从通过从其他列表添加对象而合并的列表中删除对象

Question

我正在尝试编写一个代码，从ArrayList的实例中移除某些对象。

体系结构：

null

null

代码：

 public interface IRetrieve {

        List<ClassC> getClassCList();

    }

    public class ClassA implements IRetrieve {

        private List<ClassB> classBList;

        public List<ClassB> getClassBList() {
            return classBList;
        }

        public void setClassBList(List<ClassB> classBList) {
            this.classBList = classBList;
        }

        public List<ClassC> getClassCList(){

            List<ClassC> classCList = new ArrayList<>();

            for(ClassB classB: classBList){
                classCList.addAll(classB.getClassCList());
            }

            return classCList;
        }
    }

    public class ClassB {

        private List<ClassC> classCList;

        public List<ClassC> getClassCList() {
            return classCList;
        }

        public void setClassCList(List<ClassC> classCList) {
            this.classCList = classCList;
        }
    }


    public class ClassC {

        private String identifier;

        public String getIdentifier() {
            return identifier;
        }

        public void setIdentifier(String identifier) {
            this.identifier = identifier;
        }
    }

    public class Test {
    public static void main(String[] args) {
        ClassA classA = new ClassA();
        classA.setClassBList(new ArrayList<ClassB>());
        for (int i = 0; i < 5; i++) {
            ClassB classB = new ClassB();
            classB.setClassCList(new ArrayList<ClassC>());
            for (int j = 0; j < 5; j++) {
                ClassC classC = new ClassC();
                classB.getClassCList().add(classC);
            }
            classA.getClassBList().add(classB);
        }

        removeClassCInstances(classA);
    }


    public static void removeClassCInstances(IRetrieve classA){

        //try removing a specific object from the ClassCList
        //using an instance of ClassA

        List<ClassC> classCList = classA.getClassCList();

        List<ClassC> objectsTobeRemoved = new ArrayList<>();

        for(ClassC classC : classCList){
            if(classC.getIdentifier().equals("1")){
                objectsTobeRemoved.add(classC);
            }
        }

        classCList.removeAll(objectsTobeRemoved);
    }
}

Answer 1

您可以定义API以移除类A中的对象：

public class ClassA {
   ...
   public void removeAll(List<ClassC> objectsToRemove) {
       for(ClassB classB: classBList){
           classB.getClassCList().removeAll(objectsToRemove);
       }
   }
}