Class Data

java.lang.Object
com.google.api.client.util.Data
public class Data extends Object
Utilities for working with key/value data based on the Key annotation.
Since:
1.4

  • Field Details

    • NULL_BOOLEAN

      public static final Boolean NULL_BOOLEAN
      The single instance of the magic null object for a Boolean.

    • NULL_STRING

      public static final String NULL_STRING
      The single instance of the magic null object for a String.

    • NULL_CHARACTER

      public static final Character NULL_CHARACTER
      The single instance of the magic null object for a Character.

    • NULL_BYTE

      public static final Byte NULL_BYTE
      The single instance of the magic null object for a Byte.

    • NULL_SHORT

      public static final Short NULL_SHORT
      The single instance of the magic null object for a Short.

    • NULL_INTEGER

      public static final Integer NULL_INTEGER
      The single instance of the magic null object for a Integer.

    • NULL_FLOAT

      public static final Float NULL_FLOAT
      The single instance of the magic null object for a Float.

    • NULL_LONG

      public static final Long NULL_LONG
      The single instance of the magic null object for a Long.

    • NULL_DOUBLE

      public static final Double NULL_DOUBLE
      The single instance of the magic null object for a Double.

    • NULL_BIG_INTEGER

      public static final BigInteger NULL_BIG_INTEGER
      The single instance of the magic null object for a BigInteger.

    • NULL_BIG_DECIMAL

      public static final BigDecimal NULL_BIG_DECIMAL
      The single instance of the magic null object for a BigDecimal.

    • NULL_DATE_TIME

      public static final DateTime NULL_DATE_TIME
      The single instance of the magic null object for a DateTime.

    • NULL_CACHE

      private static final ConcurrentHashMap<Class<?>,Object> NULL_CACHE
      Cache of the magic null object for the given Java class.

  • Constructor Details

    • Data

      public Data()

  • Method Details

    • nullOf

      public static <T> T nullOf(Class<T> objClass)
      Returns the single instance of the magic object that represents the "null" value for the given Java class (including array or enum).
      Parameters:
      objClass - class of the object needed
      Returns:
      magic object instance that represents the "null" value (not Java null)
      Throws:
      IllegalArgumentException - if unable to create a new instance

    • createNullInstance

      private static Object createNullInstance(Class<?> objClass)

    • isNull

      public static boolean isNull(Object object)
      Returns whether the given object is the magic object that represents the null value of its class.
      Parameters:
      object - object or null
      Returns:
      whether it is the magic null value or false for null input

    • mapOf

      public static Map<String,Object> mapOf(Object data)
      Returns the map to use for the given data that is treated as a map from string key to some value.

      If the input is null, it returns an empty map. If the input is a map, it simply returns the input. Otherwise, it will create a map view using reflection that is backed by the object, so that any changes to the map will be reflected on the object. The map keys of that map view are based on the Key annotation, and null is not a possible map value, although the magic null instance is possible (see nullOf(Class) and isNull(Object)). Iteration order of the data keys is based on the sorted (ascending) key names of the declared fields. Note that since the map view is backed by the object, and that the object may change, many methods in the map view must recompute the field values using reflection, for example Map.size() must check the number of non-null fields.

      Parameters:
      data - any key value data, represented by an object or a map, or null
      Returns:
      key/value map to use

    • clone

      public static <T> T clone(T data)
      Returns a deep clone of the given key/value data, such that the result is a completely independent copy.

      This should not be used directly in the implementation of Object.clone(). Instead use deepCopy(Object, Object) for that purpose.

      Final fields cannot be changed and therefore their value won't be copied.

      Parameters:
      data - key/value data object or map to clone or null for a null return value
      Returns:
      deep clone or null for null input

    • deepCopy

      public static void deepCopy(Object src, Object dest)
      Makes a deep copy of the given source object into the destination object that is assumed to be constructed using Object.clone().

      Example usage of this method in Object.clone(): 

      @Override
public MyObject clone() {
try {
@SuppressWarnings("unchecked")
MyObject result = (MyObject) super.clone();
Data.deepCopy(this, result);
return result;
} catch (CloneNotSupportedException e) {
throw new IllegalStateException(e);
}
}

      Final fields cannot be changed and therefore their value won't be copied.

      Parameters:
      src - source object
      dest - destination object of identical type as source object, and any contained arrays must be the same length

    • isPrimitive

      public static boolean isPrimitive(Type type)
      Returns whether the given type is one of the supported primitive classes like number and date/time, or is a wildcard of one.

      A primitive class is any class for whom Class.isPrimitive() is true, as well as any classes of type: Character, String, Integer, Long, Short, Byte, Float, Double, BigInteger, BigDecimal, Boolean, and DateTime.

      Parameters:
      type - type or null for false result
      Returns:
      whether it is a primitive

    • isValueOfPrimitiveType

      public static boolean isValueOfPrimitiveType(Object fieldValue)
      Returns whether to given value is null or its class is primitive as defined by isPrimitive(Type).

    • parsePrimitiveValue

      public static Object parsePrimitiveValue(Type type, String stringValue)
      Parses the given string value based on the given primitive type.

      Types are parsed as follows:

      Note that this may not be the right behavior for some use cases.

      Parameters:
      type - primitive type or null to parse as a string
      stringValue - string value to parse or null for null result
      Returns:
      parsed object or null for null input
      Throws:
      IllegalArgumentException - if the given class is not a primitive class

    • newCollectionInstance

      public static Collection<Object> newCollectionInstance(Type type)
      Returns a new collection instance for the given type.

      Creates a new collection instance specified for the first input collection class that matches as follows:

      Parameters:
      type - type or null for ArrayList.
      Returns:
      new collection instance
      Throws:
      ClassCastException - if result is does not extend Collection

    • newMapInstance

      public static Map<String,Object> newMapInstance(Class<?> mapClass)
      Returns a new instance of a map based on the given field class.

      Creates a new map instance specified for the first input map class that matches as follows:

      Parameters:
      mapClass - field class
      Throws:
      ClassCastException - if result is does not extend Map

    • resolveWildcardTypeOrTypeVariable

      public static Type resolveWildcardTypeOrTypeVariable(List<Type> context, Type type)
      Aggressively resolves the given type in such a way that the resolved type is not a wildcard type or a type variable, returning Object.class if the type variable cannot be resolved.
      Parameters:
      context - context list, ordering from least specific to most specific type context, for example container class and then its field
      type - type or null for null result
      Returns:
      resolved type (which may be class, parameterized type, or generic array type, but not wildcard type or type variable) or null for null input