/* ===================================================
 * JCommon : a free general purpose Java class library
 * ===================================================
 *
 * Project Info:  http://www.jfree.org/jcommon/index.html
 * Project Lead:  David Gilbert (david.gilbert@object-refinery.com);
 *
 * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
 *
 * This library 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 library 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
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * ----------------------
 * ObjectDescription.java
 * ----------------------
 * (C)opyright 2003, by Thomas Morgner and Contributors.
 *
 * Original Author:  Thomas Morgner;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: ObjectDescription.java,v 1.8 2003/07/20 19:24:24 taqua Exp $
 *
 * Changes (from 19-Feb-2003)
 * -------------------------
 * 19-Feb-2003 : Added standard header and Javadocs (DG);
 * 29-Apr-2003 : Destilled from the JFreeReport project and moved into JCommon
 *
 */

package org.jfree.xml.factory.objects;

import java.util.Iterator;
import java.io.Serializable;

import org.jfree.util.Configuration;

/**
 * An interface for object descriptions.
 *
 * @author Thomas Morgner
 */
public interface ObjectDescription extends Serializable {

    /**
     * Returns a parameter definition. If the parameter is invalid, this
     * function returns null.
     *
     * @param name  the definition name.
     *
     * @return The parameter class or null, if the parameter is not defined.
     */
    public Class getParameterDefinition(String name);

    /**
     * Sets the value of a parameter.
     *
     * @param name  the parameter name.
     * @param value  the parameter value.
     */
    public void setParameter(String name, Object value);

    /**
     * Returns the value of a parameter.
     *
     * @param name  the parameter name.
     *
     * @return The value.
     */
    public Object getParameter(String name);

    /**
     * Returns an iterator the provides access to the parameter names. This
     * returns all _known_ parameter names, the object description may accept
     * additional parameters.
     *
     * @return The iterator.
     */
    public Iterator getParameterNames();

    /**
     * Returns the object class.
     *
     * @return The Class.
     */
    public Class getObjectClass();

    /**
     * Creates an object based on the description.
     *
     * @return The object.
     */
    public Object createObject();

    /**
     * Returns a cloned instance of the object description. The contents
     * of the parameter objects collection are cloned too, so that any
     * already defined parameter value is copied to the new instance.
     * <p>
     * Parameter definitions are not cloned, as they are considered read-only.
     * <p>
     * The newly instantiated object description is not configured. If it
     * need to be configured, then you have to call configure on it.
     *
     * @return A cloned instance.
     */
    public ObjectDescription getUnconfiguredInstance();

    /**
     * Returns a cloned instance of the object description. The contents
     * of the parameter objects collection are cloned too, so that any
     * already defined parameter value is copied to the new instance.
     * <p>
     * Parameter definitions are not cloned, as they are considered read-only.
     *
     * @return A cloned instance.
     */
    public ObjectDescription getInstance();

    /**
     * Sets the parameters of this description object to match the supplied object.
     *
     * @param o  the object.
     *
     * @throws ObjectFactoryException if there is a problem while reading the
     * properties of the given object.
     */
    public void setParameterFromObject(Object o) throws ObjectFactoryException;


    /**
     * Configures this factory. The configuration contains several keys and
     * their defined values. The given reference to the configuration object
     * will remain valid until the report parsing or writing ends.
     * <p>
     * The configuration contents may change during the reporting.
     *
     * @param config the configuration, never null
     */
    public void configure(Configuration config);

    /**
     * Compares whether two object descriptions are equal.
     *
     * @param o the other object.
     * @return true, if both object desciptions describe the same object, false otherwise.
     */
    public boolean equals (Object o);


}