Java/Spring/IoC Factory Beans

Accessing Factory Beans

/*
Pro Spring
By Rob Harrop
Jan Machacek
ISBN: 1-59059-461-4
Publisher: Apress
*/
//spring.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="messageDigest" class="MessageDigestFactoryBean">
        <property name="algorithmName">
            <value>SHA1</value>
        </property>
    </bean>
</beans>
//////////////////////////////////////////////////////////////////////////////

import java.security.MessageDigest;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
public class MessageDigestFactoryBean implements FactoryBean, InitializingBean {
    private String algorithmName = "MD5";
    
    private MessageDigest messageDigest = null;
    public Object getObject() throws Exception {
       return messageDigest;
    }

    public Class getObjectType() {
       return MessageDigest.class;
    }

    public boolean isSingleton() {
       return true;
    }
    public void afterPropertiesSet() throws Exception {
        messageDigest = MessageDigest.getInstance(algorithmName);
    }
    
    public void setAlgorithmName(String algorithmName) {
        this.algorithmName = algorithmName;
    }
}

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

import java.security.MessageDigest;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class AccessingFactoryBeans {
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/spring.xml"));
        MessageDigest digest = (MessageDigest) factory
                .getBean("messageDigest");
       
        
        MessageDigestFactoryBean factoryBean = (MessageDigestFactoryBean) factory
                .getBean("&messageDigest");
    }
}

Custom Editor Example

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

///////////////////////////////////////////////////////////////////////////////////////
//File:custom.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean name="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
        <property name="customEditors">
            <map>
                <entry key="java.util.regex.Pattern">
                    <bean class="PatternPropertyEditor"/>
                </entry>
            </map>
        </property>
    </bean>
    <bean id="exampleBean" class="CustomEditorExample">
        <property name="searchPattern">
            <value>(dog|fox)</value>
        </property>
        <property name="textToSearch">
            <value>The quick brown fox jumped over the lazy dog.</value>
        </property>
    </bean>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
import java.beans.PropertyEditorSupport;
import java.util.regex.Pattern;
public class PatternPropertyEditor extends PropertyEditorSupport {
    public void setAsText(String text) throws IllegalArgumentException {
        Pattern pattern = Pattern.rupile(text);
        setValue(pattern);
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.CustomEditorConfigurer;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class CustomEditorExample {
    private Pattern searchPattern;
    private String textToSearch;
    public static void main(String[] args) {
        ConfigurableListableBeanFactory factory = new XmlBeanFactory(
                new FileSystemResource("build/custom.xml"));
        CustomEditorConfigurer config = (CustomEditorConfigurer) factory
                .getBean("customEditorConfigurer");
        config.postProcessBeanFactory(factory);
        CustomEditorExample bean = (CustomEditorExample) factory
                .getBean("exampleBean");
        System.out.println(bean.getMatchCount());
    }
    public void setSearchPattern(Pattern searchPattern) {
        this.searchPattern = searchPattern;
    }
    public void setTextToSearch(String textToSearch) {
        this.textToSearch = textToSearch;
    }
    public int getMatchCount() {
        Matcher m = searchPattern.matcher(textToSearch);
        int count = 0;
        while (m.find()) {
            count++;
        }
        return count;
    }
}

Hierarchical Bean Factory Usage

/*
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>
    <!-- hierarchical bean factories -->
    <bean id="target1" class="SimpleTarget">
        <property name="val">
            <ref bean="injectBeanParent"/>
        </property>
    </bean>
    
    <bean id="target2" class="SimpleTarget">
        <property name="val">
            <ref local="injectBean"/>
        </property>
    </bean>
    
    <bean id="target3" class="SimpleTarget">
        <property name="val">
            <ref parent="injectBean"/>
        </property>
    </bean>
    
    <bean id="injectBean" class="java.lang.String">
           <constructor-arg>
               <value>Bean In Child</value>
           </constructor-arg>
    </bean>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
//File: parent.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="injectBean" class="java.lang.String">
           <constructor-arg>
               <value>Bean In Parent</value>
           </constructor-arg>
    </bean>
    <bean id="injectBeanParent" class="java.lang.String">
           <constructor-arg>
               <value>Bean In Parent</value>
           </constructor-arg>
    </bean>
</beans>    

