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/*
 * Copyright 2007-2024 Ping Identity Corporation
 * All Rights Reserved.
 */
/*
 * Copyright 2007-2024 Ping Identity Corporation
 *
 * 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.
 */
/*
 * Copyright (C) 2007-2024 Ping Identity Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (GPLv2 only)
 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
 * as published by the Free Software Foundation.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see .
 */
package com.unboundid.ldap.sdk.controls;



import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import com.unboundid.asn1.ASN1Element;
import com.unboundid.asn1.ASN1Exception;
import com.unboundid.asn1.ASN1Integer;
import com.unboundid.asn1.ASN1OctetString;
import com.unboundid.asn1.ASN1Sequence;
import com.unboundid.ldap.sdk.Control;
import com.unboundid.ldap.sdk.DecodeableControl;
import com.unboundid.ldap.sdk.JSONControlDecodeHelper;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.ResultCode;
import com.unboundid.ldap.sdk.SearchResult;
import com.unboundid.util.Base64;
import com.unboundid.util.Debug;
import com.unboundid.util.NotMutable;
import com.unboundid.util.NotNull;
import com.unboundid.util.Nullable;
import com.unboundid.util.ThreadSafety;
import com.unboundid.util.ThreadSafetyLevel;
import com.unboundid.util.json.JSONField;
import com.unboundid.util.json.JSONNumber;
import com.unboundid.util.json.JSONObject;
import com.unboundid.util.json.JSONString;
import com.unboundid.util.json.JSONValue;

import static com.unboundid.ldap.sdk.controls.ControlMessages.*;



/**
 * This class provides an implementation of the simple paged results control as
 * defined in RFC 2696.  It
 * allows the client to iterate through a potentially large set of search
 * results in subsets of a specified number of entries (i.e., "pages").
 * 

* The same control encoding is used for both the request control sent by * clients and the response control returned by the server. It may contain * two elements: *
    *
  • Size -- In a request control, this provides the requested page size, * which is the maximum number of entries that the server should return * in the next iteration of the search. In a response control, it is an * estimate of the total number of entries that match the search * criteria.
  • *
  • Cookie -- A token which is used by the server to keep track of its * position in the set of search results. The first request sent by the * client should not include a cookie, and the last response sent by the * server should not include a cookie. For all other intermediate search * requests and responses, the server will include a cookie value in its * response that the client should include in its next request.
  • *
* When the client wishes to use the paged results control, the first search * request should include a version of the paged results request control that * was created with a requested page size but no cookie. The corresponding * response from the server will include a version of the paged results control * that may include an estimate of the total number of matching entries, and * may also include a cookie. The client should include this cookie in the * next request (with the same set of search criteria) to retrieve the next page * of results. This process should continue until the response control returned * by the server does not include a cookie, which indicates that the end of the * result set has been reached. *

* Note that the simple paged results control is similar to the * {@link VirtualListViewRequestControl} in that both allow the client to * request that only a portion of the result set be returned at any one time. * However, there are significant differences between them, including: *
    *
  • In order to use the virtual list view request control, it is also * necessary to use the {@link ServerSideSortRequestControl} to ensure * that the entries are sorted. This is not a requirement for the * simple paged results control.
  • *
  • The simple paged results control may only be used to iterate * sequentially through the set of search results. The virtual list view * control can retrieve pages out of order, can retrieve overlapping * pages, and can re-request pages that it had already retrieved.
  • *
*

