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authorTom Tromey <tromey@gcc.gnu.org>2000-05-19 17:55:34 +0000
committerTom Tromey <tromey@gcc.gnu.org>2000-05-19 17:55:34 +0000
commit6c80c45e3010bfe992b41dd8800d2c4b65e0d5ef (patch)
tree88cf0d32aea197ea8e8198e1206b04c820308615 /libjava/java/beans/Introspector.java
parent021c89ed68c151c45021fccf1bb5338ee817314c (diff)
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Jumbo patch:
* Imported beans and serialization * Updated IA-64 port * Miscellaneous bug fixes From-SVN: r34028
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+/* java.beans.Introspector
+ Copyright (C) 1998 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+As a special exception, if you link this library with other files to
+produce an executable, this library does not by itself cause the
+resulting executable to be covered by the GNU General Public License.
+This exception does not however invalidate any other reasons why the
+executable file might be covered by the GNU General Public License. */
+
+
+package java.beans;
+
+import gnu.java.beans.*;
+import java.util.*;
+import java.lang.reflect.*;
+import gnu.java.lang.*;
+
+/**
+ ** Introspector is the class that does the bulk of the
+ ** design-time work in Java Beans. Every class must have
+ ** a BeanInfo in order for an RAD tool to use it; but, as
+ ** promised, you don't have to write the BeanInfo class
+ ** yourself if you don't want to. All you have to do is
+ ** call getBeanInfo() in the Introspector and it will use
+ ** standard JavaBeans-defined method signatures to
+ ** determine the information about your class.<P>
+ **
+ ** Don't worry about it too much, though: you can provide
+ ** JavaBeans with as much customized information as you
+ ** want, or as little as you want, using the BeanInfo
+ ** interface (see BeanInfo for details).<P>
+ **
+ ** <STRONG>Order of Operations</STRONG><P>
+ **
+ ** When you call getBeanInfo(class c), the Introspector
+ ** first searches for BeanInfo class to see if you
+ ** provided any explicit information. It searches for a
+ ** class named <bean class name>BeanInfo in different
+ ** packages, first searching the bean class's package
+ ** and then moving on to search the beanInfoSearchPath.<P>
+ **
+ ** If it does not find a BeanInfo class, it acts as though
+ ** it had found a BeanInfo class returning null from all
+ ** methods (meaning it should discover everything through
+ ** Introspection). If it does, then it takes the
+ ** information it finds in the BeanInfo class to be
+ ** canonical (that is, the information speaks for its
+ ** class as well as all superclasses).<P>
+ **
+ ** When it has introspected the class, calls
+ ** getBeanInfo(c.getSuperclass) and adds that information
+ ** to the information it has, not adding to any information
+ ** it already has that is canonical.<P>
+ **
+ ** <STRONG>Introspection Design Patterns</STRONG><P>
+ **
+ ** When the Introspector goes in to read the class, it
+ ** follows a well-defined order in order to not leave any
+ ** methods unaccounted for. Its job is to step over all
+ ** of the public methods in a class and determine whether
+ ** they are part of a property, an event, or a method (in
+ ** that order).
+ **
+ **
+ ** <STRONG>Properties:</STRONG><P>
+ **
+ ** <OL>
+ ** <LI>If there is a <CODE>public boolean isXXX()</CODE>
+ ** method, then XXX is a read-only boolean property.