///////////////////////////////////////////////////////////////////////////////////////
public class SimpleTarget {
    private String val;
    
    public void setVal(String val) {
        this.val = val;
    }
    
    public String getVal() {
        return val;
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class HierarchicalBeanFactoryUsage {
    public static void main(String[] args) {
        BeanFactory parent = new XmlBeanFactory(new FileSystemResource(
                "build/parent.xml"));
        BeanFactory child = new XmlBeanFactory(new FileSystemResource(
                "build/beans.xml"), parent);
        SimpleTarget target1 = (SimpleTarget) child.getBean("target1");
        SimpleTarget target2 = (SimpleTarget) child.getBean("target2");
        SimpleTarget target3 = (SimpleTarget) child.getBean("target3");
        System.out.println(target1.getVal());
        System.out.println(target2.getVal());
        System.out.println(target3.getVal());
    }
}

Logging Bean Example

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

///////////////////////////////////////////////////////////////////////////////////////
//File: logging.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="loggingBean" class="LoggingBean"/>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
import org.apache.rumons.logging.Log;
import org.apache.rumons.logging.LogFactory;
import org.springframework.beans.factory.BeanNameAware;
public class LoggingBean implements BeanNameAware {
    private static final Log log = LogFactory.getLog(LoggingBean.class);
    
    private String beanName = null;
    public void setBeanName(String beanName) {
        this.beanName = beanName;
    }
    
    public void someOperation() {
        if(log.isInfoEnabled()) {
            log.info("Bean [" + beanName + "] - someOperation()");
        }
    }
}

///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class LoggingBeanExample {
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/logging.xml"));
        
        LoggingBean bean = (LoggingBean)factory.getBean("loggingBean");
        bean.someOperation();
    }
}

Message Digest Example

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

///////////////////////////////////////////////////////////////////////////////////////
//File: factory.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="shaDigest" class="MessageDigestFactoryBean">
        <property name="algorithmName">
            <value>SHA1</value>
        </property>
    </bean>
    <bean id="defaultDigest" class="MessageDigestFactoryBean"/>
    <bean id="digester" class="MessageDigester">
        <property name="digest1">
            <ref local="shaDigest"/>
        </property>
        <property name="digest2">
            <ref local="defaultDigest"/>
        </property>
    </bean>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
import java.security.MessageDigest;
import sun.misc.BASE64Encoder;
public class MessageDigester {
    private MessageDigest digest1 = null;
    private MessageDigest digest2 = null;
    
    public void setDigest1(MessageDigest digest1) {
        this.digest1 = digest1;
    }
    
    public void setDigest2(MessageDigest digest2) {
        this.digest2 = digest2;
    }
    
    public void digest(String msg) {
        System.out.println("Using digest1");
        digest(msg, digest1);
        System.out.println("Using digest2");
        digest(msg, digest2);
    }
    
    private void digest(String msg, MessageDigest digest) {
        System.out.println("Using alogrithm: " + digest.getAlgorithm());
        digest.reset();
        byte[] bytes = msg.getBytes();
        byte[] out = digest.digest(bytes);
        BASE64Encoder enc = new BASE64Encoder();
        System.out.println(enc.encode(out));
    }
}

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

import java.security.MessageDigest;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
public class MessageDigestFactoryBean implements FactoryBean, InitializingBean {
    private String algorithmName = "MD5";
    
    private MessageDigest messageDigest = null;
    public Object getObject() throws Exception {
       return messageDigest;
    }

    public Class getObjectType() {
       return MessageDigest.class;
    }

    public boolean isSingleton() {
       return true;
    }
    public void afterPropertiesSet() throws Exception {
        messageDigest = MessageDigest.getInstance(algorithmName);
    }
    
    public void setAlgorithmName(String algorithmName) {
        this.algorithmName = algorithmName;
    }
}

///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class MessageDigestExample {
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/factory.xml"));
        MessageDigester digester = (MessageDigester) factory
                .getBean("digester");
        digester.digest("Hello World!");
    }
}

