Class AbstractDecorator<D>

  • All Implemented Interfaces:
    Serializable, Wrapper, Wrapper
    Direct Known Subclasses:
    DecoratingDataStore

    public class AbstractDecorator<D>
    extends Object
    implements Wrapper, Serializable
    Generic delegating base class. Provides the following features:
    • null check for the delegate object
    • direct forwarding of equals(Object), hashCode() and toString() to the delegate
    • implements the Wrapper interface for programmatic extraction
    See Also:
    Serialized Form
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected D delegate  
    • Constructor Summary

      Constructors 
      Constructor Description
      AbstractDecorator​(D delegate)  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean equals​(Object obj)  
      int hashCode()  
      boolean isWrapperFor​(Class<?> iface)
      Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does.
      String toString()  
      <T> T unwrap​(Class<T> iface)
      Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy.
      • Methods inherited from class Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait
    • Field Detail

      • delegate

        protected D delegate
    • Constructor Detail

      • AbstractDecorator

        public AbstractDecorator​(D delegate)
    • Method Detail

      • isWrapperFor

        public boolean isWrapperFor​(Class<?> iface)
        Description copied from interface: Wrapper
        Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does. Returns false otherwise. If this implements the interface then return true, else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped object. If this does not implement the interface and is not a wrapper, return false. This method should be implemented as a low-cost operation compared to unwrap so that callers can use this method to avoid expensive unwrap calls that may fail. If this method returns true then calling unwrap with the same argument should succeed.
        Specified by:
        isWrapperFor in interface Wrapper
        Specified by:
        isWrapperFor in interface Wrapper
        Parameters:
        iface - a Class defining an interface.
        Returns:
        true if this implements the interface or directly or indirectly wraps an object that does.
      • unwrap

        public <T> T unwrap​(Class<T> iface)
                     throws IllegalArgumentException
        Description copied from interface: Wrapper
        Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy.

        If the receiver implements the interface then the result is the receiver or a proxy for the receiver. If the receiver is a wrapper and the wrapped object implements the interface then the result is the wrapped object or a proxy for the wrapped object. Otherwise return the the result of calling unwrap recursively on the wrapped object or a proxy for that result. If the receiver is not a wrapper and does not implement the interface, then an IllegalArgumentException is thrown.

        Specified by:
        unwrap in interface Wrapper
        Specified by:
        unwrap in interface Wrapper
        Parameters:
        iface - A Class defining an interface that the result must implement.
        Returns:
        an object that implements the interface. May be a proxy for the actual implementing object.
        Throws:
        IllegalArgumentException - If no object found that implements the interface
      • equals

        public boolean equals​(Object obj)
        Overrides:
        equals in class Object
      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object
      • toString

        public String toString()
        Overrides:
        toString in class Object