+ ** <CODE>boolean getXXX()</CODE> may be supplied in
+ ** addition to this method, although isXXX() is the
+ ** one that will be used in this case and getXXX()
+ ** will be ignored. If there is a
+ ** <CODE>public void setXXX(boolean)</CODE> method,
+ ** it is part of this group and makes it a read-write
+ ** property.</LI>
+ ** <LI>If there is a
+ ** <CODE>public &lt;type&gt; getXXX(int)</CODE>
+ ** method, then XXX is a read-only indexed property of
+ ** type &lt;type&gt;. If there is a
+ ** <CODE>public void setXXX(int,&lt;type&gt;)</CODE>
+ ** method, then it is a read-write indexed property of
+ ** type &lt;type&gt;. There may also be a
+ ** <CODE>public &lt;type&gt;[] getXXX()</CODE> and a
+ ** <CODE>public void setXXX(&lt;type&gt;)</CODE>
+ ** method as well.</CODE></LI>
+ ** <LI>If there is a
+ ** <CODE>public void setXXX(int,&lt;type&gt;)</CODE>
+ ** method, then it is a write-only indexed property of
+ ** type &lt;type&gt;. There may also be a
+ ** <CODE>public &lt;type&gt;[] getXXX()</CODE> and a
+ ** <CODE>public void setXXX(&lt;type&gt;)</CODE>
+ ** method as well.</CODE></LI>
+ ** <LI>If there is a
+ ** <CODE>public &lt;type&gt; getXXX()</CODE> method,
+ ** then XXX is a read-only property of type
+ ** &lt;type&gt;. If there is a
+ ** <CODE>public void setXXX(&lt;type&gt;)</CODE>
+ ** method, then it will be used for the property and
+ ** the property will be considered read-write.</LI>
+ ** <LI>If there is a
+ ** <CODE>public void setXXX(&lt;type&gt;)</CODE>
+ ** method, then as long as XXX is not already used as
+ ** the name of a property, XXX is assumed to be a
+ ** write-only property of type &lt;type&gt;.</LI>
+ ** <LI>In all of the above cases, if the setXXX() method
+ ** throws <CODE>PropertyVetoException</CODE>, then the
+ ** property in question is assumed to be constrained.
+ ** No properties are ever assumed to be bound
+ ** (<STRONG>Spec Note:</STRONG> this is not in the
+ ** spec, it just makes sense). See PropertyDescriptor
+ ** for a description of bound and constrained
+ ** properties.</LI>
+ ** </OL>
+ **
+ ** <STRONG>Events:</STRONG><P>
+ **
+ ** If there is a pair of methods,
+ ** <CODE>public void addXXX(&lt;type&gt;)</CODE> and
+ ** <CODE>public void removeXXX(&lt;type&gt;)</CODE>, where
+ ** &lt;type&gt; is a descendant of
+ ** <CODE>java.util.EventListener</CODE>, then the pair of
+ ** methods imply that this Bean will fire events to
+ ** listeners of type &lt;type&gt;.<P>
+ **
+ ** If the addXXX() method throws
+ ** <CODE>java.util.TooManyListenersException</CODE>, then
+ ** the event set is assumed to be <EM>unicast</EM>. See
+ ** EventSetDescriptor for a discussion of unicast event
+ ** sets.<P>
+ **
+ ** <STRONG>Spec Note:</STRONG> the spec seems to say that
+ ** the listener type's classname must be equal to the XXX
+ ** part of addXXX() and removeXXX(), but that is not the
+ ** case in Sun's implementation, so I am assuming it is
+ ** not the case in general.<P>
+ **
+ ** <STRONG>Methods:</STRONG><P>
+ **
+ ** Any public methods (including those which were used
+ ** for Properties or Events) are used as Methods.
+ **
+ ** @author John Keiser
+ ** @since JDK1.1
+ ** @version 1.1.0, 29 Jul 1998
+ ** @see java.beans.BeanInfo
+ **/
+
+public class Introspector {
+ static String[] beanInfoSearchPath = {"gnu.java.beans.info", "sun.beans.infos"};
+ static Hashtable beanInfoCache = new Hashtable();
+
+ private Introspector() {}
+
+ /** Get the BeanInfo for class <CODE>beanClass</CODE>,
+ ** first by looking for explicit information, next by
+ ** using standard design patterns to determine
+ ** information about the class.
+ ** @param beanClass the class to get BeanInfo about.
+ ** @return the BeanInfo object representing the class.
+ **/
+ public static BeanInfo getBeanInfo(Class beanClass) throws IntrospectionException {
+ BeanInfo cachedInfo;
+ synchronized(beanClass) {
+ cachedInfo = (BeanInfo)beanInfoCache.get(beanClass);
+ if(cachedInfo != null) {
+ return cachedInfo;
+ }
+ cachedInfo = getBeanInfo(beanClass,null);
+ beanInfoCache.put(beanClass,cachedInfo);
+ return cachedInfo;
+ }
+ }
+
+ /** Get the BeanInfo for class <CODE>beanClass</CODE>,
+ ** first by looking for explicit information, next by
+ ** using standard design patterns to determine
+ ** information about the class. It crawls up the
+ ** inheritance tree until it hits <CODE>topClass</CODE>.
+ ** @param beanClass the Bean class.
+ ** @param stopClass the class to stop at.
+ ** @return the BeanInfo object representing the class.
