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XWork is an command-pattern framework that is used to power WebWork
as well as other applications. XWork provides an Inversion of Control
container, a powerful expression language, data type conversion,
validation, and pluggable configuration.
/*
* Copyright (c) 2002-2006 by OpenSymphony
* All rights reserved.
*/
package com.opensymphony.xwork2.util;
import ognl.Ognl;
import ognl.OgnlContext;
import ognl.OgnlException;
import ognl.OgnlRuntime;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.opensymphony.xwork2.XWorkException;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* Utility class that provides common access to the Ognl APIs for
* setting and getting properties from objects (usually Actions).
*
* @author Jason Carreira
*/
public class OgnlUtil {
private static final Log log = LogFactory.getLog(OgnlUtil.class);
private static HashMap expressions = new HashMap();
private static HashMap beanInfoCache = new HashMap();
/**
* Sets the object's properties using the default type converter, defaulting to not throw
* exceptions for problems setting the properties.
*
* @param props the properties being set
* @param o the object
* @param context the action context
*/
public static void setProperties(Map props, Object o, Map context) {
setProperties(props, o, context, false);
}
/**
* Sets the object's properties using the default type converter.
*
* @param props the properties being set
* @param o the object
* @param context the action context
* @param throwPropertyExceptions boolean which tells whether it should throw exceptions for
* problems setting the properties
*/
public static void setProperties(Map props, Object o, Map context, boolean throwPropertyExceptions) {
if (props == null) {
return;
}
Ognl.setTypeConverter(context, XWorkConverter.getInstance());
Object oldRoot = Ognl.getRoot(context);
Ognl.setRoot(context, o);
for (Iterator iterator = props.entrySet().iterator();
iterator.hasNext();) {
Map.Entry entry = (Map.Entry) iterator.next();
String expression = (String) entry.getKey();
internalSetProperty(expression, entry.getValue(), o, context, throwPropertyExceptions);
}
Ognl.setRoot(context, oldRoot);
}
/**
* Sets the properties on the object using the default context, defaulting to not throwing
* exceptions for problems setting the properties.
*
* @param properties
* @param o
*/
public static void setProperties(Map properties, Object o) {
setProperties(properties, o, false);
}
/**
* Sets the properties on the object using the default context.
*
* @param properties the property map to set on the object
* @param o the object to set the properties into
* @param throwPropertyExceptions boolean which tells whether it should throw exceptions for
* problems setting the properties
*/
public static void setProperties(Map properties, Object o, boolean throwPropertyExceptions) {
Map context = Ognl.createDefaultContext(o);
setProperties(properties, o, context, throwPropertyExceptions);
}
/**
* Sets the named property to the supplied value on the Object, defaults to not throwing
* property exceptions.
*
* @param name the name of the property to be set
* @param value the value to set into the named property
* @param o the object upon which to set the property
* @param context the context which may include the TypeConverter
*/
public static void setProperty(String name, Object value, Object o, Map context) {
setProperty(name, value, o, context, false);
}
/**
* Sets the named property to the supplied value on the Object.
*
* @param name the name of the property to be set
* @param value the value to set into the named property
* @param o the object upon which to set the property
* @param context the context which may include the TypeConverter
* @param throwPropertyExceptions boolean which tells whether it should throw exceptions for
* problems setting the property
*/
public static void setProperty(String name, Object value, Object o, Map context, boolean throwPropertyExceptions) {
Ognl.setTypeConverter(context, XWorkConverter.getInstance());
Object oldRoot = Ognl.getRoot(context);
Ognl.setRoot(context, o);
internalSetProperty(name, value, o, context, throwPropertyExceptions);
Ognl.setRoot(context, oldRoot);
}
/**
* Looks for the real target with the specified property given a root Object which may be a
* CompoundRoot.
*
* @return the real target or null if no object can be found with the specified property
*/
public static Object getRealTarget(String property, Map context, Object root) throws OgnlException {
//special keyword, they must be cutting the stack
if ("top".equals(property)) {
return root;
}
if (root instanceof CompoundRoot) {
// find real target
CompoundRoot cr = (CompoundRoot) root;
try {
for (Iterator iterator = cr.iterator(); iterator.hasNext();) {
Object target = iterator.next();
if (
OgnlRuntime.hasSetProperty((OgnlContext) context, target, property)
||
OgnlRuntime.hasGetProperty((OgnlContext) context, target, property)
||
OgnlRuntime.getIndexedPropertyType((OgnlContext) context, target.getClass(), property) != OgnlRuntime.INDEXED_PROPERTY_NONE
) {
return target;
}
}
} catch (IntrospectionException ex) {
throw new OgnlException("Cannot figure out real target class", ex);
}
return null;
}
return root;
}
/**
* Wrapper around Ognl.setValue() to handle type conversion for collection elements.
* Ideally, this should be handled by OGNL directly.
*/
public static void setValue(String name, Map context, Object root, Object value) throws OgnlException {
Ognl.setValue(compile(name), context, root, value);
}
public static Object getValue(String name, Map context, Object root) throws OgnlException {
return Ognl.getValue(compile(name), context, root);
}
public static Object getValue(String name, Map context, Object root, Class resultType) throws OgnlException {
return Ognl.getValue(compile(name), context, root, resultType);
}
public static Object compile(String expression) throws OgnlException {
synchronized (expressions) {
Object o = expressions.get(expression);
if (o == null) {
o = Ognl.parseExpression(expression);
expressions.put(expression, o);
}
return o;
}
}
/**
* Copies the properties in the object "from" and sets them in the object "to"
* using specified type converter, or {@link com.opensymphony.xwork2.util.XWorkConverter} if none
* is specified.
