/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.
 */
package org.apereo.portal.layout.dlm;

import javax.persistence.Cacheable;
import javax.persistence.Column;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.TableGenerator;
import javax.persistence.Version;
import org.apereo.portal.security.IPerson;
import org.dom4j.Element;
import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;

/**
 * @since 2.5
 */
@Entity
@Table(name = "UP_DLM_EVALUATOR")
@SequenceGenerator(
    name = "UP_DLM_EVALUATOR_GEN",
    sequenceName = "UP_DLM_EVALUATOR_SEQ",
    allocationSize = 1
)
@TableGenerator(
    name = "UP_DLM_EVALUATOR_GEN",
    pkColumnValue = "UP_DLM_EVALUATOR",
    allocationSize = 1
)
@Cacheable
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "EVALUATOR_TYPE")
public abstract class Evaluator {

    @Id
    @GeneratedValue(generator = "UP_DLM_EVALUATOR_GEN")
    @Column(name = "EVALUATOR_ID")
    private final long evaluatorId;

    @Version
    @Column(name = "ENTITY_VERSION")
    private final long entityVersion;

    public Evaluator() {
        evaluatorId = -1L;
        entityVersion = -1;
    }

    public abstract boolean isApplicable(IPerson person);

    /**
     * Serializes this {@link Evaluator} into the same XML format supported by dlm.xml. <b>NOTE:</b>
     * this method will only yield usable XML if invoked on an instance of {@link
     * FragmentDefinition}; all other subclasses will return only XML fragments.
     *
     * @param parent The XML structure (starting with <dlm:fragment>) so far
     */
    public abstract void toElement(Element parent);

    public abstract Class<? extends EvaluatorFactory> getFactoryClass();

    /**
     * Provides a one-line, human-readable description of the users who are members of the fragment
     * audience based on this {@link Evaluator}.
     *
     * @return A short description of what this {@link Evaluator} does
     */
    public abstract String getSummary();
}