Example

* The following example demonstrates the use of the simple paged results * control. It will iterate through all users, retrieving up to 10 entries at a * time: *
 * // Perform a search to retrieve all users in the server, but only retrieving
 * // ten at a time.
 * int numSearches = 0;
 * int totalEntriesReturned = 0;
 * SearchRequest searchRequest = new SearchRequest("dc=example,dc=com",
 *      SearchScope.SUB, Filter.createEqualityFilter("objectClass", "person"));
 * ASN1OctetString resumeCookie = null;
 * while (true)
 * {
 *   searchRequest.setControls(
 *        new SimplePagedResultsControl(10, resumeCookie));
 *   SearchResult searchResult = connection.search(searchRequest);
 *   numSearches++;
 *   totalEntriesReturned += searchResult.getEntryCount();
 *   for (SearchResultEntry e : searchResult.getSearchEntries())
 *   {
 *     // Do something with each entry...
 *   }
 *
 *   LDAPTestUtils.assertHasControl(searchResult,
 *        SimplePagedResultsControl.PAGED_RESULTS_OID);
 *   SimplePagedResultsControl responseControl =
 *        SimplePagedResultsControl.get(searchResult);
 *   if (responseControl.moreResultsToReturn())
 *   {
 *     // The resume cookie can be included in the simple paged results
 *     // control included in the next search to get the next page of results.
 *     resumeCookie = responseControl.getCookie();
 *   }
 *   else
 *   {
 *     break;
 *   }
 * }
 * 
*/ @NotMutable() @ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE) public final class SimplePagedResultsControl extends Control implements DecodeableControl { /** * The OID (1.2.840.113556.1.4.319) for the paged results control. */ @NotNull public static final String PAGED_RESULTS_OID = "1.2.840.113556.1.4.319"; /** * The name of the field used to hold the cookie in the JSON representation of * this control. */ @NotNull private static final String JSON_FIELD_COOKIE = "cookie"; /** * The name of the field used to hold the size in the JSON representation of * this control. */ @NotNull private static final String JSON_FIELD_SIZE = "size"; /** * The serial version UID for this serializable class. */ private static final long serialVersionUID = 2186787148024999291L; // The encoded cookie returned from the server (for a response control) or // that should be included in the next request to the server (for a request // control). @NotNull private final ASN1OctetString cookie; // The maximum requested page size (for a request control), or the estimated // total result set size (for a response control). private final int size; /** * Creates a new empty control instance that is intended to be used only for * decoding controls via the {@code DecodeableControl} interface. */ SimplePagedResultsControl() { size = 0; cookie = new ASN1OctetString(); } /** * Creates a new paged results control with the specified page size. This * version of the constructor should only be used when creating the first * search as part of the set of paged results. Subsequent searches to * retrieve additional pages should use the response control returned by the * server in their next request, until the response control returned by the * server does not include a cookie. * * @param pageSize The maximum number of entries that the server should * return in the first page. */ public SimplePagedResultsControl(final int pageSize) { super(PAGED_RESULTS_OID, false, encodeValue(pageSize, null)); size = pageSize; cookie = new ASN1OctetString(); } /** * Creates a new paged results control with the specified page size. This * version of the constructor should only be used when creating the first * search as part of the set of paged results. Subsequent searches to * retrieve additional pages should use the response control returned by the * server in their next request, until the response control returned by the * server does not include a cookie. * * @param pageSize The maximum number of entries that the server should * return in the first page. * @param isCritical Indicates whether this control should be marked * critical. */ public SimplePagedResultsControl(final int pageSize, final boolean isCritical) { super(PAGED_RESULTS_OID, isCritical, encodeValue(pageSize, null)); size = pageSize; cookie = new ASN1OctetString(); } /** * Creates a new paged results control with the specified page size and the * provided cookie. This version of the constructor should be used to * continue iterating through an existing set of results, but potentially * using a different page size. * * @param pageSize The maximum number of entries that the server should * return in the next page of the results. * @param cookie The cookie provided by the server after returning the * previous page of results, or {@code null} if this request * will retrieve the first page of results. */ public SimplePagedResultsControl(final int pageSize, @Nullable final ASN1OctetString cookie) { super(PAGED_RESULTS_OID, false, encodeValue(pageSize, cookie)); size = pageSize; if (cookie == null) { this.cookie = new ASN1OctetString(); } else { this.cookie = cookie; } } /** * Creates a new paged results control with the specified page size and the * provided cookie. This version of the constructor should be used to * continue iterating through an existing set of results, but potentially * using a different page size. * * @param pageSize The maximum number of entries that the server should * return in the first page. * @param cookie The cookie provided by the server after returning the * previous page of results, or {@code null} if this * request will retrieve the first page of results. * @param