+ **/
+ public static BeanInfo getBeanInfo(Class beanClass, Class stopClass) throws IntrospectionException {
+ ExplicitInfo explicit = new ExplicitInfo(beanClass,stopClass);
+
+ IntrospectionIncubator ii = new IntrospectionIncubator();
+ ii.setPropertyStopClass(explicit.propertyStopClass);
+ ii.setEventStopClass(explicit.eventStopClass);
+ ii.setMethodStopClass(explicit.methodStopClass);
+ ii.addMethods(beanClass.getMethods());
+
+ BeanInfoEmbryo currentInfo = ii.getBeanInfoEmbryo();
+ PropertyDescriptor[] p = explicit.explicitPropertyDescriptors;
+ if(p!=null) {
+ for(int i=0;i<p.length;i++) {
+ if(!currentInfo.hasProperty(p[i])) {
+ currentInfo.addProperty(p[i]);
+ }
+ }
+ if(explicit.defaultProperty != -1) {
+ currentInfo.setDefaultPropertyName(p[explicit.defaultProperty].getName());
+ }
+ }
+ EventSetDescriptor[] e = explicit.explicitEventSetDescriptors;
+ if(e!=null) {
+ for(int i=0;i<e.length;i++) {
+ if(!currentInfo.hasEvent(e[i])) {
+ currentInfo.addEvent(e[i]);
+ }
+ }
+ if(explicit.defaultEvent != -1) {
+ currentInfo.setDefaultEventName(e[explicit.defaultEvent].getName());
+ }
+ }
+ MethodDescriptor[] m = explicit.explicitMethodDescriptors;
+ if(m!=null) {
+ for(int i=0;i<m.length;i++) {
+ if(!currentInfo.hasMethod(m[i])) {
+ currentInfo.addMethod(m[i]);
+ }
+ }
+ }
+
+ if(explicit.explicitBeanDescriptor != null) {
+ currentInfo.setBeanDescriptor(new BeanDescriptor(beanClass,explicit.explicitBeanDescriptor.getCustomizerClass()));
+ } else {
+ currentInfo.setBeanDescriptor(new BeanDescriptor(beanClass,null));
+ }
+
+ currentInfo.setAdditionalBeanInfo(explicit.explicitBeanInfo);
+ currentInfo.setIcons(explicit.im);
+
+ return currentInfo.getBeanInfo();
+ }
+
+ /** Get the search path for BeanInfo classes.
+ ** @return the BeanInfo search path.
+ **/
+ public static String[] getBeanInfoSearchPath() {
+ return beanInfoSearchPath;
+ }
+
+ /** Set the search path for BeanInfo classes.
+ ** @param beanInfoSearchPath the new BeanInfo search
+ ** path.
+ **/
+ public static void setBeanInfoSearchPath(String[] beanInfoSearchPath) {
+ Introspector.beanInfoSearchPath = beanInfoSearchPath;
+ }
+
+ /** A helper method to convert a name to standard Java
+ ** naming conventions: anything with two capitals as the
+ ** first two letters remains the same, otherwise the
+ ** first letter is decapitalized. URL = URL, I = i,
+ ** MyMethod = myMethod.
+ ** @param name the name to decapitalize.
+ ** @return the decapitalized name.
