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: package org.apache.commons.beanutils;
019:
020: import java.io.IOException;
021: import java.io.Serializable;
022: import java.io.ObjectOutputStream;
023: import java.io.ObjectInputStream;
024: import java.io.StreamCorruptedException;
025: import java.util.List;
026: import java.util.Map;
027:
028: /**
029: * <p>The metadata describing an individual property of a DynaBean.</p>
030: *
031: * <p>The meta contains an <em>optional</em> content type property ({@link #getContentType})
032: * for use by mapped and iterated properties.
033: * A mapped or iterated property may choose to indicate the type it expects.
034: * The DynaBean implementation may choose to enforce this type on its entries.
035: * Alternatively, an implementatin may choose to ignore this property.
036: * All keys for maps must be of type String so no meta data is needed for map keys.</p>
037: *
038: * @author Craig R. McClanahan
039: * @version $Revision: 555824 $ $Date: 2007-07-13 01:27:15 +0100 (Fri, 13 Jul 2007) $
040: */
041:
042: public class DynaProperty implements Serializable {
043:
044: // ----------------------------------------------------------- Constants
045:
046: /*
047: * There are issues with serializing primitive class types on certain JVM versions
048: * (including java 1.3).
049: * This class uses a custom serialization implementation that writes an integer
050: * for these primitive class.
051: * This list of constants are the ones used in serialization.
052: * If these values are changed, then older versions will no longer be read correctly
053: */
054: private static final int BOOLEAN_TYPE = 1;
055: private static final int BYTE_TYPE = 2;
056: private static final int CHAR_TYPE = 3;
057: private static final int DOUBLE_TYPE = 4;
058: private static final int FLOAT_TYPE = 5;
059: private static final int INT_TYPE = 6;
060: private static final int LONG_TYPE = 7;
061: private static final int SHORT_TYPE = 8;
062:
063: // ----------------------------------------------------------- Constructors
064:
065: /**
066: * Construct a property that accepts any data type.
067: *
068: * @param name Name of the property being described
069: */
070: public DynaProperty(String name) {
071:
072: this (name, Object.class);
073:
074: }
075:
076: /**
077: * Construct a property of the specified data type.
078: *
079: * @param name Name of the property being described
080: * @param type Java class representing the property data type
081: */
082: public DynaProperty(String name, Class type) {
083:
084: super ();
085: this .name = name;
086: this .type = type;
087: if (type != null && type.isArray()) {
088: this .contentType = type.getComponentType();
089: }
090:
091: }
092:
093: /**
094: * Construct an indexed or mapped <code>DynaProperty</code> that supports (pseudo)-introspection
095: * of the content type.
096: *
097: * @param name Name of the property being described
098: * @param type Java class representing the property data type
099: * @param contentType Class that all indexed or mapped elements are instances of
100: */
101: public DynaProperty(String name, Class type, Class contentType) {
102:
103: super ();
104: this .name = name;
105: this .type = type;
106: this .contentType = contentType;
107:
108: }
109:
110: // ------------------------------------------------------------- Properties
111:
112: /** Property name */
113: protected String name = null;
114:
115: /**
116: * Get the name of this property.
117: * @return the name of the property
118: */
119: public String getName() {
120: return (this .name);
121: }
122:
123: /** Property type */
124: protected transient Class type = null;
125:
126: /**
127: * <p>Gets the Java class representing the data type of the underlying property
128: * values.</p>
129: *
130: * <p>There are issues with serializing primitive class types on certain JVM versions
131: * (including java 1.3).
132: * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
133: *
134: * <p><strong>Please leave this field as <code>transient</code></strong></p>
135: *
136: * @return the property type
137: */
138: public Class getType() {
139: return (this .type);
140: }
141:
142: /** The <em>(optional)</em> type of content elements for indexed <code>DynaProperty</code> */
143: protected transient Class contentType;
144:
145: /**
146: * Gets the <em>(optional)</em> type of the indexed content for <code>DynaProperty</code>'s
147: * that support this feature.
148: *
149: * <p>There are issues with serializing primitive class types on certain JVM versions
150: * (including java 1.3).
151: * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
152: *
153: * @return the Class for the content type if this is an indexed <code>DynaProperty</code>
154: * and this feature is supported. Otherwise null.
155: */
156: public Class getContentType() {
157: return contentType;
158: }
159:
160: // --------------------------------------------------------- Public Methods
161:
162: /**
163: * Does this property represent an indexed value (ie an array or List)?
164: *
165: * @return <code>true</code> if the property is indexed (i.e. is a List or
166: * array), otherwise <code>false</code>
167: */
168: public boolean isIndexed() {
169:
170: if (type == null) {
171: return (false);
172: } else if (type.isArray()) {
173: return (true);
174: } else if (List.class.isAssignableFrom(type)) {
175: return (true);
176: } else {
177: return (false);
178: }
179:
180: }
181:
182: /**
183: * Does this property represent a mapped value (ie a Map)?
