Source code

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.ObjectInputStream;
024import java.io.ObjectOutputStream;
025import java.io.Serializable;
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 * @version $Id$
042 */
043
044public class DynaProperty implements Serializable {
045
046    // ----------------------------------------------------------- Constants
047
048    /*
049     * There are issues with serializing primitive class types on certain JVM versions
050     * (including java 1.3).
051     * This class uses a custom serialization implementation that writes an integer
052     * for these primitive class.
053     * This list of constants are the ones used in serialization.
054     * If these values are changed, then older versions will no longer be read correctly
055     */
056    private static final int BOOLEAN_TYPE = 1;
057    private static final int BYTE_TYPE = 2;
058    private static final int CHAR_TYPE = 3;
059    private static final int DOUBLE_TYPE = 4;
060    private static final int FLOAT_TYPE = 5;
061    private static final int INT_TYPE = 6;
062    private static final int LONG_TYPE = 7;
063    private static final int SHORT_TYPE = 8;
064
065
066    // ----------------------------------------------------------- Constructors
067
068
069    /**
070     * Construct a property that accepts any data type.
071     *
072     * @param name Name of the property being described
073     */
074    public DynaProperty(final String name) {
075
076        this(name, Object.class);
077
078    }
079
080
081    /**
082     * Construct a property of the specified data type.
083     *
084     * @param name Name of the property being described
085     * @param type Java class representing the property data type
086     */
087    public DynaProperty(final String name, final Class<?> type) {
088
089        super();
090        this.name = name;
091        this.type = type;
092        if (type != null && type.isArray()) {
093            this.contentType = type.getComponentType();
094        }
095
096    }
097
098    /**
099     * Construct an indexed or mapped <code>DynaProperty</code> that supports (pseudo)-introspection
100     * of the content type.
101     *
102     * @param name Name of the property being described
103     * @param type Java class representing the property data type
104     * @param contentType Class that all indexed or mapped elements are instances of
105     */
106    public DynaProperty(final String name, final Class<?> type, final Class<?> contentType) {
107
108        super();
109        this.name = name;
110        this.type = type;
111        this.contentType = contentType;
112
113    }
114
115    // ------------------------------------------------------------- Properties
116
117    /** Property name */
118    protected String name = null;
119    /**
120     * Get the name of this property.
121     * @return the name of the property
122     */
123    public String getName() {
124        return (this.name);
125    }
126
127    /** Property type */
128    protected transient Class<?> type = null;
129    /**
130     * <p>Gets the Java class representing the data type of the underlying property
131     * values.</p>
132     *
133     * <p>There are issues with serializing primitive class types on certain JVM versions
134     * (including java 1.3).
135     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
136     *
137     * <p><strong>Please leave this field as <code>transient</code></strong></p>
138     *
139     * @return the property type
140     */
141    public Class<?> getType() {
142        return (this.type);
143    }
144
145
146    /** The <em>(optional)</em> type of content elements for indexed <code>DynaProperty</code> */
147    protected transient Class<?> contentType;
148    /**
149     * Gets the <em>(optional)</em> type of the indexed content for <code>DynaProperty</code>'s
150     * that support this feature.
151     *
152     * <p>There are issues with serializing primitive class types on certain JVM versions
153     * (including java 1.3).
154     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
155     *
156     * @return the Class for the content type if this is an indexed <code>DynaProperty</code>
157     * and this feature is supported. Otherwise null.
158     */
159    public Class<?> getContentType() {
160        return contentType;
161    }
162
163    // --------------------------------------------------------- Public Methods
164
165
166    /**
167     * Does this property represent an indexed value (ie an array or List)?
168     *
169     * @return <code>true</code> if the property is indexed (i.e. is a List or
170     * array), otherwise <code>false</code>
171     */
172    public boolean isIndexed() {
173
174        if (type == null) {
175            return (false);
176        } else if (type.isArray()) {
177            return (true);
178        } else if (List.class.isAssignableFrom(type)) {
179            return (true);
180        } else {
181            return (false);
182        }
183
184    }
185
186
187    /**
188     * Does this property represent a mapped value (ie a Map)?
