AbstractScopedKey.java

/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.commons.scope;

import java.io.Serializable;


/**
 * The abstract scoped key should be subclasses to create scoped key.
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
public abstract class AbstractScopedKey implements Serializable {

    /** . */
    private final String scope;

    protected AbstractScopedKey() {
        String scope = ScopeManager.getCurrentScope();
        if (scope == null) {
            scope = "";
        }

        //
        this.scope = scope;
    }

    protected AbstractScopedKey(String scope) throws NullPointerException {
        if (scope == null) {
            throw new NullPointerException();
        }

        //
        this.scope = scope;
    }

    public final String getScope() {
        return scope;
    }

    /**
     * Returns the scope value hashCode.
     *
     * @return the hash code
     */
    @Override
    public int hashCode() {
        return scope.hashCode();
    }

    /**
     * Returns true when:
     * <ul>
     * <li>the obj argument has the same reference than this object</li>
     * <li>or the obj has class equality (<code>getClass().equals(obj.getClass())</code>) and scope equality</li>
     * </ul>
     *
     * Subclasses should override this method and call the super method to ensure that the objects are of the same class and
     * have the same scope. When this method returns true, the obj argument can be safely casted to the same sub class for
     * performing more state equality checks.
     */
    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj instanceof AbstractScopedKey) {
            AbstractScopedKey that = (AbstractScopedKey) obj;
            return getClass().equals(that.getClass()) && scope.equals(that.scope);
        }
        return false;
    }
}