match
      clazz - required return type
      Returns:
      value of the auxiliary metadata item matching vinfo for this column if it exists and is an instance of clazz or one of its subtypes, otherwise null

    • getAuxDatumValueByName

      public <T> T getAuxDatumValueByName(String name, Class<T> clazz)
      Gets the value of an item of auxiliary metadata by its name, requiring a particular return type. This convenience method works like ValueInfo.getAuxDatumByName(String), but returns a non-null value only if the named item exists, and if its value is an instance of the given type clazz.
      Parameters:
      name - the name of an auxiliary metadata item
      clazz - required return type
      Returns:
      value of the auxiliary metadata item matching vinfo for this column if it exists and is an instance of clazz or one of its subtypes, otherwise null

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