Inject java.util.Calendar instance

[oaktree]

How may I inject a java.util.Calendar instance into a bean? Also, how can I set the instance's time?

My naivety says I can create a java.util.Calendar instance using the following:

init-method="getInstance" abstract="true" scope="singleton"

But, that doesn't work.

Suggestions? Thanks.

[karldmoore]

This might be useful.
http://static.springframework.org/sp...ans-conversion

[Arthur Loder]

Hi oaktree,

The following should work:

<beans>

   <bean id="calendar" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
      <property name="staticMethod"><value>java.util.Calendar.getInstance</value></property>
   </bean>

</beans>

By default, the "singleton" property of the MethodInvokingFactoryBean is "true".

-Arthur Loder

[Jörg Heinicke]

How may I inject a java.util.Calendar instance into a bean? Also, how can I set the instance's time?

My naivety says I can create a java.util.Calendar instance using the following:

init-method="getInstance" abstract="true" scope="singleton"

But, that doesn't work.

abstract="true" prevents the bean declaration from creating the actual bean. You need a concrete bean declaration to get instances.

The @init-method is the wrong one. What you need is @factory-method.

Jörg

[Arthur Loder]

Hi oaktree,

Also, this might work for setting the date explicitly (using the Calendar.set(int, int, int) method):

<beans>

   <bean id="currentCalendar" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
      <property name="staticMethod"><value>java.util.Calendar.getInstance</value></property>
   </bean>

   <bean id="januaryFirst2006" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
      <property name="targetObject"><ref local="currentCalendar"/></property>
      <property name="targetMethod"><value>set</value></property>
      <property name="arguments">
         <list>
            <value>2006</value>
            <value>0</value>
            <value>1</value>
         </list>
      </property>
   </bean>

</beans>

I can't test this, so this may not work...

-Arthur Loder

[Arthur Loder]

Hi Oaktree,

I think the problem with my previous post is that the Calendar.set method does not return the Calendar object, so the configured Calendar is not returned from the FactoryBean.

Creating a specific FactoryBean implementation might be a good way to go:

CalendarFactoryBean.java:

package org.spring.forum;

import java.util.Calendar;

import org.springframework.beans.factory.config.AbstractFactoryBean;

public class CalendarFactoryBean extends AbstractFactoryBean  {

	/**
	 * Year; defaults to zero.
	 */
	private int year = 0;

	/**
	 * Month; defaults to zero.
	 */
	private int month = 0;

	/**
	 * Date; defaults to zero.
	 */
	private int date = 0;

	/**
	 * Number of hour of day (24 hour); defaults to zero.
	 */
	private int hourOfDay = 0;

	/**
	 * Number of minutes; defaults to zero.
	 */
	private int minute = 0;

	/**
	 * Number of seconds; defaults to zero.
	 */
	private int second = 0;

	public void setYear(int year) {
		this.year = year;
	}

	public void setMonth(int month) {
		this.month = month;
	}

	public void setDate(int date) {
		this.date = date;
	}

	public void setHourOfDay(int hourOfDay) {
		this.hourOfDay = hourOfDay;
	}

	public void setMinute(int minute) {
		this.minute = minute;
	}

	public void setSecond(int second) {
		this.second = second;
	}

	@Override
	protected Object createInstance() throws Exception {
		Calendar calendar = Calendar.getInstance();
		calendar.set(this.year, this.month, this.date, this.hourOfDay, this.minute, this.second);
		return calendar;
	}

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

}

Sample applicationContext.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">

<beans>

   <bean id="janFirst2006" class="org.spring.forum.CalendarFactoryBean">
      <property name="year" value="2006" />
      <property name="month" value="0" />
      <property name="date" value="1" />
   </bean>

   <bean id="janFirst2006_noon" class="org.spring.forum.CalendarFactoryBean">
      <property name="year" value="2006" />
      <property name="month" value="0" />
      <property name="date" value="1" />
      <property name="hourOfDay" value="12" />
   </bean>

</beans>

-Arthur Loder

[triley]

Here is another flavor of the same thing. The difference is you can add or set values of a calendar instance in case you needed "today". In my case I needed midnight tomorrow whenever my server starts.

public class CalendarFactoryBean extends AbstractFactoryBean {
    /**
     * Year; defaults to zero.
     */
    private String year;
    /**
     * Month; defaults to zero.
     */
    private String month;
    /**
     * Date; defaults to zero.
     */
    private String dayOfMonth;
    /**
     * Number of hour of day (24 hour); defaults to zero.
     */
    private String hourOfDay;
    /**
     * Number of minutes; defaults to zero.
     */
    private String minute;
    /**
     * Number of seconds; defaults to zero.
     */
    private String second;
    /**
     * Number of milliseconds
     */
    private String milliSecond;

    public void setYear(String year) {
        this.year = year;
    }

    public void setMonth(String month) {
        this.month = month;
    }

    public void setDayOfMonth(String dayOfMonth) {
        this.dayOfMonth = dayOfMonth;
    }

    public void setHourOfDay(String hourOfDay) {
        this.hourOfDay = hourOfDay;
    }

    public void setMinute(String minute) {
        this.minute = minute;
    }

    public void setSecond(String second) {
        this.second = second;
    }

    public void setMilliSecond(String milliSecond) {
        this.milliSecond = milliSecond;
    }    
    /**
     * Overrridden
     * @return
     * @throws Exception
     */
    @Override
    protected Object createInstance() throws Exception {
        Calendar calendar = Calendar.getInstance();
        setValue(calendar, Calendar.YEAR, year);
        setValue(calendar, Calendar.MONTH, month);
        setValue(calendar, Calendar.DAY_OF_MONTH, dayOfMonth);
        setValue(calendar, Calendar.HOUR_OF_DAY, hourOfDay);
        setValue(calendar, Calendar.MINUTE, minute);
        setValue(calendar, Calendar.SECOND, second);
        setValue(calendar, Calendar.MILLISECOND, second);        
        return calendar.getTimeInMillis();
    }

    public Class getObjectType() {
        return Calendar.class;
    }
    /**
     * Helper method to either add or set the value of the date
     * @param calendar The calendar instance
     * @param constant The calendar field to add of set the value
     * @param value The value
     */
    private void setValue(final Calendar calendar, final Integer constant, final String value) {
        if (calendar == null || constant == null) {
            throw new IllegalArgumentException("The calendar and the constant are required");
        }
        if (value != null) {
            if (value.contains("+") || value.contains("-")) {
                String amountValue = value.substring(1);
                Integer amount = Integer.parseInt(amountValue);
                calendar.add(constant, amount);
            } else {
                Integer amount = Integer.parseInt(value);
                calendar.set(constant, amount);
            }
        }
    }
}

My Context:

   <bean id="midnightTomorrow" class="com.example.CalendarFactoryBean">
      <property name="dayOfMonth" value="+1" />
      <property name="hourOfDay" value="0" />
      <property name="minute" value="0" />
      <property name="millisecond" value="0" />      
   </bean>

[Siluetti]

Hi all,

I know that this thread is as old as the hills, but in case somebody else will be searching a way to do this and hits this post, there is also a Spring way of doing this without any customizations:

    <bean id="yourPOJO" class="your.package.ClassName">
        <property name="calendar" ref="calendar" />
    </bean>

    <bean id="calendar" class="java.util.Calendar" factory-method="getInstance">
        <constructor-arg ref="timeZone" />
        <property name="timeInMillis" value="1352902760453" />
    </bean>

    <bean id="timeZone" class="java.util.TimeZone" factory-method="getTimeZone">
        <constructor-arg value="UTC" />
    </bean>

HTH, Jukka