Source for java.beans.IndexedPropertyDescriptor

   1: /* java.beans.IndexedPropertyDescriptor
   2:    Copyright (C) 1998, 2003 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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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.lang.reflect.Array;
  42: import java.lang.reflect.Method;
  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 = setIndex;
 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: }