Package io.permazen.encoding

Class PrimitiveEncoding<T>

java.lang.Object
io.permazen.encoding.AbstractEncoding<T>
io.permazen.encoding.PrimitiveEncoding<T>
All Implemented Interfaces:
Encoding<T>, NaturalSortAware, Serializable, Comparator<T>
Direct Known Subclasses:
BooleanEncoding, CharacterEncoding, NumberEncoding, VoidEncoding
public abstract class PrimitiveEncoding<T> extends AbstractEncoding<T>
Support superclass for built-in primitive type encodings.
See Also:

  • Constructor Details

    • PrimitiveEncoding

      protected PrimitiveEncoding(EncodingId encodingId, Primitive<T> primitive)

    • PrimitiveEncoding

      protected PrimitiveEncoding(Primitive<T> primitive)

  • Method Details

    • fromString

      public T fromString(String string)
      Description copied from interface: Encoding
      Parse a non-null value previously encoded by toString(T).
      Parameters:
      string - non-null value previously encoded as a String by toString(T)
      Returns:
      actual value

    • toString

      public String toString(T value)
      Description copied from interface: Encoding
      Encode a non-null value as a String for later decoding by fromString().

      Each of the characters in the returned String, when decoded as 32-bit Unicode codepoints, must contain only valid XML characters (see XMLUtil.isValidChar(int)).

      Parameters:
      value - actual value, never null
      Returns:
      string encoding of value acceptable to fromString()
      See Also:

    • validate

      public T validate(Object obj)
      Description copied from interface: Encoding
      Verify the given object is a valid instance of this Encoding's Java type and cast it to that type.

      Note that this method must throw IllegalArgumentException, not ClassCastException or NullPointerException, if obj does not have the correct type, or is an unsupported value - including null if null is not supported.

      This method is allowed to perform widening conversions of the object that lose no information, e.g., from Integer to Long.

      The implementation in Encoding first verifies the value is not null if this instance does not allow null values, and then attempts to cast the value using this instance's raw Java type. Subclasses should override this method to implement any other restrictions.

      Parameters:
      obj - object to validate
      Returns:
      obj cast to this encoding's type

    • compare

      public int compare(T value1, T value2)
      Description copied from interface: Encoding
      Order two values.

      This method must provide a total ordering of all supported Java values that is consistent with the database ordering, i.e., the unsigned lexicographical ordering of the corresponding byte[] encoded values.

      If null is a supported Java value, then the this method must accept null parameters without throwing an exception (note, this is a stronger requirement than the Comparator interface normally requires).

      Note: by convention, null values usually sort last.

    • supportsNull

      public boolean supportsNull()
      Description copied from interface: Encoding
      Determine whether this encoding supports null values.
      Returns:
      true if null is a valid value, otherwise false

    • sortsNaturally

      public boolean sortsNaturally()
      Description copied from interface: NaturalSortAware
      Determine if this instance sorts Java instances naturally.

      This method should return true only if all of the following are true:

      • This class also implements Comparator for some Java type T.
      • Type T has a natural ordering (i.e., T itself implements Comparable).
      • The ordering implied by this class's compare() method is identical to T's natural ordering.
      Returns:
      true if this instance orders Java values in their natural order

    • convert

      public <S> T convert(Encoding<S> type, S value)
      Description copied from interface: Encoding
      Attempt to convert a value from the given Encoding into a value of this Encoding.

      For a non-null value, the implementation in Encoding first checks whether the value is already a valid value for this encoding; if so, the value is returned. Otherwise, it invokes encoding.toString(value) to convert value into a String, and then attempts to parse that string via this.fromString(); if the parse fails, an IllegalArgumentException is thrown. Note this means that any value will convert successfully to a String, as long as it doesn't contain an invalid escape sequence (see StringEncoding.toString(java.lang.String)).

      If value is null, the implementation in Encoding returns null, unless this encoding does not support null values, in which case an IllegalArgumentException is thrown.

      Permazen's built-in encodings include the following conversions:

      • Non-boolean Primitive types:
        • Convert from other non-boolean primitive types as if by the corresponding Java cast
        • Convert from boolean by converting to zero (if false) or one (if true)
      • Boolean: converts from other primitive types as if by value != 0
      • A char[] array and a String are convertible to each other
      • A char and a String of length one are convertible to each other (other Strings are not)
      • Arrays: converted by converting each array element individually (if possible)
      Type Parameters:
      S - source encoding
      Parameters:
      type - the Encoding of value
      value - the value to convert
      Returns:
      value converted to this instance's type

    • convertNumber

      protected abstract T convertNumber(Number value)

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class AbstractEncoding<T>

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in interface Comparator<T>
      Overrides:
      equals in class AbstractEncoding<T>