com.newrelic.agent.service.analytics.LimitedSizeHashMap Maven / Gradle / Ivy

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Jar required to run with a java application to monitor performance.

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/*
 *
 *  * Copyright 2020 New Relic Corporation. All rights reserved.
 *  * SPDX-License-Identifier: Apache-2.0
 *
 */

package com.newrelic.agent.service.analytics;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

public class LimitedSizeHashMap implements Map {

    private final int max;
    private final Map map;

    public LimitedSizeHashMap(int max) {
        this.max = max;
        this.map = new HashMap<>();
    }

    @Override
    public int size() {
        return map.size();
    }

    @Override
    public boolean isEmpty() {
        return map.isEmpty();
    }

    @Override
    public boolean containsKey(Object key) {
        return map.containsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
        return map.containsValue(value);
    }

    @Override
    public V get(Object key) {
        return map.get(key);
    }

    @Override
    public V put(K key, V value) {
        if (map.size() < max) {
            return map.put(key, value);
        }
        return null;
    }

    @Override
    public V remove(Object key) {
        return map.remove(key);
    }

    @Override
    public void putAll(Map m) {
        for (Map.Entry entry : m.entrySet()) {
            put(entry.getKey(), entry.getValue());
            if (map.size() >= max) {
                // fail fast
                return;
            }
        }
    }

    public void putAllIfAbsent(Map m) {
        for (Map.Entry entry : m.entrySet()) {
            if (!map.containsKey(entry.getKey())) {
                put(entry.getKey(), entry.getValue());
                if (map.size() >= max) {
                    // fail fast
                    return;
                }
            }
        }
    }

    @Override
    public void clear() {
        map.clear();
    }

    @Override
    public Set keySet() {
        return map.keySet();
    }

    @Override
    public Collection values() {
        return map.values();
    }

    @Override
    public Set> entrySet() {
        return map.entrySet();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        LimitedSizeHashMap that = (LimitedSizeHashMap) o;
        return max == that.max &&
                Objects.equals(map, that.map);
    }

    @Override
    public int hashCode() {
        return Objects.hash(max, map);
    }
}