libjava/java/beans/IndexedPropertyDescriptor.java

   1 /* java.beans.IndexedPropertyDescriptor
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.beans;
  40
  41 import java.util.*;
  42 import java.lang.reflect.*;
  43
  44 /**
  45  ** IndexedPropertyDescriptor describes information about a JavaBean
  46  ** indexed property, by which we mean an array-like property that
  47  ** has been exposed via a pair of get and set methods and another
  48  ** pair that allows you to get to the property by an index.<P>
  49  **
  50  ** An example property would have four methods like this:<P>
  51  ** <CODE>FooBar[] getFoo()</CODE><BR>
  52  ** <CODE>void setFoo(FooBar[])</CODE><BR>
  53  ** <CODE>FooBar getFoo(int)</CODE><BR>
  54  ** <CODE>void setFoo(int,FooBar)</CODE><P>
  55  **
  56  ** The constraints put on get and set methods are:<P>
  57  ** <OL>
  58  ** <LI>There must be at least a get(int) or a set(int,...) method.
  59  ** Nothing else is required.  <B>Spec note:</B>One nice restriction
  60  ** would be that if there is a get() there must be a get(int), same
  61  ** with set, but that is not in the spec and is fairly harmless.)</LI>
  62  ** <LI>A get array method must have signature
  63  **     <CODE>&lt;propertyType&gt;[] &lt;getMethodName&gt;()</CODE></LI>
  64  ** <LI>A set array method must have signature
  65  **     <CODE>void &lt;setMethodName&gt;(&lt;propertyType&gt;[])</CODE></LI>
  66  ** <LI>A get index method must have signature
  67  **     <CODE>&lt;propertyType&gt; &lt;getMethodName&gt;(int)</CODE></LI>
  68  ** <LI>A set index method must have signature
  69  **     <CODE>void &lt;setMethodName&gt;(int,&lt;propertyType&gt;)</CODE></LI>
  70  ** <LI>All these methods may throw any exception.</LI>
  71  ** <LI>All these methods must be public.</LI>
  72  ** </OL>
  73  **
  74  ** @author John Keiser
  75  ** @since JDK1.1
  76  ** @version 1.1.0, 26 Jul 1998
  77  **/
  78
  79 public class IndexedPropertyDescriptor extends PropertyDescriptor {
  80         private Class indexedPropertyType;
  81         private Method setIndex;
  82         private Method getIndex;
  83
  84         /** Create a new IndexedPropertyDescriptor by introspection.
  85          ** This form of constructor creates the PropertyDescriptor by
  86          ** looking for getter methods named <CODE>get&lt;name&gt;()</CODE>
  87          ** and setter methods named
  88          ** <CODE>set&lt;name&gt;()</CODE> in class
  89          ** <CODE>&lt;beanClass&gt;</CODE>, where &lt;name&gt; has its
  90          ** first letter capitalized by the constructor.<P>
  91          **
  92          ** <B>Implementation note:</B> If there is a get(int) method,
  93          ** then the return type of that method is used to find the
  94          ** remaining methods.  If there is no get method, then the
  95          ** set(int) method is searched for exhaustively and that type
  96          ** is used to find the others.<P>
  97          **
  98          ** <B>Spec note:</B>
  99          ** If there is no get(int) method and multiple set(int) methods with
 100          ** the same name and the correct parameters (different type of course),
 101          ** then an IntrospectionException is thrown.  While Sun's spec
 102          ** does not state this, it can make Bean behavior different on
 103          ** different systems (since method order is not guaranteed) and as
 104          ** such, can be treated as a bug in the spec.  I am not aware of
 105          ** whether Sun's implementation catches this.
 106          **
 107          ** @param name the programmatic name of the property, usually
 108          **             starting with a lowercase letter (e.g. fooManChu
 109          **             instead of FooManChu).
 110          ** @param beanClass the class the get and set methods live in.
 111          ** @exception IntrospectionException if the methods are not found or invalid.
 112          **/
 113         public IndexedPropertyDescriptor(String name, Class beanClass) throws IntrospectionException {
 114                 super(name);
 115                 String capitalized;
 116                 try {
 117                         capitalized = Character.toUpperCase(name.charAt(0)) + name.substring(1);
 118                 } catch(StringIndexOutOfBoundsException e) {
 119                         capitalized = "";
 120                 }
 121                 findMethods(beanClass, "get" + capitalized, "set" + capitalized, "get" + capitalized, "set" + capitalized);
 122         }
 123
 124         /** Create a new IndexedPropertyDescriptor by introspection.
