Java/Spring/IoC Injection

Dependant Check

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

///////////////////////////////////////////////////////////////////////////////////////
//File: depcheck.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="simpleBean1" class="SimpleBean" dependency-check="simple">
        <property name="someInt">
            <value>16</value>
        </property>
    </bean>  
    
    <bean id="simpleBean2" class="SimpleBean" dependency-check="objects">
        <property name="nestedSimpleBean">
            <ref local="nestedSimpleBean"/>
        </property>
    </bean>  
    
    <bean id="simpleBean3" class="SimpleBean" dependency-check="all">
        <property name="someInt">
            <value>16</value>
        </property>
    </bean>    
    
    <bean id="nestedSimpleBean" class="SimpleBean"/>
</beans>
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class SimpleBean {
    private int someInt;
    private SimpleBean nestedSimpleBean;
    public void setSomeInt(int someInt) {
        this.someInt = someInt;
    }
    public void setNestedSimpleBean(SimpleBean nestedSimpleBean) {
        this.nestedSimpleBean = nestedSimpleBean;
    }
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/depcheck.xml"));
        
        SimpleBean simpleBean1 = (SimpleBean)factory.getBean("simpleBean1");
        SimpleBean simpleBean2 = (SimpleBean)factory.getBean("simpleBean2");
        SimpleBean simpleBean3 = (SimpleBean)factory.getBean("simpleBean3");
    }
}

Hello World Xml With DI

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

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="provider" class="HelloWorldModel">
        <constructor-arg>
            <value>This is a configurable message</value>
        </constructor-arg>
    </bean>
    <bean id="renderer" class="StandardOutView">
        <property name="model">
            <ref local="provider"/>
        </property>
    </bean>
</beans>
///////////////////////////////////////////////////////////////////////////////////////
public interface Model {
  public String getMessage();
}

///////////////////////////////////////////////////////////////////////////////////////
public interface View {
    public void render();
    
    public void setModel(Model m);
    public Model getModel();
}

///////////////////////////////////////////////////////////////////////////////////////
public class StandardOutView implements View {
    private Model model = null;
    public void render() {
        if (model == null) {
            throw new RuntimeException(
                    "You must set the property model of class:"
                            + StandardOutView.class.getName());
        }
        System.out.println(model.getMessage());
    }
    public void setModel(Model m) {
        this.model = m;
    }
    public Model getModel() {
        return this.model;
    }
}
///////////////////////////////////////////////////////////////////////////////////////

public class HelloWorldModel implements Model {
    String mess;
    
    public HelloWorldModel(String m){
        mess = m;
    }
    
    public String getMessage() {
        return mess;
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class HelloWorldXmlWithDI {
    public static void main(String[] args) throws Exception {
        // get the bean factory
        BeanFactory factory = getBeanFactory();
        View mr = (View) factory.getBean("renderer");
        mr.render();
    }
    private static BeanFactory getBeanFactory() throws Exception {
        // get the bean factory
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/beans.xml"));
        return factory;
    }
}

Lookup Performance

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

///////////////////////////////////////////////////////////////////////////////////////
//File: lookup.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="helper" class="MyHelper" singleton="false"/>
    <bean id="abstractLookupBean" class="AbstractLookupDemoBean">
        <lookup-method name="getMyHelper" bean="helper"/>
    </bean>
    <bean id="standardLookupBean" class="StandardLookupDemoBean">
        <property name="myHelper">
            <ref local="helper"/>
        </property>
    </bean>
    <bean id="factoryLookupBean" class="BeanFactoryAwareLookupDemoBean"/>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
public interface DemoBean {
    public MyHelper getMyHelper();
    public void someOperation();
}

///////////////////////////////////////////////////////////////////////////////////////
public class MyHelper {
    public void doSomethingHelpful() {
        // do something!
    }
}
///////////////////////////////////////////////////////////////////////////////////////
public class StandardLookupDemoBean implements DemoBean {
    private MyHelper helper;
    
    public void setMyHelper(MyHelper helper) {
        this.helper = helper;
    }
    
    public MyHelper getMyHelper() {
        return this.helper;
    }
    
    public void someOperation() {
        helper.doSomethingHelpful();
    }
}
///////////////////////////////////////////////////////////////////////////////////////
public abstract class AbstractLookupDemoBean implements DemoBean {
    
    public abstract MyHelper getMyHelper();
    
    public void someOperation() {
        getMyHelper().doSomethingHelpful();
    }
}

