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Java > Open Source Codes > com > jcorporate > expresso > core > dataobjects > DataTransferObject


1 /* ====================================================================
2  * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
3  *
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59  * <http://www.jcorporate.com/>.
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61  * Portions of this software are based upon other open source
62  * products and are subject to their respective licenses.
63  */
64
65 package com.jcorporate.expresso.core.dataobjects;
66
67 import java.io.Externalizable JavaDoc;
68 import java.io.IOException JavaDoc;
69 import java.util.HashMap JavaDoc;
70 import java.util.Map JavaDoc;
71
72 /**
73  * Basic HashMap wrapper for the Data Transfer Object pattern. The goal of this
74  * class is to provide efficient serialization over the wire of DBOBjects and
75  * or the up and coming DataObjects. By encapsulating the 'data guts' of the
76  * data objects into this class, routing programs that don't have to know anything
77  * about a particular instance of a DBObject/DataObject don't have to have any
78  * large code base installed on them.
79  * <p>The other advantage of DataTransferObject is serialization size. On
80  * tests conducted 3/17/04, the size of com.jcorporate.expresso.services.dbobj.MimeTypes
81  * was 1310 bytes. The size of the same item converted into a DataTransfer
82  * object was 293 bytes. For in-memory serialization alone, this translates
83  * to twice as fast. For slower connections such as sockets, this speed translation
84  * will be more pronounced.</p>
85  *
86  * @author Michael Rimov
87  * @since Expresso 5.0
88  */
89
90 public final class DataTransferObject implements Externalizable JavaDoc {
91     transient private static final String JavaDoc EMPTY_STRING = "";
92
93     private java.util.HashMap JavaDoc tableFields = new HashMap JavaDoc();
94     private String JavaDoc dataContext;
95     private String JavaDoc objectClassName;
96
97
98     public DataTransferObject() {
99     }
100
101
102     /**
103      * Optimized Deserialization
104      *
105      * @param ois The Object Input object
106      * @throws java.lang.ClassNotFoundException
107      * for reading subobjects
108      * @throws IOException upon I/O error
109      */
110     public void readExternal(java.io.ObjectInput JavaDoc ois) throws ClassNotFoundException JavaDoc, IOException JavaDoc {
111         tableFields = (HashMap JavaDoc) ois.readObject();
112         dataContext = ois.readUTF();
113         objectClassName = ois.readUTF();
114     }
115
116
117     /**
118      * Optimized Serialization implementation that does not utilize any
119      * reflection
120      *
121      * @param oos The Object Output Stream
122      */
123     public void writeExternal(java.io.ObjectOutput JavaDoc oos) throws IOException JavaDoc {
124         oos.writeObject(tableFields);
125         if (dataContext == null) {
126             oos.writeUTF(EMPTY_STRING);
127         } else {
128             oos.writeUTF(dataContext);
129         }
130
131         if (objectClassName == null) {
132             oos.writeUTF(EMPTY_STRING);
133         } else {
134             oos.writeUTF(objectClassName);
135         }
136
137     }
138
139
140     /**
141      * Sets the data fields in bulk. Does not perform a data copy
142      * unless the passed in type is not a HashMap
143      *
144      * @param tableFields the new set of table fields to use
145      */
146     public void setTableFields(Map JavaDoc tableFields) {
147         if (tableFields instanceof HashMap JavaDoc) {
148             this.tableFields = (HashMap JavaDoc) tableFields;
149         } else {
150             this.tableFields = new HashMap JavaDoc(tableFields);
151         }
152     }
153
154     /**
155      * Gets the table fields in bulk
156      *
157      * @return java.util.HashMap
158      */
159     public java.util.Map JavaDoc getTableFields() {
160         return tableFields;
161     }
162
163     /**
164      * @param dataContext The new data context to use
165      */
166     public void setDataContext(String JavaDoc dataContext) {
167         this.dataContext = dataContext;
168     }
169
170     /**
171      * @return the currently set data context.
172      */
173     public String JavaDoc getDataContext() {
174         return dataContext;
175     }
176
177     /**
178      * Sets the classname of the DataObject we're attached to so that we can
179      * instantiate it at the far end of the wire.
180      *
181      * @param objectClassName the full classname
182      */
183     public void setObjectClassName(String JavaDoc objectClassName) {
184         this.objectClassName = objectClassName;
185     }
186
187     public String JavaDoc getObjectClassName() {
188         return objectClassName;
189     }
190
191 }
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