如何通过委托实现车辆的长尾词追踪功能？

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基于委托的车辆追踪器，包含车辆位置和不可修改的视图。

javapublic class DelegatingVehicleTracker { private final ConcurrentHashMap locations; private final Map unmodifiableMap;

public DelegatingVehicleTracker(Map points) { locations=new ConcurrentHashMap(); for (Map.Entry entry : points.entrySet()) { locations.put(entry.getKey(), entry.getValue()); } unmodifiableMap=Collections.unmodifiableMap(locations); }}

基于委托的车辆追踪器

/** 基于委托的车辆追踪器 */ public class DelegatingVehicleTracker { private final ConcurrentHashMap locations; private final Map unmodifiableMap; public DelegatingVehicleTracker(Map points) { locations = new ConcurrentHashMap (); unmodifiableMap = Collections.unmodifiableMap(locations); } public Map getLocations() { return unmodifiableMap; } public Point getLocation(String id) { return locations.get(id); } public void setLocation(String id, int x, int y) { if (locations.replace(id, new Point(x, y)) != null) System.out.println("invalid vehicle name : " + id); } }