/* ===================================================================
* ClassUtils.java
*
* Created Jul 15, 2008 8:20:38 AM
*
* This program 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 of
* the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
* ===================================================================
*/
package net.solarnetwork.node.util;
import java.beans.PropertyDescriptor;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Date;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.beans.PropertyBatchUpdateException;
/**
* Utility methods for dealing with classes at runtime.
*
* @author matt
* @version 1.2
*/
public final class ClassUtils {
private static final Set<String> DEFAULT_BEAN_PROP_NAME_IGNORE = new HashSet<String>(
Arrays.asList(new String[] { "class" }));
private static final Logger LOG = LoggerFactory.getLogger(ClassUtils.class);
/* Do not instantiate me. */
private ClassUtils() {
super();
}
/**
* Instantiate a class of a specific interface type.
*
* @param <T>
* the desired interface type
* @param className
* the class name that implements the interface
* @param type
* the desired interface
* @return new instance of the desired type
*/
public static <T> T instantiateClass(String className, Class<T> type) {
Class<? extends T> clazz = loadClass(className, type);
try {
T o = clazz.newInstance();
return o;
} catch ( Exception e ) {
throw new RuntimeException("Unable to instantiate class [" + className + ']', e);
}
}
/**
* Load a class of a particular type.
*
* <p>
* This uses the {@code type}'s ClassLoader to load the class. If that is
* not available, it will use the current thread's context class loader.
* </p>
*
* @param <T>
* the desired interface type
* @param className
* the class name that implements the interface
* @param type
* the desired interface
* @return the class
*/
public static <T> Class<? extends T> loadClass(String className, Class<T> type) {
try {
ClassLoader loader = type.getClassLoader();
if ( loader == null ) {
loader = Thread.currentThread().getContextClassLoader();
}
Class<?> clazz = loader.loadClass(className);
if ( !type.isAssignableFrom(clazz) ) {
throw new RuntimeException("Class [" + clazz + "] is not a [" + type + ']');
}
return clazz.asSubclass(type);
} catch ( ClassNotFoundException e ) {
throw new RuntimeException("Unable to load class [" + className + ']', e);
}
}
/**
* Set bean property values on an object from a Map.
*
* @param o
* the bean to set JavaBean properties on
* @param values
* a Map of JavaBean property names and their corresponding values to
* set
*/
public static void setBeanProperties(Object o, Map<String, ?> values) {
BeanWrapper bean = new BeanWrapperImpl(o);
bean.setPropertyValues(values);
}
/**
* Set bean property values on an object from a Map.
*
* @param o
* The bean to set JavaBean properties on.
* @param values
* A Map of JavaBean property names and their corresponding values to
* set.
* @param ignoreErrors
* Flag to ignore unknown and invalid properties.
* @since 1.2
*/
public static void setBeanProperties(Object o, Map<String, ?> values, boolean ignoreErrors) {
if ( o == null || values == null ) {
return;
}
BeanWrapper bean = PropertyAccessorFactory.forBeanPropertyAccess(o);
MutablePropertyValues pvs = new MutablePropertyValues(values);
try {
bean.setPropertyValues(pvs, ignoreErrors, ignoreErrors);
} catch ( PropertyBatchUpdateException e ) {
if ( ignoreErrors == false ) {
throw e;
}
}
}
/**
* Get a Map of non-null bean properties for an object.
*
* @param o
* the object to inspect
* @param ignore
* a set of property names to ignore (optional)
* @return Map (never null)
*/
public static Map<String, Object> getBeanProperties(Object o, Set<String> ignore) {
if ( ignore == null ) {
ignore = DEFAULT_BEAN_PROP_NAME_IGNORE;
}
Map<String, Object> result = new LinkedHashMap<String, Object>();
BeanWrapper bean = new BeanWrapperImpl(o);
PropertyDescriptor[] props = bean.getPropertyDescriptors();
for ( PropertyDescriptor prop : props ) {
if ( prop.getReadMethod() == null ) {
continue;
}
String propName = prop.getName();
if ( ignore != null && ignore.contains(propName) ) {
continue;
}
Object propValue = bean.getPropertyValue(propName);
if ( propValue == null ) {
continue;
}
result.put(propName, propValue);
}
return result;
}
/**
* Get a Map of non-null <em>simple</em> bean properties for an object.
*
* @param o
* the object to inspect
* @param ignore
* a set of property names to ignore (optional)
* @return Map (never <em>null</em>)
* @since 1.1
*/
public static Map<String, Object> getSimpleBeanProperties(Object o, Set<String> ignore) {
if ( ignore == null ) {
ignore = DEFAULT_BEAN_PROP_NAME_IGNORE;
}
Map<String, Object> result = new LinkedHashMap<String, Object>();
BeanWrapper bean = new BeanWrapperImpl(o);
PropertyDescriptor[] props = bean.getPropertyDescriptors();
for ( PropertyDescriptor prop : props ) {
if ( prop.getReadMethod() == null ) {
continue;
}
String propName = prop.getName();
if ( ignore != null && ignore.contains(propName) ) {
continue;
}
Class<?> propType = bean.getPropertyType(propName);
if ( !(propType.isPrimitive() || propType.isEnum() || String.class.isAssignableFrom(propType)
|| Number.class.isAssignableFrom(propType)
|| Character.class.isAssignableFrom(propType)
|| Byte.class.isAssignableFrom(propType)
|| Date.class.isAssignableFrom(propType)) ) {
continue;
}
Object propValue = bean.getPropertyValue(propName);
if ( propValue == null ) {
continue;
}
if ( propType.isEnum() ) {
propValue = propValue.toString();
} else if ( Date.class.isAssignableFrom(propType) ) {
propValue = ((Date) propValue).getTime();
}
result.put(propName, propValue);
}
return result;
}
/**
* Load a classpath SQL resource into a String.
*
* @param resourceName
* the SQL resource to load
* @param clazz
* the Class to load the resource from
* @return the String
*/
public static String getResourceAsString(String resourceName, Class<?> clazz) {
InputStream in = clazz.getResourceAsStream(resourceName);
if ( in == null ) {
throw new RuntimeException("Resource [" + resourceName + "] not found");
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
try {
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ( (bytesRead = in.read(buffer)) != -1 ) {
out.write(buffer, 0, bytesRead);
}
out.flush();
return out.toString();
} catch ( IOException e ) {
throw new RuntimeException("Error reading resource [" + resourceName + ']', e);
} finally {
try {
in.close();
} catch ( IOException ex ) {
LOG.warn("Could not close InputStream", ex);
}
try {
out.close();
} catch ( IOException ex ) {
LOG.warn("Could not close OutputStream", ex);
}
}
}
}