在Java中限制HashMap的最大大小 [英] Limiting the max size of a HashMap in Java
问题描述
我想限制一个 HashMap
的最大大小,以获取我正在实现的各种哈希算法的指标。我在 HashMap
的重载构造函数之一中查看了loadfactor。
HashMap(int initialCapacity,float loadFactor)
我尝试在构造函数中将loadFactor设置为0.0f这意味着我不希望HashMap在EVER中增长)但是 javac
调用这个方法是无效的:
<$ p $ < init>(HashMap.java:177)$ b $在java.util.HashMap中非法加载因子:0.0
< init>(HashMap.java:177)$ b $ < init>(Main.java:20)
at hashtables.Main.main(Main.java:70)Java结果:1
在hashtables.CustomHash中。 / pre>
是否有另一种方法来限制 HashMap
的大小,使其不会增长?
c> public class InstrumentedHashMap< K,V>实现Map< K,V> {
私人地图< K,V>地图;
public InstrumentedHashMap(){
map = new HashMap< K,V>(); (键),
}
public boolean put(K key,V value){
if(map.size()> = MAX&&!map.containsKey ){
return false;
} else {
map.put(...);
返回true;
}
}
...
}
I want to limit the maximum size of a HashMap
to take metrics on a variety of hashing algorithms that I'm implementing. I looked at the loadfactor in one of HashMap
's overloaded constructors.
HashMap(int initialCapacity, float loadFactor)
I tried setting the loadFactor to 0.0f in the constructor (meaning that I don't want the HashMap to grow in size EVER) but javac
calls this invalid:
Exception in thread "main" java.lang.IllegalArgumentException: Illegal load factor: 0.0
at java.util.HashMap.<init>(HashMap.java:177)
at hashtables.CustomHash.<init>(Main.java:20)
at hashtables.Main.main(Main.java:70) Java Result: 1
Is there another way to limit the size of HashMap
so it doesn't grow ever?
Sometimes simpler is better.
public class InstrumentedHashMap<K, V> implements Map<K, V> {
private Map<K, V> map;
public InstrumentedHashMap() {
map = new HashMap<K, V>();
}
public boolean put(K key, V value) {
if (map.size() >= MAX && !map.containsKey(key)) {
return false;
} else {
map.put(...);
return true;
}
}
...
}
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