Exploring the essence of Java Iterator and Iterable: revealing the underlying principles of Java collection traversal

php editor Xigua Java Iterator and Iterable's essence exploration topic will deeply analyze the underlying principles of Java collection traversal. Through the discussion of Iterator and Iterable, the core mechanism of collection traversal in Java is revealed, helping readers gain a deeper understanding of the design and implementation of the Java collection framework.

List<String> names = new ArrayList<>();
names.add("Alice");
names.add("Bob");
names.add("Carol");

// 获取 Iterator 实例
Iterator<String> iterator = names.iterator();

// 遍历集合元素
while (iterator.hasNext()) {
String name = iterator.next();
System.out.println(name);
}

The Iterable interface is the sister interface of Iterator. It defines the iterator() method, which is used to return an Iterator instance of the collection. The Iterable interface is more convenient to use than Iterator. When using Iterable to traverse a collection, you can directly use the for-each statement without explicitly obtaining an Iterator instance.

for (String name : names) {
System.out.println(name);
}

The underlying implementation of Iterator and Iterable depends on the specific implementation of the collection type. For example, for ArrayList, its Iterator instance is actually a pointer pointing to the element in the collection. Each time the next() method is called, the pointer will be moved to The next element. For LinkedList, its Iterator instance is actually a linked list node, and each call to the next() method will move to the next linked list node.

Understanding the underlying principles of Iterator and Iterable helps us better understand how the Java collection framework works and write more efficient and robust code. This article's in-depth exploration of Iterator and Iterable can help Java programmers improve their understanding of the Java collection framework and write more elegant and efficient code.

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