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Java-based middleware for in-memory processing of big data in a distributed environment.
There is a newer version: 3.0.0-beta1
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.ignite.cache.store;

import java.util.Map;
import org.apache.ignite.resources.CacheStoreSessionResource;
import org.apache.ignite.transactions.Transaction;
import org.jetbrains.annotations.Nullable;

/**
 * Session for the cache store operations. The main purpose of cache store session
 * is to hold context between multiple store invocations whenever in transaction. For example,
 * if using JDBC, you can store the ongoing database connection in the session {@link #properties()} map.
 * You can then commit this connection in the {@link CacheStore#sessionEnd(boolean)} method.
 * 
 * {@code CacheStoreSession} can be injected into an implementation of {@link CacheStore} with
 * {@link CacheStoreSessionResource @CacheStoreSessionResource} annotation.
 *
 * @see CacheStoreSessionResource
 */
public interface CacheStoreSession {
    /**
     * Gets transaction spanning multiple store operations, or {@code null} if
     * there is no transaction.
     *
     * @return Transaction belonging to current session.
     */
    public Transaction transaction();

    /**
     * Returns {@code true} if performing store operation within a transaction,
     * {@code false} otherwise. Analogous to calling {@code transaction() != null}.
     *
     * @return {@code True} if performing store operation within a transaction,
     * {@code false} otherwise.
     */
    public boolean isWithinTransaction();

    /**
     * Attaches the given object to this session.
     * 

     * An attached object may later be retrieved via the {@link #attachment()}
     * method. Invoking this method causes any previous attachment to be
     * discarded. To attach additional objects use {@link #properties()} map.
     * 
     * The current attachment may be discarded by attaching {@code null}.
     *
     * @param attachment The object to be attached (or {@code null} to discard current attachment).
     * @return Previously attached object, if any.
     */
    @Nullable public  T attach(@Nullable Object attachment);

    /**
     * Retrieves the current attachment or {@code null} if there is no attachment.
     *
     * @return Currently attached object, if any.
     */
    @Nullable public  T attachment();

    /**
     * Gets current session properties. You can add properties directly to the
     * returned map.
     *
     * @return Current session properties.
     */
    public  Map properties();

    /**
     * Cache name for the current store operation. Note that if the same store
     * is reused between different caches, then the cache name will change between
     * different store operations.
     *
     * @return Cache name for the current store operation.
     */
    public String cacheName();
}