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