001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it 
010 * under the terms of the GNU Lesser General Public License as published by 
011 * the Free Software Foundation; either version 2.1 of the License, or 
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but 
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022 * USA.  
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * ----------------------
028 * ObjectDescription.java
029 * ----------------------
030 * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: ObjectDescription.java,v 1.3 2005/11/14 11:03:12 mungady Exp $
036 *
037 * Changes (from 19-Feb-2003)
038 * -------------------------
039 * 19-Feb-2003 : Added standard header and Javadocs (DG);
040 * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon
041 *
042 */
043
044package org.jfree.xml.factory.objects;
045
046import java.io.Serializable;
047import java.util.Iterator;
048
049import org.jfree.util.Configuration;
050
051/**
052 * An interface for object descriptions.
053 *
054 * @author Thomas Morgner
055 */
056public interface ObjectDescription extends Serializable {
057
058    /**
059     * Returns a parameter definition. If the parameter is invalid, this
060     * function returns null.
061     *
062     * @param name  the definition name.
063     *
064     * @return The parameter class or null, if the parameter is not defined.
065     */
066    public Class getParameterDefinition(String name);
067
068    /**
069     * Sets the value of a parameter.
070     *
071     * @param name  the parameter name.
072     * @param value  the parameter value.
073     */
074    public void setParameter(String name, Object value);
075
076    /**
077     * Returns the value of a parameter.
078     *
079     * @param name  the parameter name.
080     *
081     * @return The value.
082     */
083    public Object getParameter(String name);
084
085    /**
086     * Returns an iterator the provides access to the parameter names. This
087     * returns all _known_ parameter names, the object description may accept
088     * additional parameters.
089     *
090     * @return The iterator.
091     */
092    public Iterator getParameterNames();
093
094    /**
095     * Returns the object class.
096     *
097     * @return The Class.
098     */
099    public Class getObjectClass();
100
101    /**
102     * Creates an object based on the description.
103     *
104     * @return The object.
105     */
106    public Object createObject();
107
108    /**
109     * Returns a cloned instance of the object description. The contents
110     * of the parameter objects collection are cloned too, so that any
111     * already defined parameter value is copied to the new instance.
112     * <p>
113     * Parameter definitions are not cloned, as they are considered read-only.
114     * <p>
115     * The newly instantiated object description is not configured. If it
116     * need to be configured, then you have to call configure on it.
117     *
118     * @return A cloned instance.
119     */
120    public ObjectDescription getUnconfiguredInstance();
121
122    /**
123     * Returns a cloned instance of the object description. The contents
124     * of the parameter objects collection are cloned too, so that any
125     * already defined parameter value is copied to the new instance.
126     * <p>
127     * Parameter definitions are not cloned, as they are considered read-only.
128     *
129     * @return A cloned instance.
130     */
131    public ObjectDescription getInstance();
132
133    /**
134     * Sets the parameters of this description object to match the supplied object.
135     *
136     * @param o  the object.
137     *
138     * @throws ObjectFactoryException if there is a problem while reading the
139     * properties of the given object.
140     */
141    public void setParameterFromObject(Object o) throws ObjectFactoryException;
142
143
144    /**
145     * Configures this factory. The configuration contains several keys and
146     * their defined values. The given reference to the configuration object
147     * will remain valid until the report parsing or writing ends.
148     * <p>
149     * The configuration contents may change during the reporting.
150     *
151     * @param config the configuration, never null
152     */
153    public void configure(Configuration config);
154
155    /**
156     * Compares whether two object descriptions are equal.
157     *
158     * @param o the other object.
159     * @return true, if both object desciptions describe the same object, false otherwise.
160     */
161    public boolean equals (Object o);
162
163
164    /**
165     * Computes the hashCode for this ClassFactory. As equals() must be implemented,
166     * a corresponding hashCode() should be implemented as well.
167     *
168     * @return the hashcode.
169     */
170    public int hashCode();
171
172}