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package javax.naming.ldap;

import java.io.IOException;
import com.sun.jndi.ldap.Ber;
import com.sun.jndi.ldap.BerEncoder;

Requests that the results of a search operation be sorted by the LDAP server before being returned. The sort criteria are specified using an ordered list of one or more sort keys, with associated sort parameters. Search results are sorted at the LDAP server according to the parameters supplied in the sort control and then returned to the requestor. If sorting is not supported at the server (and the sort control is marked as critical) then the search operation is not performed and an error is returned.

The following code sample shows how the class may be used:


    // Open an LDAP association
    LdapContext ctx = new InitialLdapContext();
    // Activate sorting
    String sortKey = "cn";
    ctx.setRequestControls(new Control[]{
        new SortControl(sortKey, Control.CRITICAL) });
    // Perform a search
    NamingEnumeration results =
        ctx.search("", "(objectclass=*)", new SearchControls());
    // Iterate over search results
    while (results != null && results.hasMore()) {
        // Display an entry
        SearchResult entry = (SearchResult)results.next();
        System.out.println(entry.getName());
        System.out.println(entry.getAttributes());
        // Handle the entry's response controls (if any)
        if (entry instanceof HasControls) {
            // ((HasControls)entry).getControls();
        }
    }
    // Examine the sort control response
    Control[] controls = ctx.getResponseControls();
    if (controls != null) {
        for (int i = 0; i < controls.length; i++) {
            if (controls[i] instanceof SortResponseControl) {
                SortResponseControl src = (SortResponseControl)controls[i];
                if (! src.isSorted()) {
                    throw src.getException();
                }
            } else {
                // Handle other response controls (if any)
            }
        }
    }
    // Close the LDAP association
    ctx.close();
    ...

This class implements the LDAPv3 Request Control for server-side sorting as defined in RFC 2891. The control's value has the following ASN.1 definition:

