/*
 * 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.
 */
package org.forgerock.opendj.ldap.controls;

import static org.forgerock.opendj.ldap.CoreMessages.ERR_PERMISSIVE_MODIFY_CONTROL_BAD_OID;
import static org.forgerock.opendj.ldap.CoreMessages.ERR_PERMISSIVE_MODIFY_INVALID_CONTROL_VALUE;

import org.forgerock.i18n.LocalizableMessage;
import org.forgerock.opendj.ldap.ByteString;
import org.forgerock.opendj.ldap.DecodeException;
import org.forgerock.opendj.ldap.DecodeOptions;

import com.forgerock.opendj.util.Validator;

/**
 * The Microsoft defined permissive modify request control. The OID for this
 * control is 1.2.840.113556.1.4.1413, and it does not have a value.
 * <p>
 * This control can only be used with LDAP modify requests. It changes the
 * behavior of the modify operation as follows:
 * <ul>
 * <li>Attempts to add an attribute value which already exists will be ignored
 * and will not cause an
 * {@link org.forgerock.opendj.ldap.ResultCode#ATTRIBUTE_OR_VALUE_EXISTS
 * AttributeValueExists} error result to be returned.
 * <li>Attempts to delete an attribute value which does not exist will be
 * ignored and will not cause an
 * {@link org.forgerock.opendj.ldap.ResultCode#NO_SUCH_ATTRIBUTE
 * NoSuchAttribute} error result to be returned.
 * </ul>
 * In other words, a modify request {@code add} modification <i>ensures</i> that
 * the attribute contains the specified attribute value, and a {@code delete}
 * modification <i>ensures</i> that the attribute does not contain the specified
 * attribute value.
 *
 * <pre>
 * String groupDN = ...;
 * String memberDN = ...;
 * Connection connection = ...;
 *
 * // Add a member to a static group, telling the directory server not to
 * // complain if the member already belongs to the group.
 * ModifyRequest request = Requests.newModifyRequest(groupDN)
 *          .addControl(PermissiveModifyRequestControl.newControl(true))
 *          .addModification(ModificationType.ADD, "member", memberDN);
 * connection.modify(request);
 * </pre>
 */
public final class PermissiveModifyRequestControl implements Control {
    /**
     * The OID for the permissive modify request control.
     */
    public static final String OID = "1.2.840.113556.1.4.1413";

    private static final PermissiveModifyRequestControl CRITICAL_INSTANCE =
            new PermissiveModifyRequestControl(true);

    private static final PermissiveModifyRequestControl NONCRITICAL_INSTANCE =
            new PermissiveModifyRequestControl(false);

    /**
     * A decoder which can be used for decoding the permissive modify request
     * control.
     */
    public static final ControlDecoder<PermissiveModifyRequestControl> DECODER =
            new ControlDecoder<PermissiveModifyRequestControl>() {

                public PermissiveModifyRequestControl decodeControl(final Control control,
                        final DecodeOptions options) throws DecodeException {
                    Validator.ensureNotNull(control);

                    if (control instanceof PermissiveModifyRequestControl) {
                        return (PermissiveModifyRequestControl) control;
                    }

                    if (!control.getOID().equals(OID)) {
                        final LocalizableMessage message =
                                ERR_PERMISSIVE_MODIFY_CONTROL_BAD_OID.get(control.getOID(), OID);
                        throw DecodeException.error(message);
                    }

                    if (control.hasValue()) {
                        final LocalizableMessage message =
                                ERR_PERMISSIVE_MODIFY_INVALID_CONTROL_VALUE.get();
                        throw DecodeException.error(message);
                    }

                    return control.isCritical() ? CRITICAL_INSTANCE : NONCRITICAL_INSTANCE;
                }

                public String getOID() {
                    return OID;
                }
            };

    /**
     * Creates a new permissive modify request control having the provided
     * criticality.
     *
     * @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.
     * @return The new control.
     */
    public static PermissiveModifyRequestControl newControl(final boolean isCritical) {
        return isCritical ? CRITICAL_INSTANCE : NONCRITICAL_INSTANCE;
    }

    private final boolean isCritical;

    private PermissiveModifyRequestControl(final boolean isCritical) {
        this.isCritical = isCritical;
    }

    /**
     * {@inheritDoc}
     */
    public String getOID() {
        return OID;
    }

    /**
     * {@inheritDoc}
     */
    public ByteString getValue() {
        return null;
    }

    /**
     * {@inheritDoc}
     */
    public boolean hasValue() {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    public boolean isCritical() {
        return isCritical;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        final StringBuilder builder = new StringBuilder();
        builder.append("PermissiveModifyRequestControl(oid=");
        builder.append(getOID());
        builder.append(", criticality=");
        builder.append(isCritical());
        builder.append(")");
        return builder.toString();
    }

}