@文心快码return an empty collection instead of null 文心快码 在编程中,返回一个空集合而不是null是一个常见的最佳实践,这可以避免NullPointerException并简化代码的处理逻辑。以下是如何在不同编程语言中实现这一点的指南: 1. 识别需要返回空集合的情景 当函数或方法预期返回一个集合类型(如列表、元组、字典等)...
A collection-valued method can be made to return the same immutable empty collection every time it needs to return an empty collection. /** * The right way to return a copy of a collection * @return an array containing all of the cheeses in the shop. */ public List<Cheese> getCheeseL...
所以可定义成static final(对于数组)或者Collections.emptyList()/emptyMap()/emptySet()来公用同一个对象,减少性能影响。 代码2: 1//The right way to return an array from a collection 2privatefinalList<Cheese> cheesesInStock = ...; 3privatestaticfinalCheese[] EMPTY_CHEESE_ARRAY =newCheese[0]; 4...
package com.xiaowang.collection_; import java.util.*; /** * @Author 小王 * @DATE: 2022/4/12 */ public class CollectionMethod { public static void main(String[] args) { List arrayList = new ArrayList();//下面去添加元素 List arrayList1 = new ArrayList();//创建一个空的集合 //1.1.a...
41. Return an empty array or collection instead of a null value for methods that return an array or collection Some APIs intentionally return a null reference to indicate that instances are unavailable. This practice can lead to denial-of-service vulnerabilities when the client code fails to exp...
有时候,我们需要在方法中返回一个空的列表。在Java中,可以使用Collections.emptyList()方法来返回一个空的不可变列表。这个方法返回的列表不支持添加和删除元素,所以可以确保返回的列表是空的。 下面是一个示例代码,演示了如何在Java中返回一个空的列表:
Java 中的许多集合类,例如ArrayList、HashSet和TreeMap都是可变的。这意味着您可以更改它们(例如,通过添加项目或清除它们)。这意味着在编写不可变类时必须小心,集合字段的 getter 返回一个副本。 例如,您应该这样做: public final class Example { private final List<Integer> list; ...
protectedCollection<? extends State> computeCallFlow(SootMethod caller, Statement returnSite, Statement callSite, InvokeExpr invokeExpr, Val fact, SootMethod callee, Stmt calleeSp) {if(!callee.hasActiveBody())returnCollections.emptySet();if(calleeSpinstanceofThrowStmt) {returnCollections.emptySet();...
Version affected: Mockito: 4.x & 5.x If you create a mock with RETURN_DEEP_STUBS, then any method that returns a collection will, by default, return an empty collection, i.e. isEmpty returns true, etc. This is great, as it means no addit...
privateSet<T> intersection(Collection<T> first, Collection<T> second) { // intersection with an empty collection is empty if(isNullOrEmpty(first) || isNullOrEmpty(second)) returnnewHashSet<>(); returnfirst.stream() .filter(second::contains) ...