Method Replacement Example

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

///////////////////////////////////////////////////////////////////////////////////////
//File: replacement.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="methodReplacer" class="FormatMessageReplacer"/>
    <bean id="replacementTarget" class="ReplacementTarget">
        <replaced-method name="formatMessage" replacer="methodReplacer">
            <arg-type>String</arg-type>
        </replaced-method>
    </bean>
    <bean id="standardTarget" class="ReplacementTarget"/>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
public class ReplacementTarget {
    public String formatMessage(String msg) {
        return "<h1>" + msg + "</h1>";
    }
    
    public String formatMessage(Object msg) {
        return "<h1>" + msg + "</h1>";
    }
    
    public void foo() {
        
    }
}
///////////////////////////////////////////////////////////////////////////////////////
import java.lang.reflect.Method;
import org.springframework.beans.factory.support.MethodReplacer;
public class FormatMessageReplacer implements MethodReplacer {
    public Object reimplement(Object target, Method method, Object[] args)
            throws Throwable {
        if (isFormatMessageMethod(method)) {
            String msg = (String) args[0];
            return "<h2>" + msg + "</h2>";
        } else {
            throw new IllegalArgumentException("Unable to reimplement method "
                    + method.getName());
        }
    }
    private boolean isFormatMessageMethod(Method method) {
        // check correct number of params
        if (method.getParameterTypes().length != 1) {
            return false;
        }
        // check method name
        if (!("formatMessage".equals(method.getName()))) {
            return false;
        }
        // check return type
        if (method.getReturnType() != String.class) {
            return false;
        }
        // check parameter type is correct
        if (method.getParameterTypes()[0] != String.class) {
            return false;
        }
        return true;
    }
}

///////////////////////////////////////////////////////////////////////////////////////
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 MethodReplacementExample {
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/replacement.xml"));
        ReplacementTarget replacementTarget = (ReplacementTarget) factory
                .getBean("replacementTarget");
        ReplacementTarget standardTarget = (ReplacementTarget) factory
                .getBean("standardTarget");
        displayInfo(replacementTarget);
        displayInfo(standardTarget);
    }
    private static void displayInfo(ReplacementTarget target) {
        System.out.println(target.formatMessage("Hello World!"));
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("perfTest");
        for (int x = 0; x < 1000000; x++) {
            String out = target.formatMessage("foo");
        }
        stopWatch.stop();
        System.out.println("1000000 invocations took: "
                + stopWatch.getTotalTimeMillis() + " ms");
    }
}

Property Editor Bean

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

///////////////////////////////////////////////////////////////////////////////////////
//File: builtin.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <bean id="builtInSample" class="PropertyEditorBean">
        <property name="class">
            <value>java.lang.String</value>
        </property>
        <property name="file">
            <value>c:/test.txt</value>
        </property>
        <property name="locale">
            <value> en-GB </value>
        </property>
        <property name="url">
            <value>http://www.springframework.org</value>
        </property>
        <property name="properties">
            <value> 
                name=foo 
                age=19 
            </value>
        </property>
        <property name="strings">
            <value>rob,jan,rod,jurgen,alef</value>
        </property>
        <property name="bytes">
            <value>Hello World</value>
        </property>
    </bean>
</beans>

///////////////////////////////////////////////////////////////////////////////////////
import java.io.File;
import java.net.URL;
import java.util.Locale;
import java.util.Properties;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
public class PropertyEditorBean {
    private Class cls;
    private File file;
    private URL url;
    private Locale locale;
    private Properties properties;
    private String[] strings;
    private byte[] bytes;
    public void setClass(Class cls) {
        System.out.println("Setting class: " + cls.getName());
        this.cls = cls;
    }
    public void setFile(File file) {
        System.out.println("Setting file: " + file.getName());
        this.file = file;
    }
    public void setLocale(Locale locale) {
        System.out.println("Setting locale: " + locale.getDisplayName());
        this.locale = locale;
    }
    public void setProperties(Properties properties) {
        System.out.println("Loaded " + properties.size() + " properties");
        this.properties = properties;
    }
    public void setStrings(String[] strings) {
        System.out.println("Loaded " + strings.length + " Strings");
        this.strings = strings;
    }
    public void setUrl(URL url) {
        System.out.println("Setting URL: " + url.toExternalForm());
        this.url = url;
    }
    public void setBytes(byte[] bytes) {
        System.out.println("Adding " + bytes.length + " bytes");
        this.bytes = bytes;
    }
    public static void main(String[] args) {
        BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
                "build/builtin.xml"));
        PropertyEditorBean bean = (PropertyEditorBean) factory
                .getBean("builtInSample");
    }
}