propertydescriptor.java

gcc的组建

/* java.beans.PropertyDescriptor
   Copyright (C) 1998, 2001, 2004, 2005  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
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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.beans;

import java.lang.reflect.Method;

/**
 ** PropertyDescriptor describes information about a JavaBean property,
 ** by which we mean a property that has been exposed via a pair of
 ** get and set methods.  (There may be no get method, which means
 ** the property is write-only, or no set method, which means the
 ** the property is read-only.)<P>
 **
 ** The constraints put on get and set methods are:<P>
 ** <OL>
 ** <LI>A get method must have signature
 **     <CODE>&lt;propertyType&gt; &lt;getMethodName&gt;()</CODE></LI>
 ** <LI>A set method must have signature
 **     <CODE>void &lt;setMethodName&gt;(&lt;propertyType&gt;)</CODE></LI>
 ** <LI>Either method type may throw any exception.</LI>
 ** <LI>Both methods must be public.</LI>
 ** </OL>
 **
 ** @author John Keiser
 ** @author Robert Schuster ([e-mail])
 ** @since 1.1
 ** @status updated to 1.4
 **/
public class PropertyDescriptor extends FeatureDescriptor
{
    Class propertyType;
    Method getMethod;
    Method setMethod;

    Class propertyEditorClass;
    boolean bound;
    boolean constrained;

    PropertyDescriptor(String name)
    {
        setName(name);
    }

    /** Create a new PropertyDescriptor by introspection.
     ** This form of constructor creates the PropertyDescriptor by
     ** looking for a getter method named <CODE>get&lt;name&gt;()</CODE>
     ** (or, optionally, if the property is boolean,
     ** <CODE>is&lt;name&gt;()</CODE>) and
     ** <CODE>set&lt;name&gt;()</CODE> in class
     ** <CODE>&lt;beanClass&gt;</CODE>, where &lt;name&gt; has its
     ** first letter capitalized by the constructor.<P>
     **
     ** Note that using this constructor the given property must be read- <strong>and</strong>
     ** writeable. If the implementation does not both, a read and a write method, an
     ** <code>IntrospectionException</code> is thrown.
     **
     ** <B>Implementation note:</B> If there is both are both isXXX and
     ** getXXX methods, the former is used in preference to the latter.
     ** We do not check that an isXXX method returns a boolean. In both
     ** cases, this matches the behaviour of JDK 1.4<P>
     **
     ** @param name the programmatic name of the property, usually
     **             starting with a lowercase letter (e.g. fooManChu
     **             instead of FooManChu).
     ** @param beanClass the class the get and set methods live in.
     ** @exception IntrospectionException if the methods are not found 
     **            or invalid.
     **/
    public PropertyDescriptor(String name, Class beanClass)
        throws IntrospectionException
    {
        setName(name);
        if (name.length() == 0)
        {
            throw new IntrospectionException("empty property name");
        }
        String caps = Character.toUpperCase(name.charAt(0)) + name.substring(1);
        findMethods(beanClass, "is" + caps, "get" + caps, "set" + caps);

        if (getMethod == null)
        {
            throw new IntrospectionException(
                "Cannot find a is" + caps + " or get" + caps + " method");
        }

        if (setMethod == null)
        {
            throw new IntrospectionException(
                "Cannot find a " + caps + " method");
        }

        // finally check the methods compatibility        
        propertyType = checkMethods(getMethod, setMethod);
    }

    /** Create a new PropertyDescriptor by introspection.
     ** This form of constructor allows you to specify the
     ** names of the get and set methods to search for.<P>
     **
     ** <B>Implementation note:</B> If there is a get method (or
     ** boolean isXXX() method), then the return type of that method
     ** is used to find the set method.  If there is no get method,
     ** then the set method is searched for exhaustively.<P>
     **
     ** <B>Spec note:</B>
     ** If there is no get method and multiple set methods with
     ** the same name and a single parameter (different type of course),
     ** then an IntrospectionException is thrown.  While Sun's spec
     ** does not state this, it can make Bean behavior different on
     ** different systems (since method order is not guaranteed) and as
     ** such, can be treated as a bug in the spec.  I am not aware of
     ** whether Sun's implementation catches this.
     **
     ** @param name the programmatic name of the property, usually
     **             starting with a lowercase letter (e.g. fooManChu
     **             instead of FooManChu).
     ** @param beanClass the class the get and set methods live in.
     ** @param getMethodName the name of the get method or <code>null</code> if the property is write-only.
     ** @param setMethodName the name of the set method or <code>null</code> if the property is read-only.
     ** @exception IntrospectionException if the methods are not found 
     **            or invalid.
     **/
    public PropertyDescriptor(
        String name,
        Class beanClass,
        String getMethodName,
        String setMethodName)
        throws IntrospectionException
    {
        setName(name);
        findMethods(beanClass, getMethodName, null, setMethodName);

