TimerWrapper.java

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package com.sun.ejb.containers;

import java.util.Date;
import java.io.Serializable;

import javax.ejb.NoSuchObjectLocalException;
import javax.ejb.NoMoreTimeoutsException;
import javax.ejb.EJBException;
import javax.ejb.Timer;
import javax.ejb.TimerHandle;
import javax.ejb.ScheduleExpression;
import javax.ejb.FinderException;


import com.sun.enterprise.container.common.spi.util.IndirectlySerializable;
import com.sun.enterprise.container.common.spi.util.SerializableObjectFactory;
import org.glassfish.api.invocation.ComponentInvocation;

import com.sun.ejb.EjbInvocation;
import com.sun.ejb.ComponentContext;

/*
 * TimerWrapper is the application-level representation
 * of a timer.  Note that this class is not Serializable.
 * Timer instances are not intended to be directly persisted
 * by the application.  TimerHandle should be used instead.
 * 
 * @author Kenneth Saks
 */
public class TimerWrapper
    implements Timer, IndirectlySerializable {
    
    private TimerPrimaryKey timerId_;
    private EJBTimerService timerService_;

    TimerWrapper(TimerPrimaryKey timerId, EJBTimerService timerService) {
        timerId_      = timerId;
        timerService_ = timerService;   //TimerService passed in could be null
    }

    /*
     * Implementations of javax.ejb.Timer methods
     */
    public void cancel() 
        throws IllegalStateException, NoSuchObjectLocalException, EJBException {

        checkCallPermission();

        try {
            timerService_.cancelTimer(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        } catch(Exception e) {
            throw new EJBException(e);
        }

    }
    
    public long getTimeRemaining() 
        throws IllegalStateException, NoMoreTimeoutsException, NoSuchObjectLocalException {

        Date nextTimeout = getNextTimeout();

        Date now = new Date();
        long timeRemaining = nextTimeout.getTime() - now.getTime();

        return (timeRemaining > 0) ? timeRemaining : 0;
    }
    
    public Date getNextTimeout() 
        throws IllegalStateException, NoMoreTimeoutsException, NoSuchObjectLocalException {

        checkCallPermission();

        Date nextTimeout;

        try {
            nextTimeout = timerService_.getNextTimeout(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        } 

        if (nextTimeout == null) {
            throw new NoMoreTimeoutsException();
        }

        return nextTimeout;
    }
    
    public Serializable getInfo() 
        throws IllegalStateException, NoSuchObjectLocalException {

        checkCallPermission();

        Serializable info;

        try {
            info = timerService_.getInfo(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        } 

        return info;
    }
    
    public TimerHandle getHandle() 
        throws IllegalStateException, NoSuchObjectLocalException {

        checkCallPermission();

        if( !isPersistent() ) {
            throw new IllegalStateException("Only allowed for persistent timers");
        }

        if( !timerService_.timerExists(timerId_) ) {
            throw new NoSuchObjectLocalException("timer no longer exists");
        } 

        return new TimerHandleImpl(timerId_);
    }

    public ScheduleExpression getSchedule() throws java.lang.IllegalStateException, 
            javax.ejb.NoSuchObjectLocalException, javax.ejb.EJBException {

        checkCallPermission();
        ScheduleExpression schedule;

        if( !isCalendarTimer() ) {
            throw new IllegalStateException("Only allowed for calendar-based timers");
        }

        try {
            schedule = timerService_.getScheduleExpression(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        } 

        return schedule;
    }

    public boolean isCalendarTimer() throws java.lang.IllegalStateException,
            javax.ejb.NoSuchObjectLocalException, javax.ejb.EJBException {

        checkCallPermission();

        try {
            return timerService_.isCalendarTimer(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        }
    }


    public boolean isPersistent() throws java.lang.IllegalStateException, 
            javax.ejb.NoSuchObjectLocalException, javax.ejb.EJBException {

        checkCallPermission();
        try {
            return timerService_.isPersistent(timerId_);
        } catch(FinderException fe) {
            throw new NoSuchObjectLocalException("timer no longer exists", fe);
        } 
    }

    public boolean equals(Object o) {
        boolean equal = false;
        if(o instanceof TimerWrapper) {
            TimerWrapper other = (TimerWrapper) o;
            equal = other.timerId_.equals(this.timerId_);
        }
        return equal;
    }

    public int hashCode() {
        return timerId_.hashCode();
    }

    public String toString() {
        return "Timer " + timerId_;
    }

    /**
     * Verify that Timer method access is allowed from this context.
     * This method is static so that TimerHandle can call it even
     * before it has created a TimerWrapper instance.
     */
    private static void checkCallPermission() throws IllegalStateException {

