/*
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* The contents of this file are subject to the terms of the Common Development and
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* Distribution License (the License). You may not use this file except in compliance with the
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* License.
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*
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* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
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* specific language governing permission and limitations under the License.
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*
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* When distributing Covered Software, include this CDDL Header Notice in each file and include
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* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
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* Header, with the fields enclosed by brackets [] replaced by your own identifying
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* information: "Portions Copyright [year] [name of copyright owner]".
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*
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* Copyright 2016 ForgeRock AS.
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*/
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package org.opends.server.backends.pluggable.spi;
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import org.forgerock.opendj.ldap.ByteSequence;
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import java.util.NoSuchElementException;
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/**
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* Implementation of an empty {@link Cursor}, for simulating no records to cursor on.
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* <p>
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* Cursor behaves as follows:
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* <ul>
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* <li>Positioning to a key or index will fail, returning {@code false}.</li>
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* <li>Reading the key or value will return {@code null}.</li>
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* <li>Deleting the current element is not supported, {@link UnsupportedOperationException} will be thrown.</li>
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* </ul>
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* </p>
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*
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* @param <K> Type of the simulated record's key
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* @param <V> Type of the simulated record's value
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*/
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public final class EmptyCursor<K, V> implements Cursor<K, V>
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{
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@Override
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public boolean positionToKey(ByteSequence key)
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{
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return false;
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}
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@Override
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public boolean positionToKeyOrNext(ByteSequence key)
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{
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return false;
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}
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@Override
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public boolean positionToLastKey()
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{
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return false;
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}
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@Override
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public boolean positionToIndex(int index)
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{
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return false;
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}
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@Override
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public boolean next()
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{
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return false;
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}
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@Override
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public boolean isDefined()
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{
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return false;
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}
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@Override
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public K getKey() throws NoSuchElementException
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{
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return null;
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}
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@Override
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public V getValue() throws NoSuchElementException
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{
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return null;
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}
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@Override
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public void delete() throws NoSuchElementException, UnsupportedOperationException
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{
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throw new UnsupportedOperationException();
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}
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@Override
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public void close()
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{
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// Nothing to do
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}
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}
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