001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018
019package org.apache.commons.beanutils;
020
021
022import java.io.IOException;
023import java.io.Serializable;
024import java.io.ObjectOutputStream;
025import java.io.ObjectInputStream;
026import java.io.StreamCorruptedException;
027import java.util.List;
028import java.util.Map;
029
030
031/**
032 * <p>The metadata describing an individual property of a DynaBean.</p>
033 *
034 * <p>The meta contains an <em>optional</em> content type property ({@link #getContentType})
035 * for use by mapped and iterated properties. 
036 * A mapped or iterated property may choose to indicate the type it expects.
037 * The DynaBean implementation may choose to enforce this type on its entries.
038 * Alternatively, an implementatin may choose to ignore this property.
039 * All keys for maps must be of type String so no meta data is needed for map keys.</p>
040 *
041 * @author Craig R. McClanahan
042 * @version $Revision: 926529 $ $Date: 2010-03-23 11:44:24 +0000 (Tue, 23 Mar 2010) $
043 */
044
045public class DynaProperty implements Serializable {
046
047    // ----------------------------------------------------------- Constants
048    
049    /*
050     * There are issues with serializing primitive class types on certain JVM versions
051     * (including java 1.3).
052     * This class uses a custom serialization implementation that writes an integer
053     * for these primitive class.
054     * This list of constants are the ones used in serialization.
055     * If these values are changed, then older versions will no longer be read correctly
056     */
057    private static final int BOOLEAN_TYPE = 1;
058    private static final int BYTE_TYPE = 2;
059    private static final int CHAR_TYPE = 3;
060    private static final int DOUBLE_TYPE = 4;
061    private static final int FLOAT_TYPE = 5;
062    private static final int INT_TYPE = 6;
063    private static final int LONG_TYPE = 7;
064    private static final int SHORT_TYPE = 8;
065    
066
067    // ----------------------------------------------------------- Constructors
068
069
070    /**
071     * Construct a property that accepts any data type.
072     *
073     * @param name Name of the property being described
074     */
075    public DynaProperty(String name) {
076
077        this(name, Object.class);
078
079    }
080
081
082    /**
083     * Construct a property of the specified data type.
084     *
085     * @param name Name of the property being described
086     * @param type Java class representing the property data type
087     */
088    public DynaProperty(String name, Class type) {
089
090        super();
091        this.name = name;
092        this.type = type;
093        if (type != null && type.isArray()) {
094            this.contentType = type.getComponentType();
095        }
096
097    }
098    
099    /**
100     * Construct an indexed or mapped <code>DynaProperty</code> that supports (pseudo)-introspection
101     * of the content type.
102     *
103     * @param name Name of the property being described
104     * @param type Java class representing the property data type
105     * @param contentType Class that all indexed or mapped elements are instances of
106     */
107    public DynaProperty(String name, Class type, Class contentType) {
108
109        super();
110        this.name = name;
111        this.type = type;
112        this.contentType = contentType;
113        
114    }
115
116    // ------------------------------------------------------------- Properties
117
118    /** Property name */
119    protected String name = null;
120    /**
121     * Get the name of this property.
122     * @return the name of the property
123     */
124    public String getName() {
125        return (this.name);
126    }
127    
128    /** Property type */
129    protected transient Class type = null;
130    /**
131     * <p>Gets the Java class representing the data type of the underlying property
132     * values.</p>
133     * 
134     * <p>There are issues with serializing primitive class types on certain JVM versions
135     * (including java 1.3).
136     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
137     * 
138     * <p><strong>Please leave this field as <code>transient</code></strong></p>
139     *
140     * @return the property type
141     */
142    public Class getType() {
143        return (this.type);
144    }
145    
146    
147    /** The <em>(optional)</em> type of content elements for indexed <code>DynaProperty</code> */
148    protected transient Class contentType;
149    /**
150     * Gets the <em>(optional)</em> type of the indexed content for <code>DynaProperty</code>'s
151     * that support this feature.
152     *
153     * <p>There are issues with serializing primitive class types on certain JVM versions
154     * (including java 1.3).
155     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
156     *
157     * @return the Class for the content type if this is an indexed <code>DynaProperty</code> 
158     * and this feature is supported. Otherwise null.
159     */
160    public Class getContentType() {
161        return contentType;
162    }
163    
164    // --------------------------------------------------------- Public Methods
165
166
167    /**
168     * Does this property represent an indexed value (ie an array or List)?
169     *
170     * @return <code>true</code> if the property is indexed (i.e. is a List or
171     * array), otherwise <code>false</code>
172     */
173    public boolean isIndexed() {
174
175        if (type == null) {
176            return (false);
177        } else if (type.isArray()) {
178            return (true);
179        } else if (List.class.isAssignableFrom(type)) {
180            return (true);
181        } else {
182            return (false);
183        }
184
185    }
186
187
188    /**
189     * Does this property represent a mapped value (ie a Map)?
