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/*******************************************************************************
* Copyright (c) 2013 uniVocity Software Pty Ltd. All rights reserved.
* This file is subject to the terms and conditions defined in file
* 'LICENSE.txt', which is part of this source code package.
******************************************************************************/
package com.univocity.api.engine;
import com.univocity.api.*;
import com.univocity.api.config.*;
/**
* User provided storage mechanism to enable the persistent scope ({@link EngineScope#PERSISTENT}).
*
* A persistent scope ideally retains values produced by a {@link DataIntegrationEngine} even after the application stops.
* Its expected to be able to restore these values once the application is started again, so no expensive processing has to happen
*
*
The ScopeStorageProvider instance will have its {@link #initialize()} method when a {@link DataIntegrationEngine} is loaded
* from {@link Univocity}. A call to {@link #deactivate()} is made when the engine is shut down.
*
*
uniVocity will obtain instances of this interface through {@link EngineConfiguration#getPersistentScopeStorageProvider()}.
*
* @see EngineConfiguration
* @see DataIntegrationEngine
* @see EngineScope
*
* @author uniVocity Software Pty Ltd - [email protected]
*
*/
public interface ScopeStorageProvider {
/**
* Obtains a value associated with a key in the scope storage.
* @param key the key that refers to a value stored in this scope
* @return the value associated with the given key, or null if this scope does not contain a value for the key.
*/
public Object getValue(Object key);
/**
* Associates a value to a key in this scope storage.
* @param key the key to be associated with a value in this storage
* @param value the value associated with the given key
* @return the previous value associated with the given key, if any.
*/
public Object setValue(Object key, Object value);
/**
* Queries the storage for the presence of a key.
* @param key that refers to a value stored in this scope
* @return true if this storage contains the given key, false otherwise.
*/
public boolean contains(Object key);
/**
* Initializes the storage provider. This is invoked when a {@link DataIntegrationEngine} that uses this storage provider is started.
*/
public void initialize();
/**
* Deactivates the storage provider. This is invoked when the {@link DataIntegrationEngine} that uses this storage provider is shut down.
*/
public void deactivate();
}