isCritical Indicates whether this control should be marked * critical. */ public SimplePagedResultsControl(final int pageSize, @Nullable final ASN1OctetString cookie, final boolean isCritical) { super(PAGED_RESULTS_OID, isCritical, encodeValue(pageSize, cookie)); size = pageSize; if (cookie == null) { this.cookie = new ASN1OctetString(); } else { this.cookie = cookie; } } /** * Creates a new paged results control from the control with the provided set * of information. This should be used to decode the paged results response * control returned by the server with a page of results. * * @param oid The OID for the control. * @param isCritical Indicates whether the control should be marked * critical. * @param value The encoded value for the control. This may be * {@code null} if no value was provided. * * @throws LDAPException If the provided control cannot be decoded as a * simple paged results control. */ public SimplePagedResultsControl(@NotNull final String oid, final boolean isCritical, @Nullable final ASN1OctetString value) throws LDAPException { super(oid, isCritical, value); if (value == null) { throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_NO_VALUE.get()); } final ASN1Sequence valueSequence; try { final ASN1Element valueElement = ASN1Element.decode(value.getValue()); valueSequence = ASN1Sequence.decodeAsSequence(valueElement); } catch (final ASN1Exception ae) { Debug.debugException(ae); throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_VALUE_NOT_SEQUENCE.get(ae), ae); } final ASN1Element[] valueElements = valueSequence.elements(); if (valueElements.length != 2) { throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_INVALID_ELEMENT_COUNT.get( valueElements.length)); } try { size = ASN1Integer.decodeAsInteger(valueElements[0]).intValue(); } catch (final ASN1Exception ae) { Debug.debugException(ae); throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_FIRST_NOT_INTEGER.get(ae), ae); } cookie = ASN1OctetString.decodeAsOctetString(valueElements[1]); } /** * {@inheritDoc} */ @Override() @NotNull() public SimplePagedResultsControl decodeControl(@NotNull final String oid, final boolean isCritical, @Nullable final ASN1OctetString value) throws LDAPException { return new SimplePagedResultsControl(oid, isCritical, value); } /** * Extracts a simple paged results response control from the provided result. * * @param result The result from which to retrieve the simple paged results * response control. * * @return The simple paged results response control contained in the * provided result, or {@code null} if the result did not contain a * simple paged results response control. * * @throws LDAPException If a problem is encountered while attempting to * decode the simple paged results response control * contained in the provided result. */ @Nullable() public static SimplePagedResultsControl get( @NotNull final SearchResult result) throws LDAPException { final Control c = result.getResponseControl(PAGED_RESULTS_OID); if (c == null) { return null; } if (c instanceof SimplePagedResultsControl) { return (SimplePagedResultsControl) c; } else { return new SimplePagedResultsControl(c.getOID(), c.isCritical(), c.getValue()); } } /** * Encodes the provided information into an octet string that can be used as * the value for this control. * * @param pageSize The maximum number of entries that the server should * return in the next page of the results. * @param cookie The cookie provided by the server after returning the * previous page of results, or {@code null} if this request * will retrieve the first page of results. * * @return An ASN.1 octet string that can be used as the value for this * control. */ @NotNull() private static ASN1OctetString encodeValue(final int pageSize, @Nullable final ASN1OctetString cookie) { final ASN1Element[] valueElements; if (cookie == null) { valueElements = new ASN1Element[] { new ASN1Integer(pageSize), new ASN1OctetString() }; } else { valueElements = new ASN1Element[] { new ASN1Integer(pageSize), cookie }; } return new ASN1OctetString(new ASN1Sequence(valueElements).encode()); } /** * Retrieves the size for this paged results control. For a request control, * it may be used to specify the number of entries that should be included in * the next page of results. For a response control, it may be used to * specify the estimated number of entries in the complete result set. * * @return The size for this paged results control. */ public int getSize() { return size; } /** * Retrieves the cookie for this control, which may be used in a subsequent * request to resume reading entries from the next page of results. The * value should have a length of zero when used to retrieve the first page of * results for a given search, and also in the response from the server when * there are no more entries to send. It should be non-empty for all other * conditions. * * @return The cookie for this control, or an empty cookie (with a value * length of zero) if there is none. */ @NotNull() public ASN1OctetString getCookie() { return cookie; } /** * Indicates whether there are more results to return as part of this search. * * @return {@code true} if there are more results to return, or * {@code false} if not. */ public boolean moreResultsToReturn() { return (cookie.getValue().length > 0); } /** * {@inheritDoc} */ @Override() @NotNull() public String getControlName() { return INFO_CONTROL_NAME_PAGED_RESULTS.get(); } /** * Retrieves a representation of this simple paged results control as a JSON * object. The JSON object uses the following fields: *
    *