190     *
191     * @return <code>true</code> if the property is a Map
192     * otherwise <code>false</code>
193     */
194    public boolean isMapped() {
195
196        if (type == null) {
197            return (false);
198        } else {
199            return (Map.class.isAssignableFrom(type));
200        }
201
202    }
203
204    /**
205     * Checks this instance against the specified Object for equality. Overrides the
206     * default refererence test for equality provided by {@link java.lang.Object#equals(Object)}  
207     * @param obj The object to compare to
208     * @return <code>true</code> if object is a dyna property with the same name
209     * type and content type, otherwise <code>false</code>
210     * @since 1.8.0
211     */
212    public boolean equals(final Object obj) {
213
214        boolean result = false;
215
216        result = (obj == this);
217
218        if ((!result) && obj instanceof DynaProperty) {
219            final DynaProperty that = (DynaProperty) obj;
220            result = 
221               ((this.name == null) ? (that.name == null) : (this.name.equals(that.name))) &&
222               ((this.type == null) ? (that.type == null) : (this.type.equals(that.type))) &&
223               ((this.contentType == null) ? (that.contentType == null) : (this.contentType.equals(that.contentType)));
224        }
225
226        return result;
227    }
228
229    /**
230     * @return the hashcode for this dyna property
231     * @see java.lang.Object#hashCode
232     * @since 1.8.0
233     */
234    public int hashCode() {
235
236       int result = 1;
237       
238       result = result * 31 + ((name == null) ? 0 : name.hashCode());
239       result = result * 31 + ((type == null) ? 0 : type.hashCode());
240       result = result * 31 + ((contentType == null) ? 0 : contentType.hashCode());
241
242       return result;
243    }
244
245    /**
246     * Return a String representation of this Object.
247     * @return a String representation of the dyna property
248     */
249    public String toString() {
250
251        StringBuffer sb = new StringBuffer("DynaProperty[name=");
252        sb.append(this.name);
253        sb.append(",type=");
254        sb.append(this.type);
255        if (isMapped() || isIndexed()) {
256            sb.append(" <").append(this.contentType).append(">");
257        }
258        sb.append("]");
259        return (sb.toString());
260
261    }
262
263    // --------------------------------------------------------- Serialization helper methods
264    
265    /**
266     * Writes this object safely.
267     * There are issues with serializing primitive class types on certain JVM versions
268     * (including java 1.3).
269     * This method provides a workaround.
270     */
271    private void writeObject(ObjectOutputStream out) throws IOException {
272        
273        writeAnyClass(this.type,out);
274        
275        if (isMapped() || isIndexed()) {
276            writeAnyClass(this.contentType,out);
277        }
278        
279        // write out other values
280        out.defaultWriteObject();
281    }
282
283    /**
284     * Write a class using safe encoding to workaround java 1.3 serialization bug.
285     */
286    private void writeAnyClass(Class clazz, ObjectOutputStream out) throws IOException {
287        // safely write out any class
288        int primitiveType = 0;
289        if (Boolean.TYPE.equals(clazz)) {
290            primitiveType = BOOLEAN_TYPE;
291        } else if (Byte.TYPE.equals(clazz)) {
292            primitiveType = BYTE_TYPE;
293        } else if (Character.TYPE.equals(clazz)) {
294            primitiveType = CHAR_TYPE;
295        } else if (Double.TYPE.equals(clazz)) {
296            primitiveType = DOUBLE_TYPE;
297        } else if (Float.TYPE.equals(clazz)) {
298            primitiveType = FLOAT_TYPE;
299        } else if (Integer.TYPE.equals(clazz)) {
300            primitiveType = INT_TYPE;
301        } else if (Long.TYPE.equals(clazz)) {
302            primitiveType = LONG_TYPE;
303        } else if (Short.TYPE.equals(clazz)) {
304            primitiveType = SHORT_TYPE;
305        }
306        
307        if (primitiveType == 0) {
308            // then it's not a primitive type
309            out.writeBoolean(false);
310            out.writeObject(clazz);
311        } else {
312            // we'll write out a constant instead
313            out.writeBoolean(true);
314            out.writeInt(primitiveType);
315        }
316    }
317    
318    /**
319     * Reads field values for this object safely.
320     * There are issues with serializing primitive class types on certain JVM versions
321     * (including java 1.3).
322     * This method provides a workaround.
323     *
324     * @throws StreamCorruptedException when the stream data values are outside expected range 
325     */
326    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
327        
328        this.type = readAnyClass(in);
329        
330        if (isMapped() || isIndexed()) {
331            this.contentType = readAnyClass(in);
332        }
333        
334        // read other values
335        in.defaultReadObject();
336    }
337    
338
339    /**
340     * Reads a class using safe encoding to workaround java 1.3 serialization bug.
341     */
342    private Class readAnyClass(ObjectInputStream in) throws IOException, ClassNotFoundException {
343        // read back type class safely 
344        if (in.readBoolean()) {
345            // it's a type constant
346            switch (in.readInt()) {
347            
348                case BOOLEAN_TYPE: return   Boolean.TYPE;
349                case BYTE_TYPE:    return      Byte.TYPE;
350                case CHAR_TYPE:    return Character.TYPE;
351                case DOUBLE_TYPE:  return    Double.TYPE;
352                case FLOAT_TYPE:   return     Float.TYPE;
353                case INT_TYPE:     return   Integer.TYPE;
354                case LONG_TYPE:    return      Long.TYPE;
355                case SHORT_TYPE:   return     Short.TYPE;
356                default:
357                    // something's gone wrong
358                    throw new StreamCorruptedException(
359                        "Invalid primitive type. "
360                        + "Check version of beanutils used to serialize is compatible.");
361
362            }
363              
364        } else {
365            // it's another class
366            return ((Class) in.readObject());
367        }
368    }
369}