 125          ** This form of constructor allows you to specify the
 126          ** names of the get and set methods to search for.<P>
 127          **
 128          ** <B>Implementation note:</B> If there is a get(int) method,
 129          ** then the return type of that method is used to find the
 130          ** remaining methods.  If there is no get method, then the
 131          ** set(int) method is searched for exhaustively and that type
 132          ** is used to find the others.<P>
 133          **
 134          ** <B>Spec note:</B>
 135          ** If there is no get(int) method and multiple set(int) methods with
 136          ** the same name and the correct parameters (different type of course),
 137          ** then an IntrospectionException is thrown.  While Sun's spec
 138          ** does not state this, it can make Bean behavior different on
 139          ** different systems (since method order is not guaranteed) and as
 140          ** such, can be treated as a bug in the spec.  I am not aware of
 141          ** whether Sun's implementation catches this.
 142          **
 143          ** @param name the programmatic name of the property, usually
 144          **             starting with a lowercase letter (e.g. fooManChu
 145          **             instead of FooManChu).
 146          ** @param beanClass the class the get and set methods live in.
 147          ** @param getMethodName the name of the get array method.
 148          ** @param setMethodName the name of the set array method.
 149          ** @param getIndexName the name of the get index method.
 150          ** @param setIndexName the name of the set index method.
 151          ** @exception IntrospectionException if the methods are not found or invalid.
 152          **/
 153         public IndexedPropertyDescriptor(String name, Class beanClass, String getMethodName, String setMethodName, String getIndexName, String setIndexName) throws IntrospectionException {
 154                 super(name);
 155                 findMethods(beanClass, getMethodName, setMethodName, getIndexName, setIndexName);
 156         }
 157
 158         /** Create a new PropertyDescriptor using explicit Methods.
 159          ** Note that the methods will be checked for conformance to standard
 160          ** Property method rules, as described above at the top of this class.
 161          **
 162          ** @param name the programmatic name of the property, usually
 163          **             starting with a lowercase letter (e.g. fooManChu
 164          **             instead of FooManChu).
 165          ** @param getMethod the get array method.
 166          ** @param setMethod the set array method.
 167          ** @param getIndex the get index method.
 168          ** @param setIndex the set index method.
 169          ** @exception IntrospectionException if the methods are not found or invalid.
 170          **/
 171         public IndexedPropertyDescriptor(String name, Method getMethod, Method setMethod, Method getIndex, Method setIndex) throws IntrospectionException {
 172                 super(name);
 173                 if(getMethod != null && getMethod.getParameterTypes().length > 0) {
 174                         throw new IntrospectionException("get method has parameters");
 175                 }
 176                 if(getMethod != null && setMethod.getParameterTypes().length != 1) {
 177                         throw new IntrospectionException("set method does not have exactly one parameter");
 178                 }
 179                 if(getMethod != null && setMethod != null) {
 180                         if(!getMethod.getReturnType().equals(setMethod.getParameterTypes()[0])) {
 181                                 throw new IntrospectionException("set and get methods do not share the same type");
 182                         }
 183                         if(!getMethod.getDeclaringClass().isAssignableFrom(setMethod.getDeclaringClass())
 184                            && !setMethod.getDeclaringClass().isAssignableFrom(getMethod.getDeclaringClass())) {
 185                                 throw new IntrospectionException("set and get methods are not in the same class.");
 186                         }
 187                 }
 188
 189                 if(getIndex != null && (getIndex.getParameterTypes().length != 1
 190                    || !(getIndex.getParameterTypes()[0]).equals(java.lang.Integer.TYPE))) {
 191                         throw new IntrospectionException("get index method has wrong parameters");
 192                 }
 193                 if(setIndex != null && (setIndex.getParameterTypes().length != 2
 194                    || !(setIndex.getParameterTypes()[0]).equals(java.lang.Integer.TYPE))) {
 195                         throw new IntrospectionException("set index method has wrong parameters");
 196                 }
 197                 if(getIndex != null && setIndex != null) {
 198                         if(!getIndex.getReturnType().equals(setIndex.getParameterTypes()[1])) {
 199                                 throw new IntrospectionException("set index methods do not share the same type");
 200                         }
 201                         if(!getIndex.getDeclaringClass().isAssignableFrom(setIndex.getDeclaringClass())
 202                            && !setIndex.getDeclaringClass().isAssignableFrom(getIndex.getDeclaringClass())) {
 203                                 throw new IntrospectionException("get and set index methods are not in the same class.");
 204                         }
 205                 }
 206
 207                 if(getIndex != null && getMethod != null && !getIndex.getDeclaringClass().isAssignableFrom(getMethod.getDeclaringClass())
 208                    && !getMethod.getDeclaringClass().isAssignableFrom(getIndex.getDeclaringClass())) {
 209                         throw new IntrospectionException("methods are not in the same class.");
 210                 }
