使用Guava的转发装饰器来创建特定的集合 [英] Using Guava's Forwarding Decorators to create specific collections

问题描述

我有多个使用多个Collection参数的方法。

我想让事情更具体，所以我想使用转发装饰器

第一个问题是：

• 这是一个过度使用转发Decoartor，我缺少一个更简单的
  ，我的意思是非常简单感谢Guava
  但仍然？

如果转发装饰器是正确的路径，

到目前为止看起来很好，但是我不确定的是我如何获得基本集合（在这种情况下为ImmutableSet）？

1. 我只是创建一个返回
   delegate的新方法（在界面和类中）？

代码：

接口：

在下面的代码中，我将一个ImmutableSet保存为setA。 / p>

  package com.ps.experiment.forwarding; 
 
 import java.util.Collection; 
 
 public interface ISetA extends Set< String> {} 
  

/ p>

  package com.ps.experiment.forwarding; 
 
 import com.google.common.collect.ForwardingSet; 
 import com.google.common.collect.ImmutableSet; 
 
 public class SetA extends ForwardingSet< String>实现ISetA 
 {
 final ImmutableSet< String>代表; // backing list 
 
 @Override 
 protected ImmutableSet< String> delegate（）
 {
 return this.delegate; 
} 
 
 private SetA（final ImmutableSet< String> strings）
 {
 this.delegate = strings; 
} 
 
 public static ISetA（final ImmutableSet< String> strings）
 {
 return new SetA（strings）; 
} 
} 
  

解决方案

你写的代码是正确的方法。如果您要访问后端集合，只需使 delegate（） public ，而不是 protected 。

I have multiple methods that use multiple Collection parameters.

I wanted to make things more specific so I thought using Forwarding Decorator

The first question that comes to mind is:

• Is it an overkill to use the Forwarding Decoartor, am I missing a something more simpler , I mean this is very simple thanks to Guava but still?

If Forwarding Decorator is the right path then

It seems fine so far, but one thing I am not sure of is how do I get the base collection(ImmutableSet in this case) back?

1. Do I just create a new method (in interface and class) that returns "delegate" ? (If so what would be a good method name?)
2. or is there something more ?

In the following code I am saving a ImmutableSet as setA.

The Code:

Interface:

package com.ps.experiment.forwarding;

import java.util.Collection;

public interface ISetA extends Set<String>{}

Class:

package com.ps.experiment.forwarding;

import com.google.common.collect.ForwardingSet;
import com.google.common.collect.ImmutableSet;

    public class SetA extends ForwardingSet<String> implements ISetA
    {
        final ImmutableSet<String>  delegate;   // backing list

        @Override
        protected ImmutableSet<String> delegate()
        {
            return this.delegate;
        }

        private SetA(final ImmutableSet<String> strings)
        {
            this.delegate = strings;
        }

        public static ISetA of(final ImmutableSet<String> strings)
        {
            return new SetA(strings);
        }
    }

解决方案

The code you wrote is the correct way. If you want to access the back-end collection, simply make delegate() public instead of protected.

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