org.gridgain.grid.cache.GridCachePeekMode Maven / Gradle / Ivy

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/* 
 Copyright (C) GridGain Systems. All Rights Reserved.
 
 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.
 */

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*  \____/   /_/     /_/   \_,__/   \____/   \__,_/  /_/   /_/ /_/
*/

package org.gridgain.grid.cache;

import org.jetbrains.annotations.*;

import java.util.*;

/**
 * Enumeration of all supported cache peek modes. Peek modes can be passed into various
 * {@code 'GridCacheProjection.peek(..)'} and {@code GridCacheEntry.peek(..)} methods,
 * such as {@link GridCacheProjection#peek(Object, Collection)},
 * {@link GridCacheEntry#peek()}, and others.
 * 
 * The following modes are supported:
 * 

 * {@link #TX}
 * {@link #GLOBAL}
 * {@link #SMART}
 * {@link #SWAP}
 * {@link #DB}
 * 
 */
public enum GridCachePeekMode {
    /** Peeks value only from in-transaction memory of an ongoing transaction, if any. */
    TX,

    /** Peeks at cache global (not in-transaction) memory. */
    GLOBAL,

    /**
     * In this mode value is peeked from in-transaction memory first using {@link #TX}
     * mode and then, if it has not been found there, {@link #GLOBAL} mode is used to
     * search in committed cached values.
     */
    SMART,

    /** Peeks value only from off-heap or cache swap storage without loading swapped value into cache. */
    SWAP,

    /** Peek value from the underlying persistent storage without loading this value into cache. */
    DB,

    /**
     * Peek value from near cache only (don't peek from partitioned cache).
     * In case of {@link GridCacheMode#LOCAL} or {@link GridCacheMode#REPLICATED} cache,
     * behaves as {@link #GLOBAL} mode.
     */
    NEAR_ONLY,

    /**
     * Peek value from partitioned cache only (skip near cache).
     * In case of {@link GridCacheMode#LOCAL} or {@link GridCacheMode#REPLICATED} cache,
     * behaves as {@link #GLOBAL} mode.
     */
    PARTITIONED_ONLY;

    /** Enumerated values. */
    private static final GridCachePeekMode[] VALS = values();

    /**
     * Efficiently gets enumerated value from its ordinal.
     *
     * @param ord Ordinal value.
     * @return Enumerated value or {@code null} if ordinal out of range.
     */
    @Nullable public static GridCachePeekMode fromOrdinal(byte ord) {
        return ord >= 0 && ord < VALS.length ? VALS[ord] : null;
    }
}