/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2010 Sun Microsystems, Inc.
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* Portions copyright 2012 ForgeRock AS.
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*/
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package org.forgerock.opendj.ldap.controls;
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import static org.forgerock.opendj.ldap.CoreMessages.*;
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import java.io.IOException;
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import org.forgerock.i18n.LocalizableMessage;
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import org.forgerock.opendj.asn1.ASN1;
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import org.forgerock.opendj.asn1.ASN1Reader;
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import org.forgerock.opendj.asn1.ASN1Writer;
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import org.forgerock.opendj.ldap.ByteString;
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import org.forgerock.opendj.ldap.ByteStringBuilder;
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import org.forgerock.opendj.ldap.DecodeException;
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import org.forgerock.opendj.ldap.DecodeOptions;
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import com.forgerock.opendj.util.StaticUtils;
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import com.forgerock.opendj.util.Validator;
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/**
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* The simple paged results request and response control as defined in RFC 2696.
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* This control allows a client to control the rate at which an LDAP server
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* returns the results of an LDAP search operation. This control may be useful
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* when the LDAP client has limited resources and may not be able to process the
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* entire result set from a given LDAP query, or when the LDAP client is
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* connected over a low-bandwidth connection.
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* <p>
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* This control is included in the searchRequest and searchResultDone messages
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* and has the following structure:
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*
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* <pre>
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* realSearchControlValue ::= SEQUENCE {
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* size INTEGER (0..maxInt),
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* -- requested page size from client
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* -- result set size estimate from server
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* cookie OCTET STRING
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* }
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* </pre>
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* <p>
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* The following example demonstrates use of simple paged results to handle
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* three entries at a time.
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*
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* <pre>
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* ByteString cookie = ByteString.empty();
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* SearchRequest request;
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* SearchResultHandler resultHandler = new MySearchResultHandler();
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* Result result;
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*
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* int page = 1;
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* do {
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System.out.println("# Simple paged results: Page " + page);
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*
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* request = Requests.newSearchRequest(
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"dc=example,dc=com", SearchScope.WHOLE_SUBTREE, "(sn=Jensen)", "cn")
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.addControl(SimplePagedResultsControl.newControl(true, 3, cookie));
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*
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* result = connection.search(request, resultHandler);
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* try {
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* SimplePagedResultsControl control = result.getControl(
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SimplePagedResultsControl.DECODER, new DecodeOptions());
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cookie = control.getCookie();
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} catch (final DecodeException e) {
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// Failed to decode the response control.
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}
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*
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* ++page;
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* } while (cookie.length() != 0);
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* </pre>
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*
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* The search result handler in this case displays pages of results as LDIF on
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* standard out.
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*
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* <pre>
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* private static class MySearchResultHandler implements SearchResultHandler {
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*
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* {@literal @}Override
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* public void handleErrorResult(ErrorResultException error) {
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* // Ignore.
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* }
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*
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* {@literal @}Override
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* public void handleResult(Result result) {
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* // Ignore.
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* }
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*
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* {@literal @}Override
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* public boolean handleEntry(SearchResultEntry entry) {
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* final LDIFEntryWriter writer = new LDIFEntryWriter(System.out);
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* try {
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* writer.writeEntry(entry);
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* writer.flush();
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* } catch (final IOException e) {
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* // The writer could not write to System.out.
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* }
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* return true;
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* }
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*
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* {@literal @}Override
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* public boolean handleReference(SearchResultReference reference) {
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* System.out.println("Got a reference: " + reference.toString());
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* return false;
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* }
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* }
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* </pre>
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*
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* @see <a href="http://tools.ietf.org/html/rfc2696">RFC 2696 - LDAP Control
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* Extension for Simple Paged Results Manipulation </a>
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*/
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public final class SimplePagedResultsControl implements Control {
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/**
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* The OID for the paged results request/response control defined in RFC
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* 2696.
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*/
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public static final String OID = "1.2.840.113556.1.4.319";
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/**
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* A decoder which can be used for decoding the simple paged results
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* control.
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*/
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public static final ControlDecoder<SimplePagedResultsControl> DECODER =
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new ControlDecoder<SimplePagedResultsControl>() {
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public SimplePagedResultsControl decodeControl(final Control control,
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final DecodeOptions options) throws DecodeException {
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Validator.ensureNotNull(control);
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if (control instanceof SimplePagedResultsControl) {
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return (SimplePagedResultsControl) control;
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}
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if (!control.getOID().equals(OID)) {
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final LocalizableMessage message =
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ERR_LDAP_PAGED_RESULTS_CONTROL_BAD_OID.get(control.getOID(), OID);
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throw DecodeException.error(message);
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}
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if (!control.hasValue()) {
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// The control must always have a value.
