【IT168 技术文档】本篇将讲解一下closure中的owner，以及this,delegate以及owner三者间的关系。

　　先让我们来看个例子：

　　class OwnerDemo {
　　def outerClosure = {
　　println "the owner of outerClosure: " + owner
　　def innerClosure = {
　　println "the owner of innerClosure: " + owner
　　def innestClosure = {
　　println "the owner of innestClosure: " + owner
　　}
　　innestClosure()
　　}
　　innerClosure()
　　}
　　}
　　def ownerDemo = new OwnerDemo()
　　ownerDemo.outerClosure()

　　运行结果：

　　the owner of outerClosure: OwnerDemo@eccfe7

　　the owner of innerClosure: OwnerDemo$_closure1@4745cf

　　the owner of innestClosure: OwnerDemo$_closure1_closure2@109dcbb

　　注意：OwnerDemo$_closure1指的是outerClosure的类名，而OwnerDemo$_closure1_closure2指的是innerClosure的类名

　　通过这个例子，大家就清楚了，closure的owner引用的是该closure的‘拥有者’

　　那么this, delegate以及owner有什么关系呢?

　　隐式变量delegate的默认值为owner，

　　如果closure没有‘嵌套’在其他closure中，那么该closure的owner的值为this;

　　否则该closure的owner引用的是‘直接包含’该closure的closure

　　让我们用事实来说话吧：

　　class OwnerDemo {
　　def outerClosure = {
　　println "the owner of outerClosure: " + owner
　　println "the delegate of outerClosure: " + delegate
　　println "this in the outerClosure: " + this
　　def innerClosure = {
　　println "the owner of innerClosure: " + owner
　　println "the delegate of innerClosure: " + delegate
　　println "this in the innerClosure: " + this
　　def innestClosure = {
　　println "the owner of innestClosure: " + owner
　　println "the delegate of innestClosure: " + delegate
　　println "this in the innestClosure: " + this
　　}
　　println "innestClosure: " + innestClosure
　　innestClosure()
　　}
　　println "innerClosure: " + innerClosure
　　innerClosure()
　　}
　　}
　　def ownerDemo = new OwnerDemo()
　　def outerClosure = ownerDemo.outerClosure
　　println "outerClosure: " + outerClosure
　　outerClosure()

　　运行结果：

　　outerClosure: OwnerDemo$_closure1@10cc9b4

　　the owner of outerClosure: OwnerDemo@8e7f54

　　the delegate of outerClosure: OwnerDemo@8e7f54

　　this in the outerClosure: OwnerDemo@8e7f54

　　innerClosure: OwnerDemo$_closure1_closure2@1eb1db2

　　the owner of innerClosure: OwnerDemo$_closure1@10cc9b4

　　the delegate of innerClosure: OwnerDemo$_closure1@10cc9b4

　　this in the innerClosure: OwnerDemo@8e7f54

　　innestClosure: OwnerDemo$_closure1_closure2_closure3@12a78ee

　　the owner of innestClosure: OwnerDemo$_closure1_closure2@1eb1db2

　　the delegate of innestClosure: OwnerDemo$_closure1_closure2@1eb1db2

　　this in the innestClosure: OwnerDemo@8e7f54

　　大家可以从其中值的关系看出this, delegate以及owner三者的关系与我们之前所说的相符　:)