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這篇文章給大家介紹怎么在java項(xiàng)目中實(shí)現(xiàn)一個(gè)Composite組合模式,內(nèi)容非常詳細(xì),感興趣的小伙伴們可以參考借鑒,希望對(duì)大家能有所幫助。
組合模式核心思想類似文件夾的概念,構(gòu)件樹(shù)形結(jié)構(gòu),樹(shù)形有葉子結(jié)點(diǎn)和文件夾結(jié)點(diǎn),文件夾結(jié)點(diǎn)可以包含葉子結(jié)點(diǎn)和文件夾結(jié)點(diǎn)
分為兩種模式
- 透明型:所有節(jié)點(diǎn)構(gòu)造全部相同,但是由于葉子結(jié)點(diǎn)沒(méi)有下層結(jié)點(diǎn),所以其有些方法為空,會(huì)不安全
- 安全型:葉子結(jié)點(diǎn)和文件架節(jié)點(diǎn)構(gòu)造不同,這樣展示的時(shí)候需要判斷節(jié)點(diǎn)屬性,不方便調(diào)用,但是由于沒(méi)有空方法,會(huì)很安全
透明型組合模式程序源代碼:
//節(jié)點(diǎn)抽象父類 /** * 透明模式就是把組合使用的方法放到抽象類中,不管葉子對(duì)象還是數(shù)值對(duì)象都有相同的結(jié)構(gòu) * 這樣做的好處就是葉子結(jié)點(diǎn)和樹(shù)枝結(jié)點(diǎn)對(duì)于外界沒(méi)有區(qū)別,他們具備完全一致的行為接口 */ public abstract class ComponentTransparent { protected String name; public ComponentTransparent(String name){ this.name = name; } //增加一個(gè)葉子構(gòu)件或者樹(shù)枝構(gòu)件 public abstract void add(ComponentTransparent componentTransparent); //刪除 public abstract void remove(ComponentTransparent componentTransparent); //獲取分支下的所有葉子構(gòu)件和樹(shù)枝構(gòu)件 public abstract void display(int depth); }
//文件架節(jié)點(diǎn)實(shí)現(xiàn)子類 import java.util.ArrayList; public class CompositeTransparent extends ComponentTransparent{ public CompositeTransparent(String name){ super(name); } //構(gòu)建容器 private ArrayList<ComponentTransparent> componentTransparentsArraylist= new ArrayList<>(); @Override public void add(ComponentTransparent componentTransparent) { this.componentTransparentsArraylist.add(componentTransparent); } @Override public void remove(ComponentTransparent componentTransparent) { this.componentTransparentsArraylist.remove(componentTransparent); } @Override public void display(int depth) { //輸出樹(shù)形結(jié)構(gòu) for (int i = 0;i<depth;++i){ System.out.print("-"); } System.out.println(this.name); //下級(jí)遍歷 for(ComponentTransparent componentTransparent:this.componentTransparentsArraylist){ componentTransparent.display(depth+1); } } }
//葉子節(jié)點(diǎn)實(shí)現(xiàn)子類 public class LeafTransparent extends ComponentTransparent{ public LeafTransparent(String name){ super(name); } @Override public void add(ComponentTransparent componentTransparent) { //空實(shí)現(xiàn),拋出"不支持請(qǐng)求"異常 throw new UnsupportedOperationException(); } @Override public void remove(ComponentTransparent componentTransparent) { throw new UnsupportedOperationException(); } @Override public void display(int depth) { //輸出樹(shù)形結(jié)構(gòu)的葉子節(jié)點(diǎn) for (int i = 0;i<depth;++i){ System.out.print("-"); } System.out.println(this.name); } }
安全型組合模式源代碼:安全型中,葉子結(jié)點(diǎn)沒(méi)有增加移除方法,方法需要自己實(shí)現(xiàn),而不會(huì)在父類中指出
//節(jié)點(diǎn)抽象父類 public abstract class ComponentSafty { protected String name; public ComponentSafty(String name){ this.name = name; } //展示 public abstract void display(int depth); }