189     *
190     * @return <code>true</code> if the property is a Map
191     * otherwise <code>false</code>
192     */
193    public boolean isMapped() {
194
195        if (type == null) {
196            return (false);
197        } else {
198            return (Map.class.isAssignableFrom(type));
199        }
200
201    }
202
203    /**
204     * Checks this instance against the specified Object for equality. Overrides the
205     * default refererence test for equality provided by {@link java.lang.Object#equals(Object)}
206     * @param obj The object to compare to
207     * @return <code>true</code> if object is a dyna property with the same name
208     * type and content type, otherwise <code>false</code>
209     * @since 1.8.0
210     */
211    @Override
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    @Override
235    public int hashCode() {
236
237       int result = 1;
238
239       result = result * 31 + ((name == null) ? 0 : name.hashCode());
240       result = result * 31 + ((type == null) ? 0 : type.hashCode());
241       result = result * 31 + ((contentType == null) ? 0 : contentType.hashCode());
242
243       return result;
244    }
245
246    /**
247     * Return a String representation of this Object.
248     * @return a String representation of the dyna property
249     */
250    @Override
251    public String toString() {
252
253        final StringBuilder sb = new StringBuilder("DynaProperty[name=");
254        sb.append(this.name);
255        sb.append(",type=");
256        sb.append(this.type);
257        if (isMapped() || isIndexed()) {
258            sb.append(" <").append(this.contentType).append(">");
259        }
260        sb.append("]");
261        return (sb.toString());
262
263    }
264
265    // --------------------------------------------------------- Serialization helper methods
266
267    /**
268     * Writes this object safely.
269     * There are issues with serializing primitive class types on certain JVM versions
270     * (including java 1.3).
271     * This method provides a workaround.
272     */
273    private void writeObject(final ObjectOutputStream out) throws IOException {
274
275        writeAnyClass(this.type,out);
276
277        if (isMapped() || isIndexed()) {
278            writeAnyClass(this.contentType,out);
279        }
280
281        // write out other values
282        out.defaultWriteObject();
283    }
284
285    /**
286     * Write a class using safe encoding to workaround java 1.3 serialization bug.
287     */
288    private void writeAnyClass(final Class<?> clazz, final ObjectOutputStream out) throws IOException {
289        // safely write out any class
290        int primitiveType = 0;
291        if (Boolean.TYPE.equals(clazz)) {
292            primitiveType = BOOLEAN_TYPE;
293        } else if (Byte.TYPE.equals(clazz)) {
294            primitiveType = BYTE_TYPE;
295        } else if (Character.TYPE.equals(clazz)) {
296            primitiveType = CHAR_TYPE;
297        } else if (Double.TYPE.equals(clazz)) {
298            primitiveType = DOUBLE_TYPE;
299        } else if (Float.TYPE.equals(clazz)) {
300            primitiveType = FLOAT_TYPE;
301        } else if (Integer.TYPE.equals(clazz)) {
302            primitiveType = INT_TYPE;
303        } else if (Long.TYPE.equals(clazz)) {
304            primitiveType = LONG_TYPE;
305        } else if (Short.TYPE.equals(clazz)) {
306            primitiveType = SHORT_TYPE;
307        }
308
309        if (primitiveType == 0) {
310            // then it's not a primitive type
311            out.writeBoolean(false);
312            out.writeObject(clazz);
313        } else {
314            // we'll write out a constant instead
315            out.writeBoolean(true);
316            out.writeInt(primitiveType);
317        }
318    }
319
320    /**
321     * Reads field values for this object safely.
322     * There are issues with serializing primitive class types on certain JVM versions
323     * (including java 1.3).
324     * This method provides a workaround.
325     *
326     * @throws StreamCorruptedException when the stream data values are outside expected range
327     */
328    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
329
330        this.type = readAnyClass(in);
331
332        if (isMapped() || isIndexed()) {
333            this.contentType = readAnyClass(in);
334        }
335
336        // read other values
337        in.defaultReadObject();
338    }
339
340
341    /**
342     * Reads a class using safe encoding to workaround java 1.3 serialization bug.
343     */
344    private Class<?> readAnyClass(final ObjectInputStream in) throws IOException, ClassNotFoundException {
345        // read back type class safely
346        if (in.readBoolean()) {
347            // it's a type constant
348            switch (in.readInt()) {
349
350                case BOOLEAN_TYPE: return   Boolean.TYPE;
351                case BYTE_TYPE:    return      Byte.TYPE;
352                case CHAR_TYPE:    return Character.TYPE;
353                case DOUBLE_TYPE:  return    Double.TYPE;
354                case FLOAT_TYPE:   return     Float.TYPE;
355                case INT_TYPE:     return   Integer.TYPE;
356                case LONG_TYPE:    return      Long.TYPE;
357                case SHORT_TYPE:   return     Short.TYPE;
358                default:
359                    // something's gone wrong
360                    throw new StreamCorruptedException(
361                        "Invalid primitive type. "
362                        + "Check version of beanutils used to serialize is compatible.");
363
364            }
365
366        } else {
367            // it's another class
368            return ((Class<?>) in.readObject());
369        }
370    }
371}