fr.umlv.jmmf.matcher
Class PatternMatcher

java.lang.Object
  |
  +--fr.umlv.jmmf.matcher.PatternMatcher

public class PatternMatcher

extends java.lang.Object

This class ease the use of multi-polymorphism. A simple way to use it consist in subclassing the PatternMatcher class. An example on a tree recursive type :

public class Test extends PatternMatcher
{
  public interface Tree {}
  public static class Leaf implements Tree {
    Leaf(int value) {
      this.value=value;
    }
    int value;
  }
  public static class Node implements Tree {
    Node(Tree left,Tree right) {
      this.left=left; this.right=right;
    }
    Tree left,right;
  }

  public int sum(Node node)
  { return sum(left)+sum(right); }
  public int sum(Leaf leaf)
  { return value; }

  public int sum(Tree tree)
  { return ((Integer)match("sum",tree)).intValue(); }

  public static void main(String[] args) {
    Tree tree=new Node(new Node(new Leaf(1),new Leaf(3)),new Leaf(7));
    System.out.println("sum "+new Test().sum(tree));
  }
}

Version:

0.8.2

Author:

Remi Forax

Constructor Summary

PatternMatcher()
create a pattern matcher component.

PatternMatcher(java.lang.Object bean)
create a pattern matcher component on a bean object.

PatternMatcher(java.lang.Object bean, MultiFactory factory)
create a pattern matcher component on a bean object.

Method Summary

java.lang.Object	match(java.lang.String name, java.lang.Object arg) lookup the best method in the multi-method named name and invoke it.
java.lang.Object	match(java.lang.String name, java.lang.Object[] args) lookup the best method in the multi-method named name and invoke it.
java.lang.Object	match(java.lang.String name, java.lang.Object[] args, java.lang.Class[] classes) lookup the best method in the multi-method named name and invoke it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PatternMatcher

public PatternMatcher()

create a pattern matcher component. Find all multi-methods in this component and store them.

PatternMatcher

public PatternMatcher(java.lang.Object bean)

create a pattern matcher component on a bean object. Find all multi-methods in the bean component and store them.

PatternMatcher

public PatternMatcher(java.lang.Object bean,
                      MultiFactory factory)

create a pattern matcher component on a bean object. Find all multi-methods in the bean component and store them.

Method Detail

match

public java.lang.Object match(java.lang.String name,
                              java.lang.Object arg)

lookup the best method in the multi-method named name and invoke it.

Parameters:

name - name of the multi-method.

arg - first parameter of the multi-method.

Returns:

the result of a call of the best method of the multi-method. if the type of the result is a primitive type, the result is wrapped in the corresponding object (int -> Integer, etc...).

Throws:

NoMatchingMethodException - there is no method that match the parameter arguments.

MultipleMatchingMethodsException - there is no method that match the parameter arguments.

MatchingMethodInvocationException - throws by the target method invoked.

IllegalStateException - is method find isn't accessible, due to an internal error.

See Also:

match(String, Object[], Class[])

match

public java.lang.Object match(java.lang.String name,
                              java.lang.Object[] args)

lookup the best method in the multi-method named name and invoke it.

Parameters:

name - name of the multi-method.

args - parameters of the multi-method.

Returns:

the result of a call of the best method of the multi-method. if the type of the result is a primitive type, the result is wrapped in the corresponding object (int -> Integer, etc...).

Throws:

NoMatchingMethodException - there is no method that match the parameter arguments.

MultipleMatchingMethodsException - there is no method that match the parameter arguments.

MatchingMethodInvocationException - throws by the target method invoked.

IllegalStateException - is method find isn't accessible, due to an internal error.

See Also:

match(String, Object[], Class[])

match

public java.lang.Object match(java.lang.String name,
                              java.lang.Object[] args,
                              java.lang.Class[] classes)

lookup the best method in the multi-method named name and invoke it.

Parameters:

name - name of the multi-method.

args - parameters of the multi-method.

classes - type of the parameter.

Returns:

the result of a call of the best method of the multi-method. if the type of the result is a primitive type, the result is wrapped in the corresponding object (int -> Integer, etc...).

Throws:

NoMatchingMethodException - there is no method that match the parameter arguments.

MultipleMatchingMethodsException - there is no method that match the parameter arguments.

MatchingMethodInvocationException - throws by the target method invoked.

IllegalStateException - is method find isn't accessible, due to an internal error.