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        private static final long serialVersionUID = -3084907613499830175L;
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(final 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(final String name, final 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(final String name, final Class<?> type, final 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    @Override
213    public boolean equals(final Object obj) {
214
215        boolean result = false;
216
217        result = (obj == this);
218
219        if ((!result) && obj instanceof DynaProperty) {
220            final DynaProperty that = (DynaProperty) obj;
221            result =
222               ((this.name == null) ? (that.name == null) : (this.name.equals(that.name))) &&
223               ((this.type == null) ? (that.type == null) : (this.type.equals(that.type))) &&
224               ((this.contentType == null) ? (that.contentType == null) : (this.contentType.equals(that.contentType)));
225        }
226
227        return result;
228    }
229
230    /**
231     * @return the hashcode for this dyna property
232     * @see java.lang.Object#hashCode
233     * @since 1.8.0
234     */
235    @Override
236    public int hashCode() {
237
238       int result = 1;
239
240       result = result * 31 + ((name == null) ? 0 : name.hashCode());
241       result = result * 31 + ((type == null) ? 0 : type.hashCode());
242       result = result * 31 + ((contentType == null) ? 0 : contentType.hashCode());
243
244       return result;
245    }
246
247    /**
248     * Return a String representation of this Object.
249     * @return a String representation of the dyna property
250     */
251    @Override
252    public String toString() {
253
254        final StringBuilder sb = new StringBuilder("DynaProperty[name=");
255        sb.append(this.name);
256        sb.append(",type=");
257        sb.append(this.type);
258        if (isMapped() || isIndexed()) {
259            sb.append(" <").append(this.contentType).append(">");
260        }
261        sb.append("]");
262        return (sb.toString());
263
264    }
265
266    // --------------------------------------------------------- Serialization helper methods
267
268    /**
269     * Writes this object safely.
270     * There are issues with serializing primitive class types on certain JVM versions
271     * (including java 1.3).
272     * This method provides a workaround.
273     * 
274     * @param out {@link ObjectOutputStream} to write object to
275     * @throws IOException if the object can't be written
276     */
277    private void writeObject(final ObjectOutputStream out) throws IOException {
278
279        writeAnyClass(this.type,out);
280
281        if (isMapped() || isIndexed()) {
282            writeAnyClass(this.contentType,out);
283        }
284
285        // write out other values
286        out.defaultWriteObject();
287    }
288
289    /**
290     * Write a class using safe encoding to workaround java 1.3 serialization bug.
291     */
292    private void writeAnyClass(final Class<?> clazz, final ObjectOutputStream out) throws IOException {
293        // safely write out any class
294        int primitiveType = 0;
295        if (Boolean.TYPE.equals(clazz)) {
296            primitiveType = BOOLEAN_TYPE;
297        } else if (Byte.TYPE.equals(clazz)) {
298            primitiveType = BYTE_TYPE;
299        } else if (Character.TYPE.equals(clazz)) {
300            primitiveType = CHAR_TYPE;
301        } else if (Double.TYPE.equals(clazz)) {
302            primitiveType = DOUBLE_TYPE;
303        } else if (Float.TYPE.equals(clazz)) {
304            primitiveType = FLOAT_TYPE;
305        } else if (Integer.TYPE.equals(clazz)) {
306            primitiveType = INT_TYPE;
307        } else if (Long.TYPE.equals(clazz)) {
308            primitiveType = LONG_TYPE;
309        } else if (Short.TYPE.equals(clazz)) {
310            primitiveType = SHORT_TYPE;
311        }
312
313        if (primitiveType == 0) {
314            // then it's not a primitive type
315            out.writeBoolean(false);
316            out.writeObject(clazz);
317        } else {
318            // we'll write out a constant instead
319            out.writeBoolean(true);
320            out.writeInt(primitiveType);
321        }
322    }
323
324    /**
325     * Reads field values for this object safely.
326     * There are issues with serializing primitive class types on certain JVM versions
327     * (including java 1.3).
328     * This method provides a workaround.
329     * 
330     * @param in {@link ObjectInputStream} to read object from
331     * @throws StreamCorruptedException when the stream data values are outside expected range
332     * @throws IOException if the input stream can't be read
333     * @throws ClassNotFoundException When trying to read an object of class that is not on the classpath
334     */
335    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
336
337        this.type = readAnyClass(in);
338
339        if (isMapped() || isIndexed()) {
340            this.contentType = readAnyClass(in);
341        }
342
343        // read other values
344        in.defaultReadObject();
345    }
346
347
348    /**
349     * Reads a class using safe encoding to workaround java 1.3 serialization bug.
350     */
351    private Class<?> readAnyClass(final ObjectInputStream in) throws IOException, ClassNotFoundException {
352        // read back type class safely
353        if (in.readBoolean()) {
354            // it's a type constant
355            switch (in.readInt()) {
356
357                case BOOLEAN_TYPE: return   Boolean.TYPE;
358                case BYTE_TYPE:    return      Byte.TYPE;
359                case CHAR_TYPE:    return Character.TYPE;
360                case DOUBLE_TYPE:  return    Double.TYPE;
361                case FLOAT_TYPE:   return     Float.TYPE;
362                case INT_TYPE:     return   Integer.TYPE;
363                case LONG_TYPE:    return      Long.TYPE;
364                case SHORT_TYPE:   return     Short.TYPE;
365                default:
366                    // something's gone wrong
367                    throw new StreamCorruptedException(
368                        "Invalid primitive type. "
369                        + "Check version of beanutils used to serialize is compatible.");
370
371            }
372
373        } else {
374            // it's another class
375            return ((Class<?>) in.readObject());
376        }
377    }
378}