CacheProvider.java

/**
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.geowebcache.storage.blobstore.memory;

import java.util.List;

import org.geowebcache.storage.TileObject;
import org.geowebcache.storage.blobstore.memory.CacheConfiguration.EvictionPolicy;

/**
 * Interface providing access to a cache object. It must be used by the {@link MemoryBlobStore} class for caching {@link TileObject} instances. This
 * cache should be configured only with the setConfiguration method and should be modified by calling in sequence: resetCache() and
 * setConfiguration(). Users should be able to add and remove Layers that should not be cached.
 * 
 * @author Nicola Lagomarsini GeoSolutions
 */
public interface CacheProvider {

    /**
     * Returns the {@link TileObject} for the selected id
     */
    public TileObject getTileObj(TileObject obj);

    /**
     * Insert a {@link TileObject} in cache.
     * 
     * @param obj
     */
    public void putTileObj(TileObject obj);

    /**
     * Removes a {@link TileObject} from cache.
     * 
     * @param obj
     */
    public void removeTileObj(TileObject obj);

    /**
     * Removes all the {@link TileObject}s for the related layer from cache.
     * 
     * @param layername
     */
    public void removeLayer(String layername);

    /**
     * Removes all the cached {@link TileObject}s
     */
    public void clear();

    /**
     * Resets the Cache status and requires to reconfigure it by calling setConfiguration(),
     */
    public void reset();

    /**
     * Returns a {@link CacheStatistics} object containing the current cache statistics.
     */
    public CacheStatistics getStatistics();

    /**
     * Sets the CacheConfiguration to use
     * 
     * @param configuration
     */
    void configure(CacheConfiguration configuration);

    /**
     * Add a new Layer that should not be cached
     * 
     * @param layername
     */
    public void addUncachedLayer(String layername);

    /**
     * Remove a Layer so that it can be cached again
     * 
     * @param layername
     */
    public void removeUncachedLayer(String layername);

    /**
     * Checks if the Layer must be cached or not
     * 
     * @param layername
     * @return true if the Layer should not be cached
     */
    public boolean containsUncachedLayer(String layername);

    /**
     * Returns a list of the supported {@link EvictionPolicy} of the cache Provider
     * 
     * @return a list containing the supported eviction policy
     */
    public List<EvictionPolicy> getSupportedPolicies();

    /**
     * Indicates if the CacheProvider configuration can be changed.
     * 
     * @return a boolean indicating if the cache configuration can be changed or not
     */
    public boolean isImmutable();

    /**
     * Indicates if this {@link CacheProvider} object can be used
     * 
     * @return a boolean indicating that the {@link CacheProvider} can be used for caching
     */
    public boolean isAvailable();
    
    /**
     * Name of the {@link CacheProvider}
     * 
     * @return a String with the Cache Provider name
     */
    public String getName();
}