接着上一章节,我们继续介绍填充容器。

这一章节我们结束还有一种填充容器的方式:addAll

样例:

package com.ray.ch15;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashSet;

public class Test {
	public static void main(String[] args) {
		MyCollection<String> myCollection = new MyCollection<String>(
				new MyGenerator(), 25);//在构造器填充
		System.out.println(Arrays.toString(myCollection.toArray()));
		LinkedHashSet<String> set = new LinkedHashSet<String>(myCollection);
		System.out.println(Arrays.toString(set.toArray()));
		set.clear();
		set.addAll(myCollection);//还有一种方式
		System.out.println(Arrays.toString(set.toArray()));
	}
}

interface Generator<T> {
	T next();
}

class MyCollection<T> extends ArrayList<T> {
	private static final long serialVersionUID = 1L;

	public MyCollection(Generator<T> generator, int count) {
		for (int i = 0; i < count; i++) {
			add(generator.next());
		}
	}
}

class MyGenerator implements Generator<String> {

	private String strPool = "The annual expansion rate for "
			+ "industrial output will be around 6 percent this year, "
			+ "well below this year's GDP growth, which is likely to be "
			+ "about 7 percent, the Ministry of Industry and Information "
			+ "Technology said, adding that such a situation was happening "
			+ "for the first time in nearly two decades.";

	private int index = 0;

	@Override
	public String next() {
		return strPool.split(" ")[index++];
	}
}

输出:

[The, annual, expansion, rate, for, industrial, output, will, be, around]
[The, annual, expansion, rate, for, industrial, output, will, be, around]
[The, annual, expansion, rate, for, industrial, output, will, be, around]


我来解释一下上面的代码。有几个须要注意的地方:

(1)上面继续前几个篇幅所提到的生成器,我们通过泛型生成器来生成相关的对象。

这样的方式创建的对象具备灵活性,不像系统提供的nCopy方法,仅仅能创建单一的对象。

(2)创建一个自己的容器(继承Arraylist),它是用来装载生成器创建的对象,继承某个容器,能够方便的在构造器里面调用add方法。也具备容器的特性

(3)在main方法里面展现了两种填充容器的方式,一个是直接在构造器里面加入,一个是使用addAll方法,这两种方法都是接收Collection类型的容器,因此我们不管生成什么的容器,都能够add进去。


总结:这一章节展现了还有一种填充容器的方式。


这一章节就到这里,谢谢。

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