java code for Lazy Init

/*
Pro Spring
By Rob Harrop
Jan Machacek
ISBN: 1-59059-461-4
Publisher: Apress
*/


///////////////////////////////////////////////////////////////////////////////////////
//File: lazy.xml




c:/test.txt







///////////////////////////////////////////////////////////////////////////////////////
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;

public class DestructiveBeanWithInterface implements InitializingBean,
DisposableBean {

private InputStream is = null;

public String filePath = null;

public void afterPropertiesSet() throws Exception {

System.out.println("Initializing Bean");

if (filePath == null) {
throw new IllegalArgumentException(
"You must specify the filePath property of " + DestructiveBean.class);
}

is = new FileInputStream(filePath);
}

public void destroy() {

System.out.println("Destroying Bean");

if (is != null) {
try {
is.close();
is = null;
} catch (IOException ex) {
System.err.println("WARN: An IOException occured"
+ " trying to close the InputStream");
}
}
}

public void setFilePath(String filePath) {
this.filePath = filePath;
}
}


///////////////////////////////////////////////////////////////////////////////////////

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

public class ShutdownHookBean implements BeanFactoryAware,
Runnable {

private ConfigurableListableBeanFactory factory;

public void setBeanFactory(BeanFactory factory) throws BeansException {

if (factory instanceof ConfigurableListableBeanFactory) {
this.factory = (ConfigurableListableBeanFactory) factory;
Runtime.getRuntime().addShutdownHook(new Thread(this));
}
}

public void run() {
if (factory != null) {
System.out.println("Destroying Singletons");
factory.destroySingletons();
System.out.println("Singletons Destroyed");
}
}

}

///////////////////////////////////////////////////////////////////////////////////////

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;

public class DestructiveBean implements InitializingBean {

private InputStream is = null;

public String filePath = null;

public void afterPropertiesSet() throws Exception {

System.out.println("Initializing Bean");

if (filePath == null) {
throw new IllegalArgumentException(
"You must specify the filePath property of " + DestructiveBean.class);
}

is = new FileInputStream(filePath);
}

public void destroy() {

System.out.println("Destroying Bean");

if (is != null) {
try {
is.close();
is = null;
} catch (IOException ex) {
System.err.println("WARN: An IOException occured"
+ " trying to close the InputStream");
}
}
}

public void setFilePath(String filePath) {
this.filePath = filePath;
}
}

///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

public class LazyInitDemo {

public static void main(String[] args) {
ApplicationContext ctx = new FileSystemXmlApplicationContext(
"build/lazy.xml");

DestructiveBeanWithInterface bean = (DestructiveBeanWithInterface) ctx
.getBean("destructiveBean");
}
}