類圖生成方法###
以一個裝飾器模式實現數學運算的例子為例。
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安裝 Intellj Ultimate ， lience server: http://xdouble.cn:8888/
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在類上右鍵點擊 class diagram :
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在得到的類的框框上 “雙指單擊”或右鍵 ， 選擇 show Implementations :
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得到的實現類列表上， Ctrl + A 全選
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Enter 得到類圖結果，上面有 導出圖片功能。
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可以查看接口及實現類的覆寫方法
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調整布局
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添加額外的類
如果發現還有點單獨的接口有關聯但是不在上述繼承體系里, 可以添加額外的 class diagram 並按上如法炮制。 -
導出圖片保存
裝飾器代碼###
Function.java 函數接口, sources 是被裝飾的內層函數運算。
package zzz.study.patterns.decorator.func;
public abstract class Function {
protected Function[] sources;
public Function(Function[] sources) {
this.sources = sources;
}
public Function(Function f) {
this(new Function[] {f});
}
public abstract double f(double t);
public String toString() {
String name = this.getClass().toString();
StringBuffer buf = new StringBuffer(name);
if (sources.length > 0) {
buf.append('(');
for (int i=0; i < sources.length; i++) {
if (i > 0)
buf.append(",");
buf.append(sources[i]);
}
buf.append(')');
}
return buf.toString();
}
}
Constant.java ：常量函數
package zzz.study.patterns.decorator.func;
public class Constant extends Function {
private double constant;
public Constant() {
super(new Function[] {});
}
public Constant(double constant) {
super(new Function[]{});
this.constant = constant;
}
public double f(double t) {
return constant;
}
public String toString() {
return Double.toString(constant);
}
}
T.java : 線性函數
package zzz.study.patterns.decorator.func;
public class T extends Function {
public T() {
super(new Function[] {});
}
public double f(double t) {
return t;
}
public String toString() {
return "t";
}
}
Square.java ：平方函數
package zzz.study.patterns.decorator.func;
public class Square extends Function {
public Square() {
super(new Function[] {});
}
public Square(Function f) {
super(new Function[] {f});
}
public double f(double t) {
return Math.pow(sources[0].f(t),2);
}
public String toString() {
StringBuffer buf = new StringBuffer("");
if (sources.length > 0) {
buf.append('(');
buf.append(sources[0]);
buf.append('^');
buf.append(2);
buf.append(')');
}
return buf.toString();
}
}
ExpDouble.java ：指數函數
package zzz.study.patterns.decorator.func;
public class ExpDouble extends Function {
private double expDouble; // 指數的底數
public ExpDouble() {
super(new Function[] {});
}
public ExpDouble(double expDouble, Function f) {
super(new Function[] {f});
this.expDouble = expDouble;
}
public double f(double t) {
return Math.pow(expDouble, sources[0].f(t));
}
public String toString() {
StringBuffer buf = new StringBuffer("");
if (sources.length > 0) {
buf.append('(');
buf.append('(');
buf.append(expDouble);
buf.append(')');
buf.append('^');
buf.append(sources[0]);
buf.append(')');
}
return buf.toString();
}
}
Pow.java ：冪函數
package zzz.study.patterns.decorator.func;
public class Pow extends Function {
private double pow; // 冪函數的指數
public Pow() {
super(new Function[] {});
}
public Pow(Function f, double pow) {
super(new Function[] {f});
this.pow = pow;
}
public double f(double t) {
return Math.pow(sources[0].f(t), pow);
}
public String toString() {
StringBuffer buf = new StringBuffer("");
if (sources.length > 0) {
buf.append('(');
buf.append(sources[0]);
buf.append('^');
buf.append('(');
buf.append(pow);
buf.append(')');
buf.append(')');
}
return buf.toString();
}
}
Arithmetic.java ：四則運算
package zzz.study.patterns.decorator.func;
public class Arithmetic extends Function {
protected char op;
public Arithmetic(char op, Function f1, Function f2) {
super(new Function[] {f1, f2});
this.op = op;
}
public double f(double t) {
switch(op) {
case '+':
return sources[0].f(t) + sources[1].f(t);
case '-':
return sources[0].f(t) - sources[1].f(t);
case '*':
return sources[0].f(t) * sources[1].f(t);
case '/':
return sources[0].f(t) / sources[1].f(t);
default:
return 0;
}
}
public String toString() {
StringBuffer buf = new StringBuffer("");
if (sources.length > 0) {
buf.append('(');
buf.append(sources[0]);
buf.append(Character.toString(op));
buf.append(sources[1]);
buf.append(')');
}
return buf.toString();
}
}
Sin.java , Cos.java 請讀者自行完成。
測試：
package zzz.study.patterns.decorator;
import zzz.study.patterns.decorator.func.Arithmetic;
import zzz.study.patterns.decorator.func.Cos;
import zzz.study.patterns.decorator.func.Function;
import zzz.study.patterns.decorator.func.Sin;
import zzz.study.patterns.decorator.func.Square;
import zzz.study.patterns.decorator.func.T;
public class ShowFunction {
public static void main(String[] args) {
Function complexFunc = new Arithmetic('+', new Square(new Sin(new T())), new Square(new Cos(new T())));
System.out.println(complexFunc + " = " + complexFunc.f(100.0));
}
}
在 《Java函數接口實現函數組合及裝飾器模式》 一文中，使用 Function 接口有更簡潔的裝飾器模式實現。