构建您自己的自动垃圾收集器: 开发者指南

import java.util.ArrayList;
import java.util.List;

class CustomObject {
    boolean marked = false;
    List<CustomObject> references = new ArrayList<>();
}

class MemoryManager {
    List<CustomObject> heap = new ArrayList<>();
    List<CustomObject> roots = new ArrayList<>();

    CustomObject allocateObject() {
        CustomObject obj = new CustomObject();
        heap.add(obj);
        return obj;
    }

    void addRoot(CustomObject obj) {
        roots.add(obj);
    }

    void removeRoot(CustomObject obj) {
        roots.remove(obj);
    }

    void mark(CustomObject obj) {
        if (!obj.marked) {
            obj.marked = true;
            for (CustomObject ref : obj.references) {
                mark(ref);
            }
        }
    }

    void sweep() {
        List<CustomObject> newHeap = new ArrayList<>();
        for (CustomObject obj : heap) {
            if (obj.marked) {
                obj.marked = false;
                newHeap.add(obj);
            }
        }
        heap = newHeap;
    }

    void collectGarbage() {
        // Mark phase
        for (CustomObject root : roots) {
            mark(root);
        }

        // Sweep phase
        sweep();
    }
}