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分享【Java 1.8】LinkedList：checkElementIndex 和 checkPositionIndex 的疑惑
在翻看 Java 1.8 源码发现，LinkedList 里面 checkElementIndex 和 checkPositionIndex 的实现基本一致，那是出于什么目的去实现两个方法呢？
源码：
源码：
/**
* Tells if the argument is the index of an existing element.
*/
private boolean isElementIndex(int index) {
return index >= 0 && index < size;
}
/**
* Tells if the argument is the index of a valid position for an
* iterator or an add operation.
*/
private boolean isPositionIndex(int index) {
return index >= 0 && index <= size;
}
/**
* Constructs an IndexOutOfBoundsException detail message.
* Of the many possible refactorings of the error handling code,
* this "outlining" performs best with both server and client VMs.
*/
private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+size;
}
private void checkElementIndex(int index) {
if (!isElementIndex(index))
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
private void checkPositionIndex(int index) {
if (!isPositionIndex(index))
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
...全文
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usecf 2020-07-16
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isElementIndex //Tells if the argument is the index of an existing element.
isPositionIndex // Tells if the argument is the index of a valid position for an
看这两注释 一个是判断是否存在该元素
另外一个是索引越界
