com.google.common.base.ReferenceType.java Source code

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Here is the source code for com.google.common.base.ReferenceType.java

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/*
 * Copyright (C) 2007 Google Inc.
 *
 * 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.
 */

package com.google.common.base;

/**
 * Reference type. Used to specify what type of reference to keep to a
 * referent.
 *
 * @see java.lang.ref.Reference
 * @author Bob Lee
 */
public enum ReferenceType {

    /**
     * Prevents referent from being reclaimed by the garbage collector.
     */
    STRONG,

    /**
     * Referent reclaimed in an LRU fashion when the VM runs low on memory and
     * no strong references exist.
     *
     * @see java.lang.ref.SoftReference
     */
    SOFT,

    /**
     * Referent reclaimed when no strong or soft references exist.
     *
     * @see java.lang.ref.WeakReference
     */
    WEAK,

    /**
     * Similar to weak references except the garbage collector doesn't actually
     * reclaim the referent. More flexible alternative to finalization.
     *
     * @see java.lang.ref.PhantomReference
     */
    PHANTOM;
}