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Posted to dev@struts.apache.org by cr...@locus.apache.org on 2000/08/29 02:42:25 UTC
cvs commit: jakarta-struts/src/share/org/apache/struts/util PropertyUtils.java
craigmcc 00/08/28 17:42:25
Added: src/share/org/apache/struts/util PropertyUtils.java
Log:
Initial commit of new PropertyUtils module that knows how to deal with
simple, nested (x.y.z) and indexed (a[3]) references to properties. Not
thoroughly tested yet, but will be utilized in the new set of tags focused
on creating page-scope beans from a variety of sources.
Revision Changes Path
1.1 jakarta-struts/src/share/org/apache/struts/util/PropertyUtils.java
Index: PropertyUtils.java
===================================================================
/*
* $Header: /home/cvs/jakarta-struts/src/share/org/apache/struts/util/PropertyUtils.java,v 1.1 2000/08/29 00:42:24 craigmcc Exp $
* $Revision: 1.1 $
* $Date: 2000/08/29 00:42:24 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.struts.util;
import java.beans.BeanInfo;
import java.beans.IndexedPropertyDescriptor;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Hashtable;
/**
* Utility methods for using Java Reflection APIs to facilitate generic
* property getter and setter operations on Java objects. Much of this
* code was originally included in <code>BeanUtils</code>, but has been
* separated because of the volume of code involved.
* <p>
* In general, the objects that are examined and modified using these
* methods are expected to conform to the property getter and setter method
* naming conventions described in the JavaBeans Specification (Version 1.0.1).
* No data type conversions are performed, and there are no usage of any
* <code>PropertyEditor</code> classes that have been registered, although
* a convenient way to access the registered classes themselves is included.
* <p>
* For the purposes of this class, three formats for referencing a particular
* property value of a bean are defined, with the layout of an identifying
* String in parentheses:
* <ul>
* <li><strong>Simple (<code>name</code>)</strong> - The specified
* <code>name</code> identifies an individual property of a particular
* JavaBean. The name of the actual getter or setter method to be used
* is determined using standard JavaBeans instrospection, so that (unless
* overridden by a <code>BeanInfo</code> class, a property named "xyz"
* will have a getter method named <code>getXyz()</code> or (for boolean
* properties only) <code>isXyz()</code>, and a setter method named
* <code>setXyz()</code>.</li>
* <li><strong>Nested (<code>name1.name2.name3</code>)</strong> The first
* name element is used to select a property getter, as for simple
* references above. The object returned for this property is then
* consulted, using the same approach, for a property getter for a
* property named <code>name2</code>, and so on. The property value that
* is ultimately retrieved or modified is the one identified by the
* last name element.</li>
* <li><strong>Indexed (<code>name[index]</code>)</strong> - The underlying
* property value is assumed to be an array, or this JavaBean is assumed
* to have indexed property getter and setter methods. The appropriate
* (zero-relative) entry in the array is selected.</li>
* </ul>
*
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
* @version $Revision: 1.1 $ $Date: 2000/08/29 00:42:24 $
*/
public final class PropertyUtils {
// ------------------------------------------------------- Static Variables
/**
* The cache of PropertyDescriptor arrays for beans we have already
* introspected, keyed by the fully qualified class name of this object.
*/
private static Hashtable descriptorsCache = new Hashtable();
// --------------------------------------------------------- Public Methods
/**
* Copy property values from the "origin" bean to the "destination" bean
* for all cases where the property names are the same (even though the
* actual getter and setter methods might have been customized via
* <code>BeanInfo</code> classes). No conversions are performed on the
* actual property values -- it is assumed that the values retrieved from
* the origin bean are assignment-compatible with the types expected by
* the destination bean.
