/*
 * 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 2008 Sun Microsystems, Inc.
 */
package org.opends.server.admin.condition;

import org.forgerock.opendj.ldap.ErrorResultException;
import org.opends.server.admin.AbstractManagedObjectDefinition;
import org.opends.server.admin.client.ManagedObject;
import org.opends.server.admin.client.ManagementContext;
import org.opends.server.admin.server.ServerManagedObject;
import org.opends.server.config.spi.ConfigException;

/**
 * This class consists exclusively of static methods that operate on or return
 * conditions.
 */
public final class Conditions {

    /**
     * A condition which always evaluates to <code>false</code>.
     */
    public static final Condition FALSE = new Condition() {

        /**
         * {@inheritDoc}
         */
        public boolean evaluate(ManagementContext context, ManagedObject<?> managedObject) throws ErrorResultException {
            return false;
        }

        /**
         * {@inheritDoc}
         */
        public boolean evaluate(ServerManagedObject<?> managedObject) throws ConfigException {
            return false;
        }

        /**
         * {@inheritDoc}
         */
        public void initialize(AbstractManagedObjectDefinition<?, ?> d) throws Exception {
            // No implementation required.
        }

    };

    /**
     * A condition which always evaluates to <code>true</code>.
     */
    public static final Condition TRUE = new Condition() {

        /**
         * {@inheritDoc}
         */
        public boolean evaluate(ManagementContext context, ManagedObject<?> managedObject) throws ErrorResultException {
            return true;
        }

        /**
         * {@inheritDoc}
         */
        public boolean evaluate(ServerManagedObject<?> managedObject) throws ConfigException {
            return true;
        }

        /**
         * {@inheritDoc}
         */
        public void initialize(AbstractManagedObjectDefinition<?, ?> d) throws Exception {
            // No implementation required.
        }

    };

    /**
     * Creates a condition which evaluates to <code>true</code> if and only if
     * all of its sub-conditions are <code>true</code>.
     *
     * @param conditions
     *            The sub-conditions which be combined using a logical AND.
     * @return Returns a condition which evaluates to <code>true</code> if and
     *         only if all of its sub-conditions are <code>true</code>.
     */
    public static Condition and(Condition... conditions) {
        return new ANDCondition(conditions);
    }

    /**
     * Creates a condition which evaluates to <code>true</code> if and only if a
     * property contains a particular value.
     *
     * @param propertyName
     *            The property name.
     * @param propertyStringValue
     *            The string representation of the required property value.
     * @return Returns a condition which evaluates to <code>true</code> if and
     *         only if a property contains a particular value.
     */
    public static Condition contains(String propertyName, String propertyStringValue) {
        return new ContainsCondition(propertyName, propertyStringValue);
    }

    /**
     * Creates a condition which evaluates to <code>false</code> if and only if
     * the first sub-condition evaluates to <code>true</code> and the second
     * sub-condition evaluates to <code>false</code>. This can be used to
     * represent if-then relationships.
     *
     * @param premise
     *            The sub-condition which, when <code>true</code> implies that
     *            the implication sub-condition must also be <code>true</code>.
     * @param implication
     *            The sub-condition which, must be <code>true</code> when the
     *            premise is <code>true</code>.
     * @return Returns a condition which evaluates to <code>false</code> if and
     *         only if the first sub-condition evaluates to <code>true</code>
     *         and the second sub-condition evaluates to <code>false</code>.
     */
    public static Condition implies(Condition premise, Condition implication) {
        return or(not(premise), implication);
    }

    /**
     * Creates a condition which evaluates to <code>true</code> if and only if a
     * particular property has any values specified.
     *
     * @param propertyName
     *            The property name.
     * @return Returns a condition which evaluates to <code>true</code> if and
     *         only if a particular property has any values specified.
     */
    public static Condition isPresent(String propertyName) {
        return new IsPresentCondition(propertyName);
    }

    /**
     * Creates a condition which evaluates to <code>true</code> if the
     * sub-condition is <code>false</code>, or <code>false</code> if the
     * sub-condition is <code>true</code>.
     *
     * @param condition
     *            The sub-condition which will be inverted.
     * @return Returns a condition which evaluates to <code>true</code> if the
     *         sub-condition is <code>false</code>, or <code>false</code> if the
     *         sub-condition is <code>true</code>.
     */
    public static Condition not(Condition condition) {
        return new NOTCondition(condition);
    }

    /**
     * Creates a condition which evaluates to <code>false</code> if and only if
     * all of its sub-conditions are <code>false</code>.
     *
     * @param conditions
     *            The sub-conditions which be combined using a logical OR.
     * @return Returns a condition which evaluates to <code>false</code> if and
     *         only if all of its sub-conditions are <code>false</code>.
     */
    public static Condition or(Condition... conditions) {
        return new ORCondition(conditions);
    }

    // Prevent instantiation.
    private Conditions() {
        // No implementation required.
    }

}