184: *
185: * @return <code>true</code> if the property is a Map
186: * otherwise <code>false</code>
187: */
188: public boolean isMapped() {
189:
190: if (type == null) {
191: return (false);
192: } else {
193: return (Map.class.isAssignableFrom(type));
194: }
195:
196: }
197:
198: /**
199: * Checks this instance against the specified Object for equality. Overrides the
200: * default refererence test for equality provided by {@link java.lang.Object#equals(Object)}
201: * @param obj The object to compare to
202: * @return <code>true</code> if object is a dyna property with the same name
203: * type and content type, otherwise <code>false</code>
204: */
205: public boolean equals(final Object obj) {
206:
207: boolean result = false;
208:
209: result = (obj == this );
210:
211: if ((!result) && obj instanceof DynaProperty) {
212: final DynaProperty that = (DynaProperty) obj;
213: result = ((this .name == null) ? (that.name == null)
214: : (this .name.equals(that.name)))
215: && ((this .type == null) ? (that.type == null)
216: : (this .type.equals(that.type)))
217: && ((this .contentType == null) ? (that.contentType == null)
218: : (this .contentType
219: .equals(that.contentType)));
220: }
221:
222: return result;
223: }
224:
225: /**
226: * @return the hashcode for this dyna property
227: * @see java.lang.Object#hashCode
228: */
229: public int hashCode() {
230:
231: int result = 1;
232:
233: result = result * 31 + ((name == null) ? 0 : name.hashCode());
234: result = result * 31 + ((type == null) ? 0 : type.hashCode());
235: result = result * 31
236: + ((contentType == null) ? 0 : contentType.hashCode());
237:
238: return result;
239: }
240:
241: /**
242: * Return a String representation of this Object.
243: * @return a String representation of the dyna property
244: */
245: public String toString() {
246:
247: StringBuffer sb = new StringBuffer("DynaProperty[name=");
248: sb.append(this .name);
249: sb.append(",type=");
250: sb.append(this .type);
251: if (isMapped() || isIndexed()) {
252: sb.append(" <").append(this .contentType).append(">");
253: }
254: sb.append("]");
255: return (sb.toString());
256:
257: }
258:
259: // --------------------------------------------------------- Serialization helper methods
260:
261: /**
262: * Writes this object safely.
263: * There are issues with serializing primitive class types on certain JVM versions
264: * (including java 1.3).
265: * This method provides a workaround.
266: */
267: private void writeObject(ObjectOutputStream out) throws IOException {
268:
269: writeAnyClass(this .type, out);
270:
271: if (isMapped() || isIndexed()) {
272: writeAnyClass(this .contentType, out);
273: }
274:
275: // write out other values
276: out.defaultWriteObject();
277: }
278:
279: /**
280: * Write a class using safe encoding to workaround java 1.3 serialization bug.
281: */
282: private void writeAnyClass(Class clazz, ObjectOutputStream out)
283: throws IOException {
284: // safely write out any class
285: int primitiveType = 0;
286: if (Boolean.TYPE.equals(clazz)) {
287: primitiveType = BOOLEAN_TYPE;
288: } else if (Byte.TYPE.equals(clazz)) {
289: primitiveType = BYTE_TYPE;
290: } else if (Character.TYPE.equals(clazz)) {
291: primitiveType = CHAR_TYPE;
292: } else if (Double.TYPE.equals(clazz)) {
293: primitiveType = DOUBLE_TYPE;
294: } else if (Float.TYPE.equals(clazz)) {
295: primitiveType = FLOAT_TYPE;
296: } else if (Integer.TYPE.equals(clazz)) {
297: primitiveType = INT_TYPE;
298: } else if (Long.TYPE.equals(clazz)) {
299: primitiveType = LONG_TYPE;
300: } else if (Short.TYPE.equals(clazz)) {
301: primitiveType = SHORT_TYPE;
302: }
303:
304: if (primitiveType == 0) {
305: // then it's not a primitive type
306: out.writeBoolean(false);
307: out.writeObject(clazz);
308: } else {
309: // we'll write out a constant instead
310: out.writeBoolean(true);
311: out.writeInt(primitiveType);
312: }
313: }
314:
315: /**
316: * Reads field values for this object safely.
317: * There are issues with serializing primitive class types on certain JVM versions
318: * (including java 1.3).
319: * This method provides a workaround.
320: *
321: * @throws StreamCorruptedException when the stream data values are outside expected range
322: */
323: private void readObject(ObjectInputStream in) throws IOException,
324: ClassNotFoundException {
325:
326: this .type = readAnyClass(in);
327:
328: if (isMapped() || isIndexed()) {
329: this .contentType = readAnyClass(in);
330: }
331:
332: // read other values
333: in.defaultReadObject();
334: }
335:
336: /**
337: * Reads a class using safe encoding to workaround java 1.3 serialization bug.
338: */
339: private Class readAnyClass(ObjectInputStream in)
340: throws IOException, ClassNotFoundException {
341: // read back type class safely
342: if (in.readBoolean()) {
343: // it's a type constant
344: switch (in.readInt()) {
345:
346: case BOOLEAN_TYPE:
347: return Boolean.TYPE;
348: case BYTE_TYPE:
349: return Byte.TYPE;
350: case CHAR_TYPE:
351: return Character.TYPE;
352: case DOUBLE_TYPE:
353: return Double.TYPE;
354: case FLOAT_TYPE:
355: return Float.TYPE;
356: case INT_TYPE:
357: return Integer.TYPE;
358: case LONG_TYPE:
359: return Long.TYPE;
360: case SHORT_TYPE:
361: return Short.TYPE;
362: default:
363: // something's gone wrong
364: throw new StreamCorruptedException(
365: "Invalid primitive type. "
366: + "Check version of beanutils used to serialize is compatible.");
367:
368: }
369:
370: } else {
371: // it's another class
372: return ((Class) in.readObject());
373: }
374: }
375: }
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