*
* @param dest Destination bean whose properties are modified
* @param orig Origin bean whose properties are retrieved
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void copyProperties(Object dest, Object orig)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
PropertyDescriptor origDescriptors[] = getPropertyDescriptors(orig);
for (int i = 0; i < origDescriptors.length; i++) {
String name = origDescriptors[i].getName();
if (getPropertyDescriptor(dest, name) != null) {
Object value = getSimpleProperty(orig, name);
setSimpleProperty(dest, name, value);
}
}
}
/**
* Return the value of the specified indexed property of the specified
* bean, with no type conversions. The zero-relative index of the
* required value must be included (in square brackets) as a suffix to
* the property name, or <code>IllegalArgumentException</code> will be
* thrown.
*
* @param bean Bean whose property is to be extracted
* @param name <code>propertyname[index]</code> of the property value
* to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Object getIndexedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Identify the index of the requested individual property
int left = name.indexOf("[");
int right = name.indexOf("]");
if ((left < 0) || (right <= left))
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
if (right > (name.length() - 1))
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
int index = -1;
try {
String subscript = name.substring(left + 1, right);
index = Integer.parseInt(subscript);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
}
name = name.substring(0, left);
// Request the specified indexed property value
return (getIndexedProperty(bean, name, index));
}
/**
* Return the value of the specified indexed property of the specified
* bean, with no type conversions.
*
* @param bean Bean whose property is to be extracted
* @param name Simple property name of the property value to be extracted
* @param index Index of the property value to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Object getIndexedProperty(Object bean,
String name, int index)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Retrieve the property descriptor for the specified property
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor == null)
throw new NoSuchMethodException("Unknown property '" +
name + "'");
// Call the indexed getter method if there is one
if (descriptor instanceof IndexedPropertyDescriptor) {
Method readMethod = ((IndexedPropertyDescriptor) descriptor).
getIndexedReadMethod();
if (readMethod != null) {
Object subscript[] = new Object[1];
subscript[0] = new Integer(index);
return (readMethod.invoke(bean, subscript));
}
}
// Otherwise, the underlying property must be an array
Method readMethod = descriptor.getReadMethod();
if (readMethod == null)
throw new NoSuchMethodException("Property '" + name +
"' has no getter method");
// Call the property getter and return the value
Object value = readMethod.invoke(bean, new Object[0]);
if (!value.getClass().isArray())
throw new IllegalArgumentException("Property '" + name +
"' is not indexed");
return (Array.get(value, index));
}
/**
* Return the value of the (possibly nested) property of the specified
* name, for the specified bean, with no type conversions.
*
* @param bean Bean whose property is to be extracted
* @param name Possibly nested name of the property to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Object getNestedProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
while (true) {
int period = name.indexOf(".");
if (period < 0)
break;
String next = name.substring(0, period);
if (next.indexOf("[") >= 0)
bean = getIndexedProperty(bean, next);
else
bean = getSimpleProperty(bean, next);
if (bean == null)
throw new IllegalArgumentException
("Null property value for '" +
name.substring(0, period) + "'");
name = name.substring(period + 1);
}
if (name.indexOf("[") >= 0)
return (getIndexedProperty(bean, name));
else
return (getSimpleProperty(bean, name));
}
/**
* Return the value of the specified property of the specified bean,
* no matter which property reference format is used, with no
* type conversions.
*
* @param bean Bean whose property is to be extracted
* @param name Possibly indexed and/or nested name of the property
* to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Object getProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
return (getNestedProperty(bean, name));
}
/**
* Retrieve the property descriptor for the specified property of the
* specified bean, or return <code>null</code> if there is no such
* descriptor. This method resolves indexed and nested property
* references in the same manner as other methods in this class, except
* that if the last (or only) name element is indexed, the descriptor
* for the property itself is returned.
