/*
* Copyright 1999-2005 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Contributors: Georg Lundesgaard
package org.apache.log4j.config;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.lang.reflect.*;
import java.util.*;
import org.apache.log4j.*;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.OptionHandler;
/**
General purpose Object property setter. Clients repeatedly invokes
{@link #setProperty setProperty(name,value)} in order to invoke setters
on the Object specified in the constructor. This class relies on the
JavaBeans {@link Introspector} to analyze the given Object Class using
reflection.
<p>Usage:
<pre>
PropertySetter ps = new PropertySetter(anObject);
ps.set("name", "Joe");
ps.set("age", "32");
ps.set("isMale", "true");
</pre>
will cause the invocations anObject.setName("Joe"), anObject.setAge(32),
and setMale(true) if such methods exist with those signatures.
Otherwise an {@link IntrospectionException} are thrown.
@author Anders Kristensen
@since 1.1
*/
public class PropertySetter {
protected Object obj;
protected PropertyDescriptor[] props;
/**
Create a new PropertySetter for the specified Object. This is done
in prepartion for invoking {@link #setProperty} one or more times.
@param obj the object for which to set properties
*/
public
PropertySetter(Object obj) {
this.obj = obj;
}
/**
Uses JavaBeans {@link Introspector} to computer setters of object to be
configured.
*/
protected
void introspect() {
try {
BeanInfo bi = Introspector.getBeanInfo(obj.getClass());
props = bi.getPropertyDescriptors();
} catch (IntrospectionException ex) {
LogLog.error("Failed to introspect "+obj+": " + ex.getMessage());
props = new PropertyDescriptor[0];
}
}
/**
Set the properties of an object passed as a parameter in one
go. The <code>properties</code> are parsed relative to a
<code>prefix</code>.
@param obj The object to configure.
@param properties A java.util.Properties containing keys and values.
@param prefix Only keys having the specified prefix will be set.
*/
public
static
void setProperties(Object obj, Properties properties, String prefix) {
new PropertySetter(obj).setProperties(properties, prefix);
}
/**
Set the properites for the object that match the
<code>prefix</code> passed as parameter.
*/
public
void setProperties(Properties properties, String prefix) {
int len = prefix.length();
for (Enumeration e = properties.propertyNames(); e.hasMoreElements(); ) {
String key = (String) e.nextElement();
// handle only properties that start with the desired frefix.
if (key.startsWith(prefix)) {
// ignore key if it contains dots after the prefix
if (key.indexOf('.', len + 1) > 0) {
//System.err.println("----------Ignoring---["+key
// +"], prefix=["+prefix+"].");
continue;
}
String value = OptionConverter.findAndSubst(key, properties);
key = key.substring(len);
if ("layout".equals(key) && obj instanceof Appender) {
continue;
}
setProperty(key, value);
}
}
activate();
}
/**
Set a property on this PropertySetter's Object. If successful, this
method will invoke a setter method on the underlying Object. The
setter is the one for the specified property name and the value is
determined partly from the setter argument type and partly from the
value specified in the call to this method.
<p>If the setter expects a String no conversion is necessary.
If it expects an int, then an attempt is made to convert 'value'
to an int using new Integer(value). If the setter expects a boolean,
the conversion is by new Boolean(value).
@param name name of the property
@param value String value of the property
*/
public
void setProperty(String name, String value) {
if (value == null) return;
name = Introspector.decapitalize(name);
PropertyDescriptor prop = getPropertyDescriptor(name);
//LogLog.debug("---------Key: "+name+", type="+prop.getPropertyType());
if (prop == null) {
LogLog.warn("No such property [" + name + "] in "+
obj.getClass().getName()+"." );
} else {
try {
setProperty(prop, name, value);
} catch (PropertySetterException ex) {
LogLog.warn("Failed to set property [" + name +
"] to value \"" + value + "\". ", ex.rootCause);
}
}
}
/**
Set the named property given a {@link PropertyDescriptor}.
@param prop A PropertyDescriptor describing the characteristics
of the property to set.
@param name The named of the property to set.
@param value The value of the property.
*/
public
void setProperty(PropertyDescriptor prop, String name, String value)
throws PropertySetterException {
Method setter = prop.getWriteMethod();
if (setter == null) {
throw new PropertySetterException("No setter for property ["+name+"].");
}
Class[] paramTypes = setter.getParameterTypes();
if (paramTypes.length != 1) {
throw new PropertySetterException("#params for setter != 1");
}
Object arg;
try {
arg = convertArg(value, paramTypes[0]);
} catch (Throwable t) {
throw new PropertySetterException("Conversion to type ["+paramTypes[0]+
"] failed. Reason: "+t);
}
if (arg == null) {
throw new PropertySetterException(
"Conversion to type ["+paramTypes[0]+"] failed.");
}
LogLog.debug("Setting property [" + name + "] to [" +arg+"].");
try {
setter.invoke(obj, new Object[] { arg });
} catch (Exception ex) {
throw new PropertySetterException(ex);
}
}
/**
Convert <code>val</code> a String parameter to an object of a
given type.
*/
protected
Object convertArg(String val, Class type) {
if(val == null)
return null;
String v = val.trim();
if (String.class.isAssignableFrom(type)) {
return val;
} else if (Integer.TYPE.isAssignableFrom(type)) {
return new Integer(v);
} else if (Long.TYPE.isAssignableFrom(type)) {
return new Long(v);
} else if (Boolean.TYPE.isAssignableFrom(type)) {
if ("true".equalsIgnoreCase(v)) {
return Boolean.TRUE;
} else if ("false".equalsIgnoreCase(v)) {
return Boolean.FALSE;
}
} else if (Priority.class.isAssignableFrom(type)) {
return OptionConverter.toLevel(v, (Level) Level.DEBUG);
}
return null;
}
protected
PropertyDescriptor getPropertyDescriptor(String name) {
if (props == null) introspect();
for (int i = 0; i < props.length; i++) {
if (name.equals(props[i].getName())) {
return props[i];
}
}
return null;
}
public
void activate() {
if (obj instanceof OptionHandler) {
((OptionHandler) obj).activateOptions();
}
}
}