合成模式代码示例

package com.example.hecheng;


public interface IFile
{
	
	//返回自己的实例 
	IFile getComposite();
	
	//某个商业方法 
	void sampleOperation();
	
	//获取深度 
	int getDeep();
	
	//设置深度 
	void setDeep(
			int x );
}

</pre><p></p><p></p><pre name="code" class="html">package com.example.hecheng;



public class File implements IFile
{
	
	private String name; //文件名字 
	private int deep; //层级深度 
	
	public File(
			String name )
	{
		this.name = name;
	}
	
	//返回自己的实例 
	public IFile getComposite()
	{
		return this;
	}
	
	//某个商业方法 
	public void sampleOperation()
	{
		System.out.println( "执行了某个商业方法！" );
	}
	
	public String getName()
	{
		return name;
	}
	
	public void setName(
			String name )
	{
		this.name = name;
	}
	
	public int getDeep()
	{
		return deep;
	}
	
	public void setDeep(
			int deep )
	{
		this.deep = deep;
	}
}

package com.example.hecheng;


import java.util.Vector;

public class Folder implements IFile
{
	
	private String name; //文件名字 
	private int deep; //层级深度，根深度为0 
	private Vector<IFile> componentVector = new Vector<IFile>();
	
	public Folder(
			String name )
	{
		this.name = name;
	}
	
	//返回自己的实例 
	public IFile getComposite()
	{
		return this;
	}
	
	//某个商业方法 
	public void sampleOperation()
	{
		System.out.println( "执行了某个商业方法！" );
	}
	
	//增加一个文件或文件夹 
	public void add(
			IFile IFile )
	{
		componentVector.addElement( IFile );
		IFile.setDeep( this.deep + 1 );
	}
	
	//删除一个文件或文件夹 
	public void remove(
			IFile IFile )
	{
		componentVector.removeElement( IFile );
	}
	
	//返回直接子文件（夹）集合 
	public Vector getAllComponent()
	{
		return componentVector;
	}
	
	public String getName()
	{
		return name;
	}
	
	public void setName(
			String name )
	{
		this.name = name;
	}
	
	public int getDeep()
	{
		return deep;
	}
	
	public void setDeep(
			int deep )
	{
		this.deep = deep;
	}
}

package com.example.hecheng;


import java.util.Iterator;
import java.util.Vector;


public class TestActivity
{
	
	public static String indentChar = "\t"; //文件层次缩进字符 
	
	public static void main(
			String args[] )
	{
		new TestActivity().test();
	}
	
	/** 
	 * 客户端测试方法 
	 */
	public void test()
	{
		//根下文件及文件夹 
		Folder root = new Folder( "树根" );
		Folder b1_1 = new Folder( "1_枝1" );
		Folder b1_2 = new Folder( "1_枝2" );
		Folder b1_3 = new Folder( "1_枝3" );
		File l1_1 = new File( "1_叶1" );
		File l1_2 = new File( "1_叶2" );
		File l1_3 = new File( "1_叶3" );
		//b1_2下的文件及文件夹 
		Folder b2_1 = new Folder( "2_枝1" );
		Folder b2_2 = new Folder( "2_枝2" );
		File l2_1 = new File( "2_叶1" );
		//缔造树的层次关系（简单测试，没有重复添加的控制） 
		root.add( b1_1 );
		root.add( b1_2 );
		root.add( l1_1 );
		root.add( l1_2 );
		b1_2.add( b2_1 );
		b1_2.add( b2_2 );
		b1_2.add( l2_1 );
		root.add( l1_3 );
		root.add( b1_3 );
		//控制台打印树的层次 
		outTree( root );
	}
	
	public void outTree(
			Folder folder )
	{
		System.out.println( folder.getName() );
		iterateTree( folder );
	}
	
	/** 
	 * 遍历文件夹，输入文件树 
	 * 
	 * @param folder 
	 */
	public void iterateTree(
			Folder folder )
	{
		Vector<IFile> clist = folder.getAllComponent();
		//todo:遍历之前可以对clist进行排序，这些都不是重点 
		for( Iterator<IFile> it = clist.iterator() ; it.hasNext() ; )
		{
			IFile em = it.next();
			if( em instanceof Folder )
			{
				Folder cm = (Folder)em;
				System.out.println( getIndents( em.getDeep() ) + cm.getName() );
				iterateTree( cm );
			}
			else
			{
				System.out.println( getIndents( em.getDeep() ) + ( (File)em ).getName() );
			}
		}
	}
	
	/** 
	 * 文件层次缩进字符串 
	 * 
	 * @param x 缩进字符个数 
	 * @return 缩进字符串 
	 */
	public static String getIndents(
			int x )
	{
		StringBuilder sb = new StringBuilder();
		for( int i = 0 ; i < x ; i++ )
		{
			sb.append( indentChar );
		}
		return sb.toString();
	}
}

输出结果：

树根
	1_枝1
	1_枝2
		2_枝1
		2_枝2
		2_叶1
	1_叶1
	1_叶2
	1_叶3
	1_枝3