*
* @param bean Bean for which a property descriptor is requested
* @param name Possibly indexed and/or nested name of the property for
* which a property descriptor is requested
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static PropertyDescriptor getPropertyDescriptor(Object bean,
String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Resolve nested references
while (true) {
int period = name.indexOf(".");
if (period < 0)
break;
String next = name.substring(0, period);
if (next.indexOf("[") >= 0)
bean = getIndexedProperty(bean, next);
else
bean = getSimpleProperty(bean, next);
if (bean == null)
throw new IllegalArgumentException
("Null property value for '" +
name.substring(0, period) + "'");
name = name.substring(period + 1);
}
// Remove any subscript from the final name value
int left = name.indexOf("[");
if (left >= 0)
name = name.substring(0, left);
// Look up and return this property from our cache
if ((bean == null) || (name == null))
return (null);
PropertyDescriptor descriptors[] = getPropertyDescriptors(bean);
if (descriptors == null)
return (null);
for (int i = 0; i < descriptors.length; i++) {
if (name.equals(descriptors[i].getName()))
return (descriptors[i]);
}
return (null);
}
/**
* Retrieve the property descriptors for the specified bean, introspecting
* and caching them the first time a particular bean class is encountered.
*
* @param bean Bean for which property descriptors are requested
*/
public static PropertyDescriptor[] getPropertyDescriptors(Object bean) {
if (bean == null)
return (new PropertyDescriptor[0]);
// Look up any cached descriptors for this bean class
String beanClassName = bean.getClass().getName();
PropertyDescriptor descriptors[] =
(PropertyDescriptor[]) descriptorsCache.get(beanClassName);
if (descriptors != null)
return (descriptors);
// Introspect the bean and cache the generated descriptors
BeanInfo beanInfo = null;
try {
beanInfo = Introspector.getBeanInfo(bean.getClass());
} catch (IntrospectionException e) {
return (new PropertyDescriptor[0]);
}
descriptors = beanInfo.getPropertyDescriptors();
if (descriptors == null)
descriptors = new PropertyDescriptor[0];
descriptorsCache.put(beanClassName, descriptors);
return (descriptors);
}
/**
* Return the Java Class repesenting the property editor class that has
* been registered for this property (if any). This method follows the
* same name resolution rules used by <code>getPropertyDescriptor()</code>,
* so if the last element of a name reference is indexed, the property
* editor for the underlying property's class is returned.
* <p>
* Note that <code>null</code> will be returned if there is no property,
* or if there is no registered property editor class. Because this
* return value is ambiguous, you should determine the existence of the
* property itself by other means.
*
* @param bean Bean for which a property descriptor is requested
* @param name Possibly indexed and/or nested name of the property for
* which a property descriptor is requested
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Class getPropertyEditorClass(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor != null)
return (descriptor.getPropertyEditorClass());
else
return (null);
}
/**
* Return the Java Class repesenting the property type of the specified
* property, or <code>null</code> if there is no such property for the
* specified bean. This method follows the same name resolution rules
* used by <code>getPropertyDescriptor()</code>, so if the last element
* of a name reference is indexed, the type of the property itself will
* be returned. If the last (or only) element has no property with the
* specified name, <code>null</code> is returned.
*
* @param bean Bean for which a property descriptor is requested
* @param name Possibly indexed and/or nested name of the property for
* which a property descriptor is requested
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Class getPropertyType(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor != null)
return (descriptor.getPropertyType());
else
return (null);
}
/**
* Return the value of the specified simple property of the specified
* bean, with no type conversions.
*
* @param bean Bean whose property is to be extracted
* @param name Name of the property to be extracted
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static Object getSimpleProperty(Object bean, String name)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Retrieve the property getter method for the specified property
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor == null)
throw new NoSuchMethodException("Unknown property '" +
name + "'");
Method readMethod = descriptor.getReadMethod();
if (readMethod == null)
throw new NoSuchMethodException("Property '" + name +
"' has no getter method");
// Call the property getter and return the value
Object value = readMethod.invoke(bean, new Object[0]);
return (value);
}
/**
* Set the value of the (possibly nested) property of the specified
* name, for the specified bean, with no type conversions.
