Java Iterator

import java.util.Iterator; import java.util.NoSuchElementException; /*重新定义Iterator时，需要重载hasNext()，以及next()函数 */ public class OHIterator implements Iterator<OHRequest> { OHRequest curr; public OHIterator(OHRequest original) { curr = original; } public boolean isGood(String description) { return description != null && description.length() > 5; } @Override public boolean hasNext() { /*if(curr == null) return false; */ while(curr!= null && !isGood(curr.description)) { curr = curr.next; } return curr != null; } public OHRequest next() { if(!hasNext()) { throw new NoSuchElementException(); } OHRequest currRequest = curr; curr = curr.next; return currRequest; } }

2.新的迭代器 的接口为Iterator类

public interface Iterator<T> { boolean hasNext(); T next(); }

3.想让自己定义的类支持Foreach循环，需要继承Interable类

import java.util.Iterator; import java.util.NoSuchElementException; //继承Iterable， 为了支持foreach循环 public class OfficeHourQueue implements Iterable<OHRequest> { OHRequest queue; public OfficeHourQueue(OHRequest queue) { this.queue = queue; } @Override public Iterator<OHRequest> iterator() { return new OHIterator(queue); } public static void main(String[] args) { OHRequest s1 = new OHRequest("Failing my test for get in arrayDeque, NPE", "Pam", null); OHRequest s2 = new OHRequest("conceptual: what is dynamic method selection", "Michael", s1); OHRequest s3 = new OHRequest("git: what does checkout do.", "Jim", s2); OHRequest s4 = new OHRequest("help", "Dwight", s3); OHRequest s5 = new OHRequest("debugging get(i)", "Creed", s4 ); OfficeHourQueue q = new OfficeHourQueue(s5); for(OHRequest o : q) { System.out.println(o.name); } } }

 

转载于:https://www.cnblogs.com/Shinered/p/10651536.html

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