///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
public class BeanFactoryAwareLookupDemoBean implements BeanFactoryAware,
        DemoBean {
    private BeanFactory factory = null;
    public void setBeanFactory(BeanFactory factory) throws BeansException {
        this.factory = factory;
    }
    public MyHelper getMyHelper() {
        return (MyHelper) factory.getBean("helper");
    }
    public void someOperation() {
        getMyHelper().doSomethingHelpful();
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.util.StopWatch;
public class LookupPerformance {
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/lookup.xml"));
        DemoBean abstractBean = (DemoBean) factory.getBean("abstractLookupBean");
        DemoBean factoryBean = (DemoBean) factory.getBean("factoryLookupBean");
        testPerf(abstractBean);
        testPerf(factoryBean);
    }
    public static void testPerf(DemoBean bean) {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("perfTest");
        for (int x = 0; x < 1000000; x++) {
            MyHelper helper = bean.getMyHelper();
            helper.doSomethingHelpful();
        }
        stopWatch.stop();
        System.out.println("1000000 gets took "
                + stopWatch.getTotalTimeSeconds() + " seconds");
    }
}

Model View Injection in Spring

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

///////////////////////////////////////////////////////////////////////////////////////
//File: beans.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="provider" class="HelloWorldModel">
        <constructor-arg>
            <value>This is a configurable message</value>
        </constructor-arg>
    </bean>
    <bean id="renderer" class="StandardOutView">
        <property name="model">
            <ref local="provider"/>
        </property>
    </bean>
</beans>
///////////////////////////////////////////////////////////////////////////////////////
public interface View {
    public void render();
    
    public void setModel(Model m);
    public Model getModel();
}

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

public interface Model {
  public String getMessage();
}
///////////////////////////////////////////////////////////////////////////////////////
public class StandardOutView implements View {
    private Model model = null;
    public void render() {
        if (model == null) {
            throw new RuntimeException(
                    "You must set the property model of class:"
                            + StandardOutView.class.getName());
        }
        System.out.println(model.getMessage());
    }
    public void setModel(Model m) {
        this.model = m;
    }
    public Model getModel() {
        return this.model;
    }
}
///////////////////////////////////////////////////////////////////////////////////////
public class HelloWorldModel implements Model {
    String mess;
    
    public HelloWorldModel(String m){
        mess = m;
    }
    
    public String getMessage() {
        return mess;
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class HelloWorldXml {
    public static void main(String[] args) throws Exception {
        // get the bean factory
        BeanFactory factory = getBeanFactory();
        View mr = (View) factory.getBean("renderer");
        Model mp = (Model) factory.getBean("provider");
        mr.setModel(mp);
        mr.render();
    }
    private static BeanFactory getBeanFactory() throws Exception {
        // get the bean factory
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/beans.xml"));
        return factory;
    }
}

Simple Inject By ID

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

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

//File: beans.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <!-- injecting built-in vals sample -->
    <bean id="injectSimple" class="InjectSimple">
        <property name="name">
            <value>John Smith</value>
        </property>
        <property name="age">
            <value>35</value>
        </property>
        <property name="height">
            <value>1.78</value>
        </property>
        <property name="isProgrammer">
            <value>true</value>
        </property>
        <property name="ageInSeconds">
            <value>1103760000</value>
        </property>
    </bean>
    
    <!-- oracle bean used for a few examples -->
    <bean id="oracle" name="wiseworm" class="BookwormOracle"/>
    
    <!-- injecting reference sample (using id) -->
    <bean id="injectRef" class="InjectRef">
        <property name="oracle">
            <ref local="oracle"/>
        </property>
    </bean>
    <!-- inject ref sample (using name) -->
    <!-- <bean id="injectRef" class="InjectRef">
        <property name="oracle">
            <ref bean="wiseworm"/>
        </property>
    </bean> -->
</beans>