        if (getMethod == null && getMethodName != null)
        {
            throw new IntrospectionException(
                "Cannot find a getter method called " + getMethodName);
        }

        if (setMethod == null && setMethodName != null)
        {
            throw new IntrospectionException(
                "Cannot find a setter method called " + setMethodName);
        }

        propertyType = checkMethods(getMethod, setMethod);
    }

    /** Create a new PropertyDescriptor using explicit Methods.
     ** Note that the methods will be checked for conformance to standard
     ** Property method rules, as described above at the top of this class.
     **<br>
     ** It is possible to call this method with both <code>Method</code> arguments
     ** being <code>null</code>. In such a case the property type is <code>null</code>.
     ** 
     ** @param name the programmatic name of the property, usually
     **             starting with a lowercase letter (e.g. fooManChu
     **             instead of FooManChu).
     ** @param readMethod the read method or <code>null</code> if the property is write-only.
     ** @param writeMethod the write method or <code>null</code> if the property is read-only.
     ** @exception IntrospectionException if the methods are not found 
     **            or invalid.
     **/
    public PropertyDescriptor(
        String name,
        Method readMethod,
        Method writeMethod)
        throws IntrospectionException
    {
        setName(name);
        getMethod = readMethod;
        setMethod = writeMethod;
        propertyType = checkMethods(getMethod, setMethod);
    }

    /** Get the property type.
     ** This is the type the get method returns and the set method
     ** takes in.
     **/
    public Class getPropertyType()
    {
        return propertyType;
    }

    /** Get the get method.  Why they call it readMethod here and
     ** get everywhere else is beyond me.
     **/
    public Method getReadMethod()
    {
        return getMethod;
    }

    /** Sets the read method.<br/>
     * The read method is used to retrieve the value of a property. A legal
     * read method must have no arguments. Its return type must not be
     * <code>void</code>. If this methods succeeds the property type
     * is adjusted to the return type of the read method.<br/>
     * <br/>
     * It is legal to set the read and the write method to <code>null</code>
     * or provide method which have been declared in distinct classes.
     * 
     * @param readMethod The new method to be used or <code>null</code>.
     * @throws IntrospectionException If the given method is invalid.
     * @since 1.2
     */
    public void setReadMethod(Method readMethod) throws IntrospectionException
    {
        propertyType = checkMethods(readMethod, setMethod);

        getMethod = readMethod;
    }

    /** Get the set method.  Why they call it writeMethod here and
     ** set everywhere else is beyond me.
     **/
    public Method getWriteMethod()
    {
        return setMethod;
    }

    /** Sets the write method.<br/>
     * The write method is used to set the value of a property. A legal write method
     * must have a single argument which can be assigned to the property. If no
     * read method exists the property type changes to the argument type of the
     * write method.<br/>
     * <br/>
     * It is legal to set the read and the write method to <code>null</code>
     * or provide method which have been declared in distinct classes.
     * 
     * @param writeMethod The new method to be used or <code>null</code>.
     * @throws IntrospectionException If the given method is invalid.
     * @since 1.2
     */
    public void setWriteMethod(Method writeMethod)
        throws IntrospectionException
    {
        propertyType = checkMethods(getMethod, writeMethod);

        setMethod = writeMethod;
    }

    /** Get whether the property is bound.  Defaults to false. **/
    public boolean isBound()
    {
        return bound;
    }

    /** Set whether the property is bound.
     ** As long as the the bean implements addPropertyChangeListener() and
     ** removePropertyChangeListener(), setBound(true) may safely be called.<P>
     ** If these things are not true, then the behavior of the system
     ** will be undefined.<P>
     **
     ** When a property is bound, its set method is required to fire the
     ** <CODE>PropertyChangeListener.propertyChange())</CODE> event
     ** after the value has changed.
     ** @param bound whether the property is bound or not.
     **/
    public void setBound(boolean bound)
    {
        this.bound = bound;
    }

    /** Get whether the property is constrained.  Defaults to false. **/
    public boolean isConstrained()
    {