HashMapCache.java

/*
 * Copyright (C) 2014 SCVNGR, Inc. d/b/a LevelUp
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.scvngr.levelup.core.ui.view;

import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

import com.scvngr.levelup.core.annotation.VisibleForTesting;
import com.scvngr.levelup.core.annotation.VisibleForTesting.Visibility;
import com.scvngr.levelup.core.ui.view.LevelUpQrCodeGenerator.LevelUpQrCodeImage;

import net.jcip.annotations.ThreadSafe;

import java.util.concurrent.ConcurrentHashMap;

/**
 * A simple in-memory cache of the codes. The cache is static, so it'll be shared across all
 * instances of this class.
 */
@ThreadSafe
public final class HashMapCache implements LevelUpCodeCache {
    private static final ConcurrentHashMap<String, LevelUpQrCodeImage> CACHE =
            new ConcurrentHashMap<String, LevelUpQrCodeImage>();

    @Override
    public void putCode(@NonNull final String key, @NonNull final LevelUpQrCodeImage image) {
        CACHE.put(key, image);
    }

    @Override
    @Nullable
    public LevelUpQrCodeImage getCode(@NonNull final String key) {
        return CACHE.get(key);
    }

    @Override
    public boolean hasCode(@NonNull final String key) {
        return CACHE.containsKey(key);
    }

    /**
     * Clears the cache.
     */
    @VisibleForTesting(visibility = Visibility.PRIVATE)
    /* package */void clear() {
        CACHE.clear();
    }
}