Hibernate3Plugin.java

/*
 * Copyright 2016 the original author or authors.
 *
 * 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 org.hotswap.agent.plugin.hibernate3.session;

import org.hotswap.agent.annotation.FileEvent;
import org.hotswap.agent.annotation.Init;
import org.hotswap.agent.annotation.LoadEvent;
import org.hotswap.agent.annotation.Maven;
import org.hotswap.agent.annotation.OnClassFileEvent;
import org.hotswap.agent.annotation.OnClassLoadEvent;
import org.hotswap.agent.annotation.OnResourceFileEvent;
import org.hotswap.agent.annotation.Plugin;
import org.hotswap.agent.annotation.Versions;
import org.hotswap.agent.command.Command;
import org.hotswap.agent.command.ReflectionCommand;
import org.hotswap.agent.command.Scheduler;
import org.hotswap.agent.javassist.CtClass;
import org.hotswap.agent.logging.AgentLogger;
import org.hotswap.agent.util.AnnotationHelper;

/**
 * Reload Hibernate configuration after entity create/change.
 *
 * @author Jiri Bubnik
 * @author alpapad@gmail.com
 */
@Plugin(name = "Hibernate3", //
        group = "groupHibernate",
        description = "Reload Hibernate configuration after entity create/change.", //
        testedVersions = { "3.6" }, //
        expectedVersions = { "3.6" }, //
        supportClass = { Hibernate3Transformers.class })
@Versions(maven = { @Maven(value = "[3.0,4.0)", artifactId = "hibernate-core", groupId = "org.hibernate") })
public class Hibernate3Plugin {

    /** The Constant ENTITY_ANNOTATION. */
    private static final String ENTITY_ANNOTATION = "javax.persistence.Entity";

    /** The logger. */
    private static AgentLogger LOGGER = AgentLogger.getLogger(Hibernate3Plugin.class);

    /** The scheduler. */
    @Init
    Scheduler scheduler;

    /** The app class loader. */
    @Init
    ClassLoader appClassLoader;

    /** The version. */
    String version;

    /** The reload session factory command. */
    // refresh command
    private final Command reloadSessionFactoryCommand = new ReflectionCommand(this, Hibernate3RefreshCommand.class.getName(), "reloadSessionFactory");

    /**
     * Plugin initialization properties (from Hibernate3JPAHelper or
     * SessionFactoryProxy).
     */
    @Init
    public void init() {
        LOGGER.info("Hibernate3 Session plugin initialized", version);
    }

    /** The enabled. */
    boolean enabled = true;

    /**
     * Disable plugin (if environment is JPA)
     *
     * Need to re-think this: Maybe use OverrideConfig to hold this info?.
     */
    public void disable() {
        LOGGER.info("Disabling Hibernate3 Session plugin since JPA is active");
        this.enabled = false;
    }

    /**
     * Sets the version.
     *
     * @param v
     *            the new version
     */
    public void setVersion(String v) {
        this.version = v;
        LOGGER.info("Hibernate Core version '{}'", version);
    }

    /**
     * Reload after entity class change. It covers also @Entity annotation
     * removal.
     *
     * @param clazz
     *            the clazz
     * @param original
     *            the original
     */
    @OnClassLoadEvent(classNameRegexp = ".*", events = LoadEvent.REDEFINE)
    public void entityReload(CtClass clazz, Class<?> original) {
        // TODO list of entity/resource files is known to hibernate,
        // better to check this list
        if (AnnotationHelper.hasAnnotation(original, ENTITY_ANNOTATION) || AnnotationHelper.hasAnnotation(clazz, ENTITY_ANNOTATION)) {
            LOGGER.debug("Entity reload class {}, original classloader {}", clazz.getName(), original.getClassLoader());
            refresh(500);
        }
    }

    /**
     * New entity class - not covered by reloading mechanism.
     * <p/>
     * Increase the reload timeout to avoid duplicate reloading in case of
     * recompile with IDE and delete/create event sequence - than create is
     * cached by this event and hotswap for the same class by entityReload.
     *
     * @param clazz
     *            the clazz
     * @throws Exception
     *             the exception
     */
    @OnClassFileEvent(classNameRegexp = ".*", events = { FileEvent.CREATE })
    public void newEntity(CtClass clazz) throws Exception {
        if (AnnotationHelper.hasAnnotation(clazz, ENTITY_ANNOTATION)) {
            refresh(500);
        }
    }

    /**
     * Reload on hbm file modifications.
     */
    @OnResourceFileEvent(path = "/", filter = ".*.hbm.xml")
    public void refreshOnHbm() {
        refresh(500);
    }

    /**
     * Reload on hibernate.cfg.xml file modifications
     */
    @OnResourceFileEvent(path = "/", filter = ".*.cfg.xml")
    public void refreshOnCfg() {
        refresh(500);
    }

    // reload the configuration - schedule a command to run in the application
    /**
     * Refresh.
     *
     * @param timeout
     *            the timeout
     */
    // classloader and merge duplicate commands.
    public void refresh(int timeout) {
        if (enabled) {
            scheduler.scheduleCommand(reloadSessionFactoryCommand, timeout);
        }
    }

}