///////////////////////////////////////////////////////////////////////////////////////
public interface Oracle {
    public String defineMeaningOfLife();
}

///////////////////////////////////////////////////////////////////////////////////////
public class InjectRef {
    private Oracle oracle;
    
    public void setOracle(Oracle oracle) {
        this.oracle = oracle;
        System.out.println(oracle.defineMeaningOfLife());
    }
}

///////////////////////////////////////////////////////////////////////////////////////
public class BookwormOracle implements Oracle {
    private Encyclopedia enc;
    public void setEncyclopedia(Encyclopedia enc) {
        this.enc = enc;
    }
    public String defineMeaningOfLife() {
        return "Encyclopedia"s are a waste of money - use the Internet";
    }
}
///////////////////////////////////////////////////////////////////////////////////////
public class Encyclopedia {
}

///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class InjectSimple {
    private String name;
    private int age;
    private float height;
    private boolean isProgrammer;
    private Long ageInSeconds;
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/beans.xml"));
        InjectSimple simple = (InjectSimple)factory.getBean("injectSimple");
        factory.getBean("injectRef");
        System.out.println(simple);
    }
    public void setAgeInSeconds(Long ageInSeconds) {
        this.ageInSeconds = ageInSeconds;
    }
    public void setIsProgrammer(boolean isProgrammer) {
        this.isProgrammer = isProgrammer;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public void setHeight(float height) {
        this.height = height;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String toString() {
        return    "Name :" + name + "\n"
                + "Age:" + age + "\n"
                + "Age in Seconds: " + ageInSeconds + "\n"
                + "Height: " + height + "\n"
                + "Is Programmer?: " + isProgrammer;
    }
}

Simple Inject By Name

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

///////////////////////////////////////////////////////////////////////////////////////
//File: beans.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <!-- injecting built-in vals sample -->
    <bean id="injectSimple" class="InjectSimple">
        <property name="name">
            <value>John Smith</value>
        </property>
        <property name="age">
            <value>35</value>
        </property>
        <property name="height">
            <value>1.78</value>
        </property>
        <property name="isProgrammer">
            <value>true</value>
        </property>
        <property name="ageInSeconds">
            <value>1103760000</value>
        </property>
    </bean>
    
    <!-- oracle bean used for a few examples -->
    <bean id="oracle" name="wiseworm" class="BookwormOracle"/>
    
    <!-- injecting reference sample (using id)
    <bean id="injectRef" class="InjectRef">
        <property name="oracle">
            <ref local="oracle"/>
        </property>
    </bean>
     -->
    <!-- inject ref sample (using name) -->
    <bean id="injectRef" class="InjectRef">
        <property name="oracle">
            <ref bean="wiseworm"/>
        </property>
    </bean>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
public interface Oracle {
    public String defineMeaningOfLife();
}

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

public class BookwormOracle implements Oracle {
    private Encyclopedia enc;
    public void setEncyclopedia(Encyclopedia enc) {
        this.enc = enc;
    }
    public String defineMeaningOfLife() {
        return "Encyclopedia"s are a waste of money - use the Internet";
    }
}

///////////////////////////////////////////////////////////////////////////////////////
public class Encyclopedia {
}

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

public class InjectRef {
    private Oracle oracle;
    
    public void setOracle(Oracle oracle) {
        this.oracle = oracle;
        System.out.println(oracle.defineMeaningOfLife());
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class InjectSimple {
    private String name;
    private int age;
    private float height;
    private boolean isProgrammer;
    private Long ageInSeconds;
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/beans.xml"));
        InjectSimple simple = (InjectSimple)factory.getBean("injectSimple");
        factory.getBean("injectRef");
        System.out.println(simple);
    }
    public void setAgeInSeconds(Long ageInSeconds) {
        this.ageInSeconds = ageInSeconds;
    }
    public void setIsProgrammer(boolean isProgrammer) {
        this.isProgrammer = isProgrammer;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public void setHeight(float height) {
        this.height = height;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String toString() {
        return    "Name :" + name + "\n"
                + "Age:" + age + "\n"
                + "Age in Seconds: " + ageInSeconds + "\n"
                + "Height: " + height + "\n"
                + "Is Programmer?: " + isProgrammer;
    }
}