com.flowlogix.ejb.StatefulUtil.java Source code

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Here is the source code for com.flowlogix.ejb.StatefulUtil.java

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/*
 * Copyright 2014 lprimak.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.flowlogix.ejb;

import com.google.common.base.Function;
import com.google.common.base.Predicates;
import com.google.common.collect.FluentIterable;
import java.util.List;
import java.util.regex.Pattern;
import javax.ejb.EJBException;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.session.Session;

/**
 * Stateful Session Bean (SFSB) Utilities
 * 
 * @author lprimak
 */
@Slf4j
public class StatefulUtil {
    /**
     * Pings all pingable SFSBs in the session
     * 
     * @param session 
     * @return true if successful, false if any of the pings failed
     */
    public static boolean pingStateful(Session session) {
        boolean rv = true;

        List<String> attrNames = FluentIterable.from(session.getAttributeKeys())
                .transform(new Function<Object, String>() {
                    @Override
                    public String apply(Object f) {
                        if (f instanceof String) {
                            return (String) f;
                        } else {
                            return null;
                        }
                    }
                }).filter(Predicates.and(Predicates.notNull(), Predicates.contains(ejbPattern))).toList();
        for (String attrName : attrNames) {
            synchronized (session.getId().toString().intern()) {
                try {
                    Object _pingable = session.getAttribute(attrName);
                    if (_pingable instanceof Pingable) {
                        Pingable pingable = (Pingable) _pingable;
                        pingable.ping();
                    }
                } catch (EJBException e) {
                    log.debug("Failed to Ping Stateful EJB: ", e);
                    rv = false; // signal failure if any of the pings fail
                    session.removeAttribute(attrName);
                }
            }
        }

        return rv;
    }

    /**
     * Retrieve Stateful EJB, Create if it doesn't exist
     * @param <T> EJB Type
     * @param session
     * @param cls Type of EJB
     * 
     * @return Stateful EJB
     */
    static public <T> T getStatefulEJB(Session session, Class<T> cls) {
        return getStatefulEJB(session, cls, true);
    }

    /**
     * Retrieve Stateful EJB, or null if its not available and not created
     * 
     * @param <T> Type of EJB
     * @param session
     * @param cls Class of EJB to be created / retrieved
     * @param doCreate Create EJB if does not exist
     * 
     * @return EJB, or null if doCreate is false and EJB does not exist
     */
    @SuppressWarnings("unchecked")
    static public <T> T getStatefulEJB(Session session, Class<T> cls, boolean doCreate) {
        final String attrName = StatefulUtil.ejbPrefix + cls.getName();
        T rv;
        synchronized (session.getId().toString().intern()) {
            rv = (T) session.getAttribute(attrName);
            if (doCreate && rv == null) {
                rv = new JNDIObjectLocator().getObject(cls);
                session.setAttribute(attrName, rv);
            }
        }
        return rv;
    }

    public static final String ejbPrefix = "ejb:";
    public static final Pattern ejbPattern = Pattern.compile(String.format("^%s.*", ejbPrefix));
}