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final LocalizableMessage message = ERR_LDAP_PAGED_RESULTS_DECODE_NULL.get();
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throw DecodeException.error(message);
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}
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final ASN1Reader reader = ASN1.getReader(control.getValue());
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try {
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reader.readStartSequence();
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} catch (final Exception e) {
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StaticUtils.DEBUG_LOG.throwing("PagedResultsControl.Decoder", "decode", e);
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final LocalizableMessage message =
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ERR_LDAP_PAGED_RESULTS_DECODE_SEQUENCE.get(String.valueOf(e));
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throw DecodeException.error(message, e);
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}
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int size;
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try {
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size = (int) reader.readInteger();
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} catch (final Exception e) {
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StaticUtils.DEBUG_LOG.throwing("PagedResultsControl.Decoder", "decode", e);
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final LocalizableMessage message =
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ERR_LDAP_PAGED_RESULTS_DECODE_SIZE.get(String.valueOf(e));
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throw DecodeException.error(message, e);
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}
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ByteString cookie;
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try {
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cookie = reader.readOctetString();
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} catch (final Exception e) {
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StaticUtils.DEBUG_LOG.throwing("PagedResultsControl.Decoder", "decode", e);
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final LocalizableMessage message =
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ERR_LDAP_PAGED_RESULTS_DECODE_COOKIE.get(String.valueOf(e));
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throw DecodeException.error(message, e);
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}
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try {
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reader.readEndSequence();
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} catch (final Exception e) {
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StaticUtils.DEBUG_LOG.throwing("PagedResultsControl.Decoder", "decode", e);
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final LocalizableMessage message =
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ERR_LDAP_PAGED_RESULTS_DECODE_SEQUENCE.get(String.valueOf(e));
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throw DecodeException.error(message, e);
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}
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return new SimplePagedResultsControl(control.isCritical(), size, cookie);
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}
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public String getOID() {
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return OID;
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}
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};
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/**
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* Creates a new simple paged results control with the provided criticality,
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* size, and cookie.
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*
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* @param isCritical
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* {@code true} if it is unacceptable to perform the operation
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* without applying the semantics of this control, or
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* {@code false} if it can be ignored.
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* @param size
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* The requested page size when used in a request control from
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* the client, or an estimate of the result set size when used in
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* a response control from the server (may be 0, indicating that
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* the server does not know).
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* @param cookie
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* An opaque cookie which is used by the server to track its
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* position in the set of search results. The cookie must be
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* empty in the initial search request sent by the client. For
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* subsequent search requests the client must include the cookie
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* returned with the previous search result, until the server
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* returns an empty cookie indicating that the final page of
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* results has been returned.
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* @return The new control.
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* @throws NullPointerException
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* If {@code cookie} was {@code null}.
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*/
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public static SimplePagedResultsControl newControl(final boolean isCritical, final int size,
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final ByteString cookie) {
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Validator.ensureNotNull(cookie);
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return new SimplePagedResultsControl(isCritical, size, cookie);
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}
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/**
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* The control value size element, which is either the requested page size
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* from the client, or the result set size estimate from the server.
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*/
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private final int size;
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/**
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* The control value cookie element.
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*/
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private final ByteString cookie;
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private final boolean isCritical;
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private SimplePagedResultsControl(final boolean isCritical, final int size,
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final ByteString cookie) {
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this.isCritical = isCritical;
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this.size = size;
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this.cookie = cookie;
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}
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/**
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* Returns the opaque cookie which is used by the server to track its
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* position in the set of search results. The cookie must be empty in the
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* initial search request sent by the client. For subsequent search requests
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* the client must include the cookie returned with the previous search
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* result, until the server returns an empty cookie indicating that the
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* final page of results has been returned.
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*
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* @return The opaque cookie which is used by the server to track its
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* position in the set of search results.
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*/
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public ByteString getCookie() {
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return cookie;
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}
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/**
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* {@inheritDoc}
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*/
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public String getOID() {
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return OID;
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}
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/**
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* Returns the requested page size when used in a request control from the
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* client, or an estimate of the result set size when used in a response
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* control from the server (may be 0, indicating that the server does not
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* know).
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*
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* @return The requested page size when used in a request control from the
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* client, or an estimate of the result set size when used in a
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* response control from the server.
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*/
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public int getSize() {
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return size;
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}
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/**
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* {@inheritDoc}
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*/
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public ByteString getValue() {
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final ByteStringBuilder buffer = new ByteStringBuilder();
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final ASN1Writer writer = ASN1.getWriter(buffer);
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try {
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writer.writeStartSequence();
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writer.writeInteger(size);
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writer.writeOctetString(cookie);
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writer.writeEndSequence();
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return buffer.toByteString();
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} catch (final IOException ioe) {
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// This should never happen unless there is a bug somewhere.
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throw new RuntimeException(ioe);
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}
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}
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/**
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* {@inheritDoc}
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*/
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public boolean hasValue() {
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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public boolean isCritical() {
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return isCritical;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String toString() {
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final StringBuilder builder = new StringBuilder();
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builder.append("SimplePagedResultsControl(oid=");
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builder.append(getOID());
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builder.append(", criticality=");
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builder.append(isCritical());
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builder.append(", size=");
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builder.append(size);
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builder.append(", cookie=");
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builder.append(cookie);
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builder.append(")");
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return builder.toString();
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}
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}
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