¿No os ha pasado nunca que encontráis un artículo tan bueno que decís "éste me lo guardo"? ¿Y qué ocurre cuando lo que os ha gustado tanto es un comentario?
You can find an overview of a lot design patterns in Wikipedia . It also mentions which patterns are mentioned by GoF. I'll sum them up here and try to assign as much as possible pattern implementations found in both the Java SE and Java EE API's.
Recognizeable by creational methods returning an abstract/interface type
- java.lang.management.ManagementFactory (all getXXX() methods)
Recognizeable by creational methods returning the instance itself
- java.lang.StringBuilder#append() (unsynchronized)
- java.lang.StringBuffer#append() (synchronized)
- java.nio.ByteBuffer#put() (also on CharBuffer , ShortBuffer , IntBuffer , LongBuffer , FloatBuffer and DoubleBuffer )
- All implementations of java.lang.Appendable
Recognizeable by creational methods returning a concrete type
- java.lang.Object#toString() (overrideable in all subclasses)
- java.lang.Integer#valueOf(String) (also on Boolean , Byte , Character , Short , Long , Float and Double )
- java.lang.reflect.Array#newInstance() ,%20int%29
Recognizeable by creational methods returning a _different_ instance of itself with the same properties
Recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own/another abstract/interface type which decorates/overrides the given instance
- java.io.InputStreamReader(InputStream) (returns a Reader)
- java.io.OutputStreamWriter(OutputStream) (returns a Writer)
- javax.xml.bind.annotation.adapters.XmlAdapter#marshal() and #unmarshal()
Recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own abstract/interface type which delegates/uses the given instance
Recognizeable by behavioral methods taking an instance of same abstract/interface type
Recognizeable by creational methods taking an instance of same abstract/interface type
- All subclasses of java.io.InputStream , OutputStream , Reader and Writer have a constructor taking an instance of same type.
- Almost all implementations of java.util.List , Set and Map have a constructor taking an instance of same type.
- java.util.Collections , the checkedXXX() ,%20java.lang.Class%29, synchronizedXXX() and unmodifiableXXX() methods.
- javax.servlet.http.HttpServletRequestWrapper and HttpServletResponseWrapper
Recognizeable by behavioral methods which internally uses instances of different independent abstract/interface types
Recognizeable by creational methods returning a cached instance, a bit the "multiton" idea
Recognizeable by creational methods which returns an implementation of given abstract/interface type which in turn delegates/uses a different implementation of given abstract/interface type
The Wikipedia example is IMHO a bit poor, lazy loading has actually completely nothing to do with the proxy pattern at all
Recognizeable by behavioral methods which (indirectly) invokes the same method in another implementation of same abstract/interface type in a queue
Recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been encapsulated by the command implementation during its creation
Recognizeable by behavioral methods returning a structurally different instance/type of the given instance/type; note that parsing/formatting is not part of the pattern, determining the pattern and how to apply it is
Recognizeable by behavioral methods sequentially returning instances of a different type from a queue
Recognizeable by behavioral methods taking an instance of different abstract/interface type (usually using the command pattern) which delegates/uses the given instance
Recognizeable by behavioral methods which internally changes the state of the whole instance
Recognizeable by behavioral methods which invokes a method on an instance of another abstract/interface type, depending on own state
Recognizeable by behavioral methods which changes its behaviour depending on the instance's state which can be controlled externally
Recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been passed-in as method argument into the strategy implementation
- java.util.Comparator#compare() , executed by under each Collections#sort().
- javax.servlet.http.HttpServlet , the service() and all doXXX() methods take HttpServletRequest and HttpServletResponse and the implementor has to process them (and not to get hold of them as instance variables!).
Recognizeable by behavioral methods which already have a "default" behaviour definied by an abstract type
- All non-abstract methods of java.io.InputStream , java.io.OutputStream , java.io.Reader and java.io.Writer .
- All non-abstract methods of java.util.AbstractList , java.util.AbstractSet and java.util.AbstractMap .
- javax.servlet.http.HttpServlet , all the doXXX() methods by default sends a HTTP 405 "Method Not Allowed" error to the response. You're free to implement none or any of them.
Recognizeable by two different abstract/interface types which has methods definied which takes each the other abstract/interface type; the one actually calls the method of the other and the other executes the desired strategy on it