//文件夾節(jié)點(diǎn)實(shí)現(xiàn)子類 import java.util.ArrayList; public class CompositeSafty extends ComponentSafty{ public CompositeSafty(String name){ super(name); } private ArrayList<ComponentSafty> componentSaftyArrayList = new ArrayList<>(); public void add(ComponentSafty component){ this.componentSaftyArrayList.add(component); } public void remove(ComponentSafty componentSafty){ this.componentSaftyArrayList.remove(componentSafty); } @Override public void display(int depth) { for (int i=0;i<depth;++i){ System.out.print("-"); } System.out.println(this.name); for (ComponentSafty componentSafty : componentSaftyArrayList) { componentSafty.display(depth+1); } } }
//葉子結(jié)點(diǎn)實(shí)現(xiàn)子類 public class LeafSafty extends ComponentSafty{ public LeafSafty(String name){ super(name); } @Override public void display(int depth) { for (int i=0;i<depth;++i){ System.out.print("-"); } System.out.println(this.name); } }
測(cè)試主類程序源代碼
//測(cè)試主類 public class Main { private static void transparent(){ //創(chuàng)建根節(jié)點(diǎn)以及其子節(jié)點(diǎn) ComponentTransparent root = new CompositeTransparent("root"); root.add(new LeafTransparent("Leaf A")); root.add(new LeafTransparent("Leaf B")); //創(chuàng)建第二層結(jié)點(diǎn)及其子節(jié)點(diǎn) ComponentTransparent branch = new CompositeTransparent("Composite X"); branch.add(new LeafTransparent("Leaf XA")); branch.add(new LeafTransparent("Leaf XB")); root.add(branch); //創(chuàng)建第三層節(jié)點(diǎn)及其子結(jié)點(diǎn) ComponentTransparent branch3 = new CompositeTransparent("Composite XY"); branch3.add(new LeafTransparent("Leaf XYA")); branch3.add(new LeafTransparent("Leaf XYB")); branch.add(branch3); //創(chuàng)建第二層結(jié)點(diǎn) root.add(new LeafTransparent("Leaf C")); //常見(jiàn)第二層節(jié)點(diǎn)并刪除 ComponentTransparent leaf = new LeafTransparent("Leaf D"); root.add(leaf); root.display(1); root.remove(leaf); for(int i =0;i<10;++i){ System.out.print("="); } System.out.println(); //展示 root.display(1); } private static void safty(){ //創(chuàng)建根節(jié)點(diǎn)以及其子節(jié)點(diǎn) CompositeSafty root = new CompositeSafty("root"); root.add(new LeafSafty("Leaf A")); root.add(new LeafSafty("Leaf B")); //創(chuàng)建第二層結(jié)點(diǎn)及其子節(jié)點(diǎn) CompositeSafty branch = new CompositeSafty("Composite X"); branch.add(new LeafSafty("Leaf XA")); branch.add(new LeafSafty("Leaf XB")); root.add(branch); //創(chuàng)建第三層節(jié)點(diǎn)及其子結(jié)點(diǎn) CompositeSafty branch3 = new CompositeSafty("Composite XY"); branch3.add(new LeafSafty("Leaf XYA")); branch3.add(new LeafSafty("Leaf XYB")); branch.add(branch3); //創(chuàng)建第二層結(jié)點(diǎn) root.add(new LeafSafty("Leaf C")); //常見(jiàn)第二層節(jié)點(diǎn)并刪除 LeafSafty leaf = new LeafSafty("Leaf D"); root.add(leaf); root.display(1); root.remove(leaf); for(int i =0;i<10;++i){ System.out.print("="); } System.out.println(); //展示 root.display(1); } public static void main(String[] args) { System.out.println("透明模式:"); transparent(); for(int i =0;i<10;++i){ System.out.print("="); } System.out.println(); System.out.println("安全模式:"); safty(); } }
輸出如下:
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