    SortKeyList ::= SEQUENCE OF SEQUENCE {
        attributeType     AttributeDescription,
        orderingRule  [0] MatchingRuleId OPTIONAL,
        reverseOrder  [1] BOOLEAN DEFAULT FALSE }
Author:Vincent Ryan
See Also:
Since:1.5
/** * Requests that the results of a search operation be sorted by the LDAP server * before being returned. * The sort criteria are specified using an ordered list of one or more sort * keys, with associated sort parameters. * Search results are sorted at the LDAP server according to the parameters * supplied in the sort control and then returned to the requestor. If sorting * is not supported at the server (and the sort control is marked as critical) * then the search operation is not performed and an error is returned. * <p> * The following code sample shows how the class may be used: * <pre>{@code * * // Open an LDAP association * LdapContext ctx = new InitialLdapContext(); * * // Activate sorting * String sortKey = "cn"; * ctx.setRequestControls(new Control[]{ * new SortControl(sortKey, Control.CRITICAL) }); * * // Perform a search * NamingEnumeration results = * ctx.search("", "(objectclass=*)", new SearchControls()); * * // Iterate over search results * while (results != null && results.hasMore()) { * // Display an entry * SearchResult entry = (SearchResult)results.next(); * System.out.println(entry.getName()); * System.out.println(entry.getAttributes()); * * // Handle the entry's response controls (if any) * if (entry instanceof HasControls) { * // ((HasControls)entry).getControls(); * } * } * // Examine the sort control response * Control[] controls = ctx.getResponseControls(); * if (controls != null) { * for (int i = 0; i < controls.length; i++) { * if (controls[i] instanceof SortResponseControl) { * SortResponseControl src = (SortResponseControl)controls[i]; * if (! src.isSorted()) { * throw src.getException(); * } * } else { * // Handle other response controls (if any) * } * } * } * * // Close the LDAP association * ctx.close(); * ... * * }</pre> * <p> * This class implements the LDAPv3 Request Control for server-side sorting * as defined in * <a href="http://www.ietf.org/rfc/rfc2891.txt">RFC 2891</a>. * * The control's value has the following ASN.1 definition: * <pre> * * SortKeyList ::= SEQUENCE OF SEQUENCE { * attributeType AttributeDescription, * orderingRule [0] MatchingRuleId OPTIONAL, * reverseOrder [1] BOOLEAN DEFAULT FALSE } * * </pre> * * @since 1.5 * @see SortKey * @see SortResponseControl * @author Vincent Ryan */
final public class SortControl extends BasicControl {
The server-side sort control's assigned object identifier is 1.2.840.113556.1.4.473.
/** * The server-side sort control's assigned object identifier * is 1.2.840.113556.1.4.473. */
public static final String OID = "1.2.840.113556.1.4.473"; private static final long serialVersionUID = -1965961680233330744L;
Constructs a control to sort on a single attribute in ascending order. Sorting will be performed using the ordering matching rule defined for use with the specified attribute.
Params:
  • sortBy – An attribute ID to sort by.
  • criticality – If true then the server must honor the control and return the search results sorted as requested or refuse to perform the search. If false, then the server need not honor the control.
Throws:
  • IOException – If an error was encountered while encoding the supplied arguments into a control.
/** * Constructs a control to sort on a single attribute in ascending order. * Sorting will be performed using the ordering matching rule defined * for use with the specified attribute. * * @param sortBy An attribute ID to sort by. * @param criticality If true then the server must honor the control * and return the search results sorted as * requested or refuse to perform the search. * If false, then the server need not honor the * control. * @exception IOException If an error was encountered while encoding the * supplied arguments into a control. */
public SortControl(String sortBy, boolean criticality) throws IOException { super(OID, criticality, null); super.value = setEncodedValue(new SortKey[]{ new SortKey(sortBy) }); }
Constructs a control to sort on a list of attributes in ascending order. Sorting will be performed using the ordering matching rule defined for use with each of the specified attributes.
Params:
  • sortBy – A non-null list of attribute IDs to sort by. The list is in order of highest to lowest sort key precedence.
  • criticality – If true then the server must honor the control and return the search results sorted as requested or refuse to perform the search. If false, then the server need not honor the control.
Throws:
  • IOException – If an error was encountered while encoding the supplied arguments into a control.
/** * Constructs a control to sort on a list of attributes in ascending order. * Sorting will be performed using the ordering matching rule defined * for use with each of the specified attributes. * * @param sortBy A non-null list of attribute IDs to sort by. * The list is in order of highest to lowest sort key * precedence. * @param criticality If true then the server must honor the control * and return the search results sorted as * requested or refuse to perform the search. * If false, then the server need not honor the * control. * @exception IOException If an error was encountered while encoding the * supplied arguments into a control. */
public SortControl(String[] sortBy, boolean criticality) throws IOException { super(OID, criticality, null); SortKey[] sortKeys = new SortKey[sortBy.length]; for (int i = 0; i < sortBy.length; i++) { sortKeys[i] = new SortKey(sortBy[i]); } super.value = setEncodedValue(sortKeys); }
Constructs a control to sort on a list of sort keys. Each sort key specifies the sort order and ordering matching rule to use.
Params:
  • sortBy – A non-null list of keys to sort by. The list is in order of highest to lowest sort key precedence.
  • criticality – If true then the server must honor the control and return the search results sorted as requested or refuse to perform the search. If false, then the server need not honor the control.
Throws:
  • IOException – If an error was encountered while encoding the supplied arguments into a control.
/** * Constructs a control to sort on a list of sort keys. * Each sort key specifies the sort order and ordering matching rule to use. * * @param sortBy A non-null list of keys to sort by. * The list is in order of highest to lowest sort key * precedence. * @param criticality If true then the server must honor the control * and return the search results sorted as * requested or refuse to perform the search. * If false, then the server need not honor the * control. * @exception IOException If an error was encountered while encoding the * supplied arguments into a control. */
public SortControl(SortKey[] sortBy, boolean criticality) throws IOException { super(OID, criticality, null); super.value = setEncodedValue(sortBy); } /* * Encodes the sort control's value using ASN.1 BER. * The result includes the BER tag and length for the control's value but * does not include the control's object identifier and criticality setting. * * @param sortKeys A non-null list of keys to sort by. * @return A possibly null byte array representing the ASN.1 BER encoded * value of the sort control. * @exception IOException If a BER encoding error occurs. */ private byte[] setEncodedValue(SortKey[] sortKeys) throws IOException { // build the ASN.1 BER encoding BerEncoder ber = new BerEncoder(30 * sortKeys.length + 10); String matchingRule; ber.beginSeq(Ber.ASN_SEQUENCE | Ber.ASN_CONSTRUCTOR); for (int i = 0; i < sortKeys.length; i++) { ber.beginSeq(Ber.ASN_SEQUENCE | Ber.ASN_CONSTRUCTOR); ber.encodeString(sortKeys[i].getAttributeID(), true); // v3 if ((matchingRule = sortKeys[i].getMatchingRuleID()) != null) { ber.encodeString(matchingRule, (Ber.ASN_CONTEXT | 0), true); } if (! sortKeys[i].isAscending()) { ber.encodeBoolean(true, (Ber.ASN_CONTEXT | 1)); } ber.endSeq(); } ber.endSeq(); return ber.getTrimmedBuf(); } }