 211
 212                 if(getIndex != null && getMethod != null && !Array.newInstance(getIndex.getReturnType(),0).getClass().equals(getMethod.getReturnType())) {
 213                         throw new IntrospectionException("array methods do not match index methods.");
 214                 }
 215
 216                 this.getMethod = getMethod;
 217                 this.setMethod = setMethod;
 218                 this.getIndex = getIndex;
 219                 this.setIndex = getIndex;
 220                 this.indexedPropertyType = getIndex != null ? getIndex.getReturnType() : setIndex.getParameterTypes()[1];
 221                 this.propertyType = getMethod != null ? getMethod.getReturnType() : (setMethod != null ? setMethod.getParameterTypes()[0] : Array.newInstance(this.indexedPropertyType,0).getClass());
 222         }
 223
 224         public Class getIndexedPropertyType() {
 225                 return indexedPropertyType;
 226         }
 227
 228         public Method getIndexedReadMethod() {
 229                 return getIndex;
 230         }
 231
 232         public Method getIndexedWriteMethod() {
 233                 return setIndex;
 234         }
 235
 236         private void findMethods(Class beanClass, String getMethodName, String setMethodName, String getIndexName, String setIndexName) throws IntrospectionException {
 237                 try {
 238                         if(getIndexName != null) {
 239                                 try {
 240                                         Class[] getArgs = new Class[1];
 241                                         getArgs[0] = java.lang.Integer.TYPE;
 242                                         getIndex = beanClass.getMethod(getIndexName,getArgs);
 243                                         indexedPropertyType = getIndex.getReturnType();
 244                                 } catch(NoSuchMethodException E) {
 245                                 }
 246                         }
 247                         if(getIndex != null) {
 248                                 if(setIndexName != null) {
 249                                         try {
 250                                                 Class[] setArgs = new Class[2];
 251                                                 setArgs[0] = java.lang.Integer.TYPE;
 252                                                 setArgs[1] = indexedPropertyType;
 253                                                 setIndex = beanClass.getMethod(setIndexName,setArgs);
 254                                                 if(!setIndex.getReturnType().equals(java.lang.Void.TYPE)) {
 255                                                         throw new IntrospectionException(setIndexName + " has non-void return type");
 256                                                 }
 257                                         } catch(NoSuchMethodException E) {
 258                                         }
 259                                 }
 260                         } else if(setIndexName != null) {
 261                                 Method[] m = beanClass.getMethods();
 262                                 for(int i=0;i<m.length;i++) {
 263                                         Method current = m[i];
 264                                         if(current.getName().equals(setIndexName)
 265                                            && current.getParameterTypes().length == 2
 266                                            && (current.getParameterTypes()[0]).equals(java.lang.Integer.TYPE)
 267                                            && current.getReturnType().equals(java.lang.Void.TYPE)) {
 268                                                 if(setIndex != null) {
 269                                                         throw new IntrospectionException("Multiple, different set methods found that fit the bill!");
 270                                                 } else {
 271                                                         setIndex = current;
 272                                                         indexedPropertyType = current.getParameterTypes()[1];
 273                                                 }
 274                                         }
 275                                 }
 276                                 if(setIndex == null) {
 277                                         throw new IntrospectionException("Cannot find get or set methods.");
 278                                 }
 279                         } else {
 280                                 throw new IntrospectionException("Cannot find get or set methods.");
 281                         }
 282
 283                         Class arrayType = Array.newInstance(indexedPropertyType,0).getClass();
 284
 285                         Class[] setArgs = new Class[1];
 286                         setArgs[0] = arrayType;
 287                         try {
 288                                 setMethod = beanClass.getMethod(setMethodName,setArgs);
 289                                 if(!setMethod.getReturnType().equals(java.lang.Void.TYPE)) {
 290                                         setMethod = null;
 291                                 }
 292                         } catch(NoSuchMethodException E) {
 293                         }
 294
 295                         Class[] getArgs = new Class[0];
 296                         try {
 297                                 getMethod = beanClass.getMethod(getMethodName,getArgs);
 298                                 if(!getMethod.getReturnType().equals(arrayType)) {
 299                                         getMethod = null;
 300                                 }
 301                         } catch(NoSuchMethodException E) {
 302                         }
 303                 } catch(SecurityException E) {
 304                         throw new IntrospectionException("SecurityException while trying to find methods.");
 305                 }
 306         }
 307 }