+ **/
+ public static String decapitalize(String name) {
+ try {
+ if(!Character.isUpperCase(name.charAt(0))) {
+ return name;
+ } else {
+ try {
+ if(Character.isUpperCase(name.charAt(1))) {
+ return name;
+ } else {
+ char[] c = name.toCharArray();
+ c[0] = Character.toLowerCase(c[0]);
+ return new String(c);
+ }
+ } catch(StringIndexOutOfBoundsException E) {
+ char[] c = new char[1];
+ c[0] = Character.toLowerCase(name.charAt(0));
+ return new String(c);
+ }
+ }
+ } catch(StringIndexOutOfBoundsException E) {
+ return name;
+ } catch(NullPointerException E) {
+ return null;
+ }
+ }
+
+ static BeanInfo copyBeanInfo(BeanInfo b) {
+ java.awt.Image[] icons = new java.awt.Image[4];
+ for(int i=1;i<=4;i++) {
+ icons[i-1] = b.getIcon(i);
+ }
+ return new ExplicitBeanInfo(b.getBeanDescriptor(),b.getAdditionalBeanInfo(),
+ b.getPropertyDescriptors(),b.getDefaultPropertyIndex(),
+ b.getEventSetDescriptors(),b.getDefaultEventIndex(),
+ b.getMethodDescriptors(),icons);
+ }
+}
+
+class ExplicitInfo {
+ BeanDescriptor explicitBeanDescriptor;
+ BeanInfo[] explicitBeanInfo;
+
+ PropertyDescriptor[] explicitPropertyDescriptors;
+ EventSetDescriptor[] explicitEventSetDescriptors;
+ MethodDescriptor[] explicitMethodDescriptors;
+
+ int defaultProperty;
+ int defaultEvent;
+
+ java.awt.Image[] im = new java.awt.Image[4];
+
+ Class propertyStopClass;
+ Class eventStopClass;
+ Class methodStopClass;
+
+ ExplicitInfo(Class beanClass, Class stopClass) {
+ while(beanClass != null && !beanClass.equals(stopClass)) {
+ BeanInfo explicit = findExplicitBeanInfo(beanClass);
+ if(explicit != null) {
+ if(explicitBeanDescriptor == null) {
+ explicitBeanDescriptor = explicit.getBeanDescriptor();
+ }
+ if(explicitBeanInfo == null) {
+ explicitBeanInfo = explicit.getAdditionalBeanInfo();
+ }
+ if(explicitPropertyDescriptors == null) {
+ if(explicit.getPropertyDescriptors() != null) {
+ explicitPropertyDescriptors = explicit.getPropertyDescriptors();
+ defaultProperty = explicit.getDefaultPropertyIndex();
+ propertyStopClass = beanClass;
+ }
+ }
+ if(explicitEventSetDescriptors == null) {
+ if(explicit.getEventSetDescriptors() != null) {
+ explicitEventSetDescriptors = explicit.getEventSetDescriptors();
+ defaultEvent = explicit.getDefaultEventIndex();
+ eventStopClass = beanClass;
+ }
+ }
+ if(explicitMethodDescriptors == null) {
+ if(explicit.getMethodDescriptors() != null) {
+ explicitMethodDescriptors = explicit.getMethodDescriptors();
+ methodStopClass = beanClass;
+ }
+ }
+ if(im[0] == null
+ && im[1] == null
+ && im[2] == null
+ && im[3] == null) {
+ im[0] = explicit.getIcon(0);
+ im[1] = explicit.getIcon(1);
+ im[2] = explicit.getIcon(2);
+ im[3] = explicit.getIcon(3);
+ }
+ }
+ beanClass = beanClass.getSuperclass();
+ }
+ if(propertyStopClass == null) {
+ propertyStopClass = stopClass;
+ }
+ if(eventStopClass == null) {
+ eventStopClass = stopClass;
+ }
+ if(methodStopClass == null) {
+ methodStopClass = stopClass;
+ }
+ }
+
+ static Hashtable explicitBeanInfos = new Hashtable();
+ static Vector emptyBeanInfos = new Vector();
+
+ static BeanInfo findExplicitBeanInfo(Class beanClass) {
+ BeanInfo retval = (BeanInfo)explicitBeanInfos.get(beanClass);
+ if(retval != null) {
+ return retval;
+ } else if(emptyBeanInfos.indexOf(beanClass) != -1) {
+ return null;
+ } else {
+ retval = reallyFindExplicitBeanInfo(beanClass);
+ if(retval != null) {
+ explicitBeanInfos.put(beanClass,retval);
+ } else {
+ emptyBeanInfos.addElement(beanClass);
+ }
+ return retval;
+ }
+ }
+
+ static BeanInfo reallyFindExplicitBeanInfo(Class beanClass) {
+ try {
+ try {
+ return (BeanInfo)Class.forName(beanClass.getName()+"BeanInfo").newInstance();
+ } catch(ClassNotFoundException E) {
+ }
+ String newName = ClassHelper.getTruncatedClassName(beanClass) + "BeanInfo";
+ for(int i=0;i<Introspector.beanInfoSearchPath.length;i++) {
+ try {
+ if(Introspector.beanInfoSearchPath[i].equals("")) {
+ return (BeanInfo)Class.forName(newName).newInstance();
+ } else {
+ return (BeanInfo)Class.forName(Introspector.beanInfoSearchPath[i] + "." + newName).newInstance();
+ }
+ } catch(ClassNotFoundException E) {
+ }
+ }
+ } catch(IllegalAccessException E) {
+ } catch(InstantiationException E) {
+ }
+ return null;
+ }
+}