*
* @param bean Bean whose property is to be modified
* @param name Possibly nested name of the property to be modified
* @param value Value to which the property is to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception IllegalArgumentException if a nested reference to a
* property returns null
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void setNestedProperty(Object bean,
String name, Object value)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
while (true) {
int period = name.indexOf(".");
if (period < 0)
break;
String next = name.substring(0, period);
if (next.indexOf("[") >= 0)
bean = getIndexedProperty(bean, next);
else
bean = getSimpleProperty(bean, next);
if (bean == null)
throw new IllegalArgumentException
("Null property value for '" +
name.substring(0, period) + "'");
name = name.substring(period + 1);
}
if (name.indexOf("[") >= 0)
setIndexedProperty(bean, name, value);
else
setSimpleProperty(bean, name, value);
}
/**
* Set the value of the specified indexed property of the specified
* bean, with no type conversions. The zero-relative index of the
* required value must be included (in square brackets) as a suffix to
* the property name, or <code>IllegalArgumentException</code> will be
* thrown.
*
* @param bean Bean whose property is to be modified
* @param name <code>propertyname[index]</code> of the property value
* to be modified
* @param value Value to which the specified property element
* should be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void setIndexedProperty(Object bean, String name,
Object value)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Identify the index of the requested individual property
int left = name.indexOf("[");
int right = name.indexOf("]");
if ((left < 0) || (right <= left))
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
if (right > (name.length() - 1))
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
int index = -1;
try {
String subscript = name.substring(left + 1, right);
index = Integer.parseInt(subscript);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Invalid indexed property '" +
name + "'");
}
name = name.substring(0, left);
// Request the specified indexed property value
setIndexedProperty(bean, name, index, value);
}
/**
* Set the value of the specified indexed property of the specified
* bean, with no type conversions.
*
* @param bean Bean whose property is to be set
* @param name Simple property name of the property value to be set
* @param index Index of the property value to be set
* @param value Value to which the indexed property element is to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void setIndexedProperty(Object bean, String name,
int index, Object value)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Retrieve the property descriptor for the specified property
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor == null)
throw new NoSuchMethodException("Unknown property '" +
name + "'");
// Call the indexed setter method if there is one
if (descriptor instanceof IndexedPropertyDescriptor) {
Method writeMethod = ((IndexedPropertyDescriptor) descriptor).
getIndexedWriteMethod();
if (writeMethod != null) {
Object subscript[] = new Object[2];
subscript[0] = new Integer(index);
subscript[1] = value;
writeMethod.invoke(bean, subscript);
}
}
// Otherwise, the underlying property must be an array
Method readMethod = descriptor.getReadMethod();
if (readMethod == null)
throw new NoSuchMethodException("Property '" + name +
"' has no getter method");
// Call the property getter to get the array
Object array = readMethod.invoke(bean, new Object[0]);
if (!array.getClass().isArray())
throw new IllegalArgumentException("Property '" + name +
"' is not indexed");
// Modify the specified value
Array.set(array, index, value);
}
/**
* Set the value of the specified property of the specified bean,
* no matter which property reference format is used, with no
* type conversions.
*
* @param bean Bean whose property is to be modified
* @param name Possibly indexed and/or nested name of the property
* to be modified
* @param value Value to which this property is to be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void setProperty(Object bean, String name, Object value)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
setNestedProperty(bean, name, value);
}
/**
* Set the value of the specified simple property of the specified bean,
* with no type conversions.
*
* @param bean Bean whose property is to be modified
* @param name Name of the property to be modified
* @param value Value to which the property should be set
*
* @exception IllegalAccessException if the caller does not have
* access to the property accessor method
* @exception InvocationTargetException if the property accessor method
* throws an exception
* @exception NoSuchMethodException if an accessor method for this
* propety cannot be found
*/
public static void setSimpleProperty(Object bean,
String name, Object value)
throws IllegalAccessException, InvocationTargetException,
NoSuchMethodException {
// Retrieve the property setter method for the specified property
PropertyDescriptor descriptor =
getPropertyDescriptor(bean, name);
if (descriptor == null)
throw new NoSuchMethodException("Unknown property '" +
name + "'");
Method writeMethod = descriptor.getWriteMethod();
if (writeMethod == null)
throw new NoSuchMethodException("Property '" + name +
"' has no setter method");
// Call the property setter method
Object values[] = new Object[1];
values[0] = value;
writeMethod.invoke(bean, values);
}
}