https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.internal.jshell.tool;


The required functionality jshell uses for persistent storage.  Implementable
by both Preferences API and Map.

/**
 * The required functionality jshell uses for persistent storage.  Implementable
 * by both Preferences API and Map.
 */
interface PersistentStorage {

    
Removes all of the preferences (key-value associations) in
preferences.

Throws:
  • IllegalStateException – if this operation cannot be completed
because of the state of the system.
/**
     * Removes all of the preferences (key-value associations) in
     * preferences.
     *
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     */
    void clear();

    
Returns all of the keys that have an associated value in
preferences.

Throws:
Returns:an array of the keys that have an associated value in this
preference node.
/**
     * Returns all of the keys that have an associated value in
     * preferences.
     *
     * @return an array of the keys that have an associated value in this
     * preference node.
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     */
    String[] keys();

    
Returns the value associated with the specified key in preferences.

Params:
  • key – key whose associated value is to be returned.
Throws:
Returns:the value associated with key, or null if no value is associated with key.
/**
     * Returns the value associated with the specified key in preferences.
     *
     * @param key key whose associated value is to be returned.
     * @return the value associated with {@code key}, or {@code null} if no
     * value is associated with {@code key}.
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     * @throws NullPointerException if {@code key} is {@code null}.
     */
    String get(String key);

    
Associates the specified value with the specified key in this
preference node.

Params:
  • key – key with which the specified value is to be associated.
  • value – value to be associated with the specified key.
Throws:
/**
     * Associates the specified value with the specified key in this
     * preference node.
     *
     * @param key key with which the specified value is to be associated.
     * @param value value to be associated with the specified key.
     * @throws NullPointerException if key or value is {@code null}.
     * @throws IllegalArgumentException if key or value are too long.
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     */
    void put(String key, String value);

    
Removes the value associated with the specified key in preferences,
if any.

Params:
  • key – key whose mapping is to be removed from the preference
node.
Throws:
/**
     * Removes the value associated with the specified key in preferences,
     * if any.
     *
     * @param key key whose mapping is to be removed from the preference
     * node.
     * @throws NullPointerException if {@code key} is {@code null}.
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     */
    void remove(String key);

    
Forces any changes in the contents of this preferences to be stored.
Once this method returns successfully, it is safe to assume that all
changes have become as permanent as they are going to be.


Implementations are free to flush changes into the persistent store
at any time. They do not need to wait for this method to be called.

Throws:
  • IllegalStateException – if this operation cannot be completed
because of the state of the system.
/**
     * Forces any changes in the contents of this preferences to be stored.
     * Once this method returns successfully, it is safe to assume that all
     * changes have become as permanent as they are going to be.
     * <p>
     * Implementations are free to flush changes into the persistent store
     * at any time. They do not need to wait for this method to be called.
     *
     * @throws IllegalStateException if this operation cannot be completed
     * because of the state of the system.
     */
    void flush();

}