owlapi-version5/api/src/main/java/org/semanticweb/owlapi/change/OWLOntologyChangeData.java
/* This file is part of the OWL API.
 * The contents of this file are subject to the LGPL License, Version 3.0.
 * Copyright 2014, The University of Manchester
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Alternatively, the contents of this file may be used under the terms of the Apache License, Version 2.0 in which case, the provisions of the Apache License Version 2.0 are applicable instead of those above.
 * Licensed 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
 * http://www.apache.org/licenses/LICENSE-2.0
 * 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.semanticweb.owlapi.change;

import java.io.Serializable;
import javax.annotation.Nullable;
import org.semanticweb.owlapi.model.HasSignature;
import org.semanticweb.owlapi.model.OWLOntology;
import org.semanticweb.owlapi.model.OWLOntologyChange;

/**
 * Represents an abstraction of the essential non-ontology data required by a
 * particular kind of {@link OWLOntologyChange}. There is a concrete subclass of
 * this class for each concrete class of {@link OWLOntologyChange}. <br>
 * Instances of this class are immutable.
 *
 * @author Matthew Horridge, Stanford University, Bio-Medical Informatics Research Group
 * @see org.semanticweb.owlapi.model.OWLOntologyChange#getChangeData()
 * @since 3.3
 */
public abstract class OWLOntologyChangeData implements HasSignature, Serializable {

    /**
     * Default constructor for serialization purposes.
     */
    protected OWLOntologyChangeData() {
        super();
    }

    /**
     * Accepts a visit from an {@link OWLOntologyChangeDataVisitor}.
     *
     * @param visitor The visitor
     * @param <R> The return type for visitor's visit methods.
     * @return The object returned by the visitor's visit methods.
     */
    public abstract <R> R accept(OWLOntologyChangeDataVisitor<R> visitor);

    /**
     * Creates an {@link OWLOntologyChange} object that pertains to the
     * specified {@code ontology}, which when applied to the specified ontology
     * enacts the change described by this info object.
     *
     * @param ontology The {@link OWLOntology} that the change should apply to.
     * @return An {@link OWLOntologyChange} object that applies to {@code ontology} and changes
     * {@code ontology} in a way that is consistent with this the information held in this {@code
     * OWLOntologyChangeData} object.
     **/
    public abstract OWLOntologyChange createOntologyChange(OWLOntology ontology);

    /**
     * @return a name for the object class
     */
    protected String getName() {
        return getClass().getSimpleName();
    }

    protected String getTemplate() {
        return getName() + "(%s)";
    }

    protected String toString(Object o) {
        return String.format(getTemplate(), o);
    }

    @Override
    public String toString() {
        return toString(getItem());
    }

    /**
     * @return the object this change is adding or removing
     */
    public abstract Object getItem();

    @Override
    public int hashCode() {
        return getClass().hashCode() + getItem().hashCode();
    }

    @Override
    public boolean equals(@Nullable Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!getClass().equals(obj.getClass())) {
            return false;
        }
        return getItem().equals(((OWLOntologyChangeData) obj).getItem());
    }
}
