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package org.hisp.dhis.antlr.cache;

/*
 * Copyright (c) 2004-2020, University of Oslo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * Neither the name of the HISP project nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import com.google.common.base.Optional;

import java.util.Collection;

public interface Cache
{
    /**
     * Returns the value associated with the {@code key} in this cache instance,
     * or {@code Optional.empty()} if there is no cached value.Note: This method
     * will NOT return the defaultValue in case of absence of associated cache
     * value.
     *
     * @param key the key whose associated value is to be retrieved
     * @return the value wrapped in Optional, or {@code Optional.empty()}
     */
    Optional getIfPresent( String key );

    /**
     * Returns the value associated with the {@code key} in this cache instance,
     * or {@code defaultValue} if there is no cached value.Note: This method
     * will return the defaultValue in case of absence of associated cache
     * value. But will not store the default value into the cache.
     *
     * @param key the key whose associated value is to be retrieved
     * @return the value wrapped in Optional, or
     *         {@code Optional of defaultValue}
     */
    Optional get( String key );

    /**
     * Returns the value mapped to {@code key} in this cache instance, obtaining
     * that value from the {@code mappingFunction} if necessary. This method
     * provides a simple substitute for the conventional "if cached, return;
     * otherwise create, cache and return" pattern. If value is null, the given
     * mapping function is evaluated and inserted into this cache unless
     * {@code null}. Note: This method will return the defaultValue in case of
     * absence of associated cache value. But will not store the default value
     * into the cache.
     *
     * @param key the key for retrieving the value
     * @param mappingFunction the function to compute a value.
     * @return an optional containing current (existing or computed) value, or
     *         Optional.empty() if the computed value is null
     * @throws IllegalArgumentException if the specified mappingFunction is null
     */
    Optional get( String key, MappingFunction mappingFunction );

    /**
     * Returns a collection of all the values in the cache
     *
     * @return collection with all cached values
     */
    Collection getAll();

    /**
     * Associates the {@code value} with the {@code key} in this cache. If the
     * cache previously contained a value associated with the {@code key}, the
     * old value is replaced by the new {@code value}.Prefer
     * {@link #get(String, MappingFunction)} when using the conventional "if cached,
     * return; otherwise create, cache and return" pattern.
     *
     * @param key the key for the value
     * @param value value to be mapped to the key
     * @throws IllegalArgumentException if the specified value is null
     */
    void put( String key, V value );

    /**
     * Discards any cached value for the {@code key}. The behavior of this
     * operation is undefined for an entry that is being loaded and is otherwise
     * not present.
     *
     * @param key the key whose mapping is to be removed from the cache
     */
    void invalidate( String key );

    /**
     * Discards all entries in this cache instance. If a shared cache is used,
     * this method does not clear anything.
     */
    void invalidateAll();

    /**
     * Returns the type of the cache. IN_MEMORY or REDIS or NONE.
     *
     * @return the type of cache
     */
    CacheType getCacheType();
}