carfield.com.hk

Adapter.java

2001-12-26T16:00:00Z

//: c07:Adapter.java
// Variations on the Adapter pattern.
import com.bruceeckel.test.*;

class WhatIHave {
  public void g() {}
  public void h() {}
}

interface WhatIWant {
  void f();
}

class ProxyAdapter implements WhatIWant {
  WhatIHave whatIHave;
  public ProxyAdapter(WhatIHave wih) {
    whatIHave = wih;
  }
  public void f() {
    // Implement behavior using 
    // methods in WhatIHave:
    whatIHave.g();
    whatIHave.h();
  }
}
  
class WhatIUse {
  public void op(WhatIWant wiw) {
    wiw.f();
  }
}

// Approach 2: build adapter use into op():
class WhatIUse2 extends WhatIUse {
  public void op(WhatIHave wih) {
    new ProxyAdapter(wih).f();
  }
}

// Approach 3: build adapter into WhatIHave:
class WhatIHave2 extends WhatIHave 
implements WhatIWant {
  public void f() {
    g();
    h();
  }
}

// Approach 4: use an inner class:
class WhatIHave3 extends WhatIHave {
  private class InnerAdapter implements WhatIWant{
    public void f() {
      g();
      h();
    }
  }
  public WhatIWant whatIWant() { 
    return new InnerAdapter(); 
  }
}

public class Adapter extends UnitTest {
  WhatIUse whatIUse = new WhatIUse();
  WhatIHave whatIHave = new WhatIHave();
  WhatIWant adapt= new ProxyAdapter(whatIHave);
  WhatIUse2 whatIUse2 = new WhatIUse2();
  WhatIHave2 whatIHave2 = new WhatIHave2();
  WhatIHave3 whatIHave3 = new WhatIHave3();
  public void test() {
    whatIUse.op(adapt);
    // Approach 2:
    whatIUse2.op(whatIHave);
    // Approach 3:
    whatIUse.op(whatIHave2);
    // Approach 4:
    whatIUse.op(whatIHave3.whatIWant());
  }
  public static void main(String args[]) {
    new Adapter().test();
  }
} ///:~

Facade.java

2001-12-26T16:00:00Z

makefile

2001-12-26T16:00:00Z

# From Thinking in Patterns (with Java) by Bruce Eckel
# At http://www.BruceEckel.com
# (c)2001 Bruce Eckel 
# Copyright notice in Copyright.txt
# Automatically-generated MAKEFILE 
# For examples in directory .\c07
# using the JDK 1.3 compiler
# Invoke with: make

HOME := ../

ifndef MAKECMDGOALS
MAKECMDGOALS := javac
endif

# Command.com is too weak to build this under Windows NT/2000:
ifeq ($(OS),Windows_NT)
COMSPEC=$(SYSTEMROOT)\system32\cmd.exe
endif

ifneq ($(MAKECMDGOALS),clean)
include $(HOME)/$(MAKECMDGOALS).mac
endif

.SUFFIXES : .class .java
.java.class :
	$(JVC) $(JVCFLAGS) $<

javac: \
	Adapter.class \
	Facade.class

jikes: \
	Adapter.class \
	Facade.class

clean:
ifeq ($(notdir $(SHELL)),COMMAND.COM)
	del *.class
else
	rm -f *.class
endif


Adapter.class: Adapter.java 
	$(JVC) $(JVCFLAGS) $<
	java com.bruceeckel.test.RunUnitTests Adapter
Facade.class: Facade.java 
	$(JVC) $(JVCFLAGS) $<
	java com.bruceeckel.test.RunUnitTests Facade