  • * {@code oid} -- A mandatory string field whose value is the object * identifier for this control. For the simple paged results control, the * OID is "1.2.840.113556.1.4.319". *
  • *
  • * {@code control-name} -- An optional string field whose value is a * human-readable name for this control. This field is only intended for * descriptive purposes, and when decoding a control, the {@code oid} * field should be used to identify the type of control. *
  • *
  • * {@code criticality} -- A mandatory Boolean field used to indicate * whether this control is considered critical. *
  • *
  • * {@code value-base64} -- An optional string field whose value is a * base64-encoded representation of the raw value for this simple paged * results control. Exactly one of the {@code value-base64} and * {@code value-json} fields must be present. *
  • *
  • * {@code value-json} -- An optional JSON object field whose value is a * user-friendly representation of the value for this simple paged results * control. Exactly one of the {@code value-base64} and * {@code value-json} fields must be present, and if the * {@code value-json} field is used, then it will use the following * fields: *
      *
    • * {@code size} -- A mandatory integer field. When used in a request * control, this represents the maximum number of entries that should * be returned in the next page of results. When used in a response * control, it provides an estimate of the total number of entries * across all pages of the result set. *
    • *
    • * {@code cookie} -- An optional string field. When used in a request * control, this should be empty when requesting the first page of * results, and the value of the {@code cookie} field returned in the * response control from the previous page of results. For a response * control, this will be non-empty for all pages except the last page * of results. The cookie value used in the JSON representation of * the control will be a base64-encoded representation of the raw * cookie value that would be used in the LDAP representation of the * control, and it must be treated as an opaque blob by the client. *
    • *
    *
  • *
* * @return A JSON object that contains a representation of this control. */ @Override() @NotNull() public JSONObject toJSONControl() { final Map valueFields = new LinkedHashMap<>(); valueFields.put(JSON_FIELD_SIZE, new JSONNumber(size)); final byte[] cookieBytes = cookie.getValue(); if (cookieBytes.length > 0) { valueFields.put(JSON_FIELD_COOKIE, new JSONString(Base64.encode(cookieBytes))); } return new JSONObject( new JSONField(JSONControlDecodeHelper.JSON_FIELD_OID, PAGED_RESULTS_OID), new JSONField(JSONControlDecodeHelper.JSON_FIELD_CONTROL_NAME, INFO_CONTROL_NAME_PAGED_RESULTS.get()), new JSONField(JSONControlDecodeHelper.JSON_FIELD_CRITICALITY, isCritical()), new JSONField(JSONControlDecodeHelper.JSON_FIELD_VALUE_JSON, new JSONObject(valueFields))); } /** * Attempts to decode the provided object as a JSON representation of a * simple paged results control. * * @param controlObject The JSON object to be decoded. It must not be * {@code null}. * @param strict Indicates whether to use strict mode when decoding * the provided JSON object. If this is {@code true}, * then this method will throw an exception if the * provided JSON object contains any unrecognized * fields. If this is {@code false}, then unrecognized * fields will be ignored. * * @return The simple paged results control that was decoded from * the provided JSON object. * * @throws LDAPException If the provided JSON object cannot be parsed as a * valid simple paged results control. */ @NotNull() public static SimplePagedResultsControl decodeJSONControl( @NotNull final JSONObject controlObject, final boolean strict) throws LDAPException { final JSONControlDecodeHelper jsonControl = new JSONControlDecodeHelper( controlObject, strict, true, true); final ASN1OctetString rawValue = jsonControl.getRawValue(); if (rawValue != null) { return new SimplePagedResultsControl(jsonControl.getOID(), jsonControl.getCriticality(), rawValue); } final JSONObject valueObject = jsonControl.getValueObject(); final Integer pageSize = valueObject.getFieldAsInteger(JSON_FIELD_SIZE); if (pageSize == null) { throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_JSON_MISSING_PAGE_SIZE.get( controlObject.toSingleLineString(), JSON_FIELD_SIZE)); } final ASN1OctetString cookie; final String cookieBase64 = valueObject.getFieldAsString(JSON_FIELD_COOKIE); if ((cookieBase64 == null) || cookieBase64.isEmpty()) { cookie = new ASN1OctetString(); } else { try { cookie = new ASN1OctetString(Base64.decode(cookieBase64)); } catch (final Exception e) { Debug.debugException(e); throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_JSON_COOKIE_NOT_BASE64.get( controlObject.toSingleLineString(), JSON_FIELD_COOKIE), e); } } if (strict) { final List unrecognizedFields = JSONControlDecodeHelper.getControlObjectUnexpectedFields( valueObject, JSON_FIELD_SIZE, JSON_FIELD_COOKIE); if (! unrecognizedFields.isEmpty()) { throw new LDAPException(ResultCode.DECODING_ERROR, ERR_PAGED_RESULTS_JSON_UNRECOGNIZED_FIELD.get( controlObject.toSingleLineString(), unrecognizedFields.get(0))); } } return new SimplePagedResultsControl(pageSize, cookie, jsonControl.getCriticality()); } /** * {@inheritDoc} */ @Override() public void toString(@NotNull final StringBuilder buffer) { buffer.append("SimplePagedResultsControl(pageSize="); buffer.append(size); buffer.append(", isCritical="); buffer.append(isCritical()); buffer.append(')'); } }




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