*
* @param from the source object
* @param to the target object
* @param context the action context we're running under
* @param exclusions collection of method names to excluded from copying ( can be null)
* @param inclusions collection of method names to included copying (can be null)
* note if exclusions AND inclusions are supplied and not null nothing will get copied.
*/
public static void copy(Object from, Object to, Map context, Collection exclusions, Collection inclusions) {
if (from == null || to == null) {
log.warn("Attempting to copy from or to a null source. This is illegal and is bein skipped. This may be due to an error in an OGNL expression, action chaining, or some other event.");
return;
}
Map contextFrom = Ognl.createDefaultContext(from);
Ognl.setTypeConverter(contextFrom, XWorkConverter.getInstance());
Map contextTo = Ognl.createDefaultContext(to);
Ognl.setTypeConverter(contextTo, XWorkConverter.getInstance());
PropertyDescriptor[] fromPds;
PropertyDescriptor[] toPds;
try {
fromPds = getPropertyDescriptors(from);
toPds = getPropertyDescriptors(to);
} catch (IntrospectionException e) {
log.error("An error occured", e);
return;
}
Map toPdHash = new HashMap();
for (int i = 0; i < toPds.length; i++) {
PropertyDescriptor toPd = toPds[i];
toPdHash.put(toPd.getName(), toPd);
}
for (int i = 0; i < fromPds.length; i++) {
PropertyDescriptor fromPd = fromPds[i];
if (fromPd.getReadMethod() != null) {
boolean copy = true;
if (exclusions != null && exclusions.contains(fromPd.getName())) {
copy = false;
} else if (inclusions != null && !inclusions.contains(fromPd.getName())) {
copy = false;
}
if (copy == true) {
PropertyDescriptor toPd = (PropertyDescriptor) toPdHash.get(fromPd.getName());
if ((toPd != null) && (toPd.getWriteMethod() != null)) {
try {
Object expr = OgnlUtil.compile(fromPd.getName());
Object value = Ognl.getValue(expr, contextFrom, from);
Ognl.setValue(expr, contextTo, to, value);
} catch (OgnlException e) {
// ignore, this is OK
}
}
}
}
}
}
/**
* Copies the properties in the object "from" and sets them in the object "to"
* using specified type converter, or {@link com.opensymphony.xwork2.util.XWorkConverter} if none
* is specified.
*
* @param from the source object
* @param to the target object
* @param context the action context we're running under
*/
public static void copy(Object from, Object to, Map context) {
OgnlUtil.copy(from, to, context, null, null);
}
/**
* Get's the java beans property descriptors for the given source.
*
* @param source the source object.
* @return property descriptors.
* @throws IntrospectionException is thrown if an exception occurs during introspection.
*/
public static PropertyDescriptor[] getPropertyDescriptors(Object source) throws IntrospectionException {
BeanInfo beanInfo = getBeanInfo(source);
return beanInfo.getPropertyDescriptors();
}
/**
* Creates a Map with read properties for the given source object.
*
* If the source object does not have a read property (i.e. write-only) then
* the property is added to the map with the value here is no read method for property-name.
*
* @param source the source object.
* @return a Map with (key = read property name, value = value of read property).
* @throws IntrospectionException is thrown if an exception occurs during introspection.
* @throws OgnlException is thrown by OGNL if the property value could not be retrieved
*/
public static Map getBeanMap(Object source) throws IntrospectionException, OgnlException {
Map beanMap = new HashMap();
Map sourceMap = Ognl.createDefaultContext(source);
PropertyDescriptor[] propertyDescriptors = getPropertyDescriptors(source);
for (int i = 0; i < propertyDescriptors.length; i++) {
PropertyDescriptor propertyDescriptor = propertyDescriptors[i];
String propertyName = propertyDescriptor.getDisplayName();
Method readMethod = propertyDescriptor.getReadMethod();
if (readMethod != null) {
Object expr = OgnlUtil.compile(propertyName);
Object value = Ognl.getValue(expr, sourceMap, source);
beanMap.put(propertyName, value);
} else {
beanMap.put(propertyName, "There is no read method for " + propertyName);
}
}
return beanMap;
}
/**
* Get's the java bean info for the given source.
*
* @param from the source object.
* @return java bean info.
* @throws IntrospectionException is thrown if an exception occurs during introspection.
*/
public static BeanInfo getBeanInfo(Object from) throws IntrospectionException {
synchronized (beanInfoCache) {
BeanInfo beanInfo;
beanInfo = (BeanInfo) beanInfoCache.get(from.getClass());
if (beanInfo == null) {
beanInfo = Introspector.getBeanInfo(from.getClass(), Object.class);
beanInfoCache.put(from.getClass(), beanInfo);
}
return beanInfo;
}
}
static void internalSetProperty(String name, Object value, Object o, Map context, boolean throwPropertyExceptions) {
try {
setValue(name, context, o, value);
} catch (OgnlException e) {
Throwable reason = e.getReason();
String msg = "Caught OgnlException while setting property '" + name + "' on type '" + o.getClass().getName() + "'.";
Throwable exception = (reason == null) ? e : reason;
if (throwPropertyExceptions) {
throw new XWorkException(msg, exception);
} else {
log.warn(msg, exception);
}
}
}
}