        // Can't store a static ref because in embedded container it can be
        // changed by server restart
        EjbContainerUtil ejbContainerUtil = EjbContainerUtilImpl.getInstance();
        EJBTimerService timerService = EJBTimerService.getEJBTimerService();
        if( timerService == null ) {
            throw new IllegalStateException 
                ("EJBTimerService is not available");
        }

        ComponentInvocation inv = ejbContainerUtil.getCurrentInvocation();
        if (inv == null) {
            throw new IllegalStateException
                ("Invocation cannot be null");
        }
        ComponentInvocation.ComponentInvocationType invType = inv.getInvocationType();
        if( invType == ComponentInvocation.ComponentInvocationType.EJB_INVOCATION ) {
            if ( inv instanceof EjbInvocation ) {
                ComponentContext context = ((EjbInvocation) inv).context;
                // Delegate check to EJB context.  Let any
                // IllegalStateException bubble up.
                context.checkTimerServiceMethodAccess();
            }
        }
    }

    public SerializableObjectFactory getSerializableObjectFactory() {
        return new SerializedTimerWrapper(timerId_);
    }

    /**
     * Used by serialization code to serialize a TimerWrapper.  We
     * need a separate type that TimerHandle so that on deserialization
     * we know it started as a TimerWrapper instead of a TimerHandle.
     */
    public static class SerializedTimerWrapper
        implements SerializableObjectFactory
    {
        private TimerPrimaryKey timerId_;

        SerializedTimerWrapper() {}

        SerializedTimerWrapper(TimerPrimaryKey timerId) {
            timerId_ = timerId;
        }

        /**
         * When deserializing the timer wrapper create a TimerWrapper object.
         * Check if the record is valid only when making calls on the object.
         */
        public Object createObject() throws EJBException {
            // Can't store a static ref because in embedded container it can be 
            // changed by server restart
            EJBTimerService timerService = EJBTimerService.getEJBTimerService();
            TimerWrapper timer = new TimerWrapper(timerId_, timerService);

            return timer;
        }
    }

    private static class TimerHandleImpl implements TimerHandle {

        private TimerPrimaryKey timerId_;
        
        public TimerHandleImpl(TimerPrimaryKey timerId) {
            timerId_ = timerId;
        }

        /**
         * Materialize Timer from handle.  This must be coded
         * very defensively, since handle use might be attempted from 
         * outside of EJB container.  
         */
        public Timer getTimer() throws IllegalStateException, 
            NoSuchObjectLocalException, EJBException {
            TimerWrapper timer = null;

            // Can't store a static ref because in embedded container it can be 
            // changed by server restart
            EjbContainerUtil ejbContainerUtil = EjbContainerUtilImpl.getInstance();
            if( ejbContainerUtil != null ) {
                
                // Make sure use of timer service methods are allowed
                checkCallPermission();

                timer = getTimerInternal(timerId_);

            } else {
                throw new IllegalStateException
                    ("Attempt to use EJB timer from outside a container");
            }

            return timer;
        }

        private TimerWrapper getTimerInternal(TimerPrimaryKey timerId) 
            throws NoSuchObjectLocalException, EJBException {

            TimerWrapper timer = null;
            // Can't store a static ref because in embedded container it can be 
            // changed by server restart
            EJBTimerService timerService = EJBTimerService.getEJBTimerService();

            if( timerService != null ) {
                if( timerService.timerExists(timerId) ) {
                    timer = new TimerWrapper(timerId, timerService);
                } else {
                    throw new NoSuchObjectLocalException
                        ("timer is no longer active");
                }
            } else {
                throw new EJBException("EJB Timer Service not available");
            }
            
            return timer;
        }
    }
}