Extend an existing collection class that already implements Iterable (and therefore already supports for/in).

扩展现有的、已经实现了 Iterable（因此也就已经支持 for/in）的集合类。

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Data: An object; a generic reference that is carried along to listeners; often a collection class (such as a Vector or Hashtable) or a customized data object.

data：一个对象；传递给侦听程序的一般引用；常常是一个集合类(如vector或Hashtable)或一个定制的数据对象。

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Keeping the reference to the property change listener means the Person POJO has to keep some kind of collection class (such as ArrayList) to contain all the references.

保持引用属性变更监听器意味着Person POJO必须保留某种类型的集合类(例如arraylist)来包含所有引用。

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The Peggy Guggenheim Collection houses a first-class collection of 20th-century art from Dali to Duchamp in a beautiful white palazzo on the Grand Canal, and the Punta della Dogana, a contemporary art centre at the tip of Dorsoduro, contains the modern art collection of Francois Pinault, the CEO of Kering, which owns labels like Gucci and Saint Laurent.

BBC: Living in: Venice

The Vatican Observatory is located inside the palazzo, complete with a telescope and a world-class collection of meteorites.

NPR: Vatican Sends Message: Pope's Retirement For Real

Heavily endowed during the Great Depression it was able to amass a world-class collection at fire sale prices.

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