PluggableTaskFlowProvider.java

/*
 * Copyright 2008-${YEAR} Zuse Institute Berlin (ZIB)
 *
 *  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 de.zib.gndms.infra.system;

import de.zib.gndms.logic.model.gorfx.taskflow.TaskFlowFactory;
import de.zib.gndms.logic.model.gorfx.taskflow.TaskFlowProviderImpl;
import de.zib.gndms.neomodel.common.Session;
import de.zib.gndms.stuff.GNDMSInjector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.ReflectionUtils;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;

/**
 * @author try ma ik jo rr a zib
 * @date 27.06.11  18:38
 * @brief
 */
public class PluggableTaskFlowProvider extends TaskFlowProviderImpl {

    protected final Logger logger = LoggerFactory.getLogger( this.getClass() );
    private String pluginDir;
    private boolean hasFactories = false;
    private GNDMSystem system;
    private ClassLoader cl;


    public void loadPlugins( boolean checkDeps ) {

        Map<String, TaskFlowFactory> plugins = new HashMap<String, TaskFlowFactory>( 10 );

        ServiceLoader<TaskFlowFactory> sl;
        if( getCl() != null )
            sl = ServiceLoader.load( TaskFlowFactory.class, getCl() );
        else
            sl = ServiceLoader.load( TaskFlowFactory.class );

        for( TaskFlowFactory bp : sl ) {
            try {
                register( bp, plugins );
            } catch ( IllegalStateException e ) {
                logger.warn( e.getMessage() );
            }
        }

        setFactories( plugins );

        if( checkDeps )
            checkDeps();

        // call all PostConstruct methods
        for( TaskFlowFactory bp : sl ) {
            for( Method method : bp.getClass().getDeclaredMethods() ) {
                if (method.getAnnotation( PostConstruct.class ) != null) {
                    ReflectionUtils.makeAccessible( method );
                    try {
                        method.invoke( bp, ( Object[] )null );
                    }
                    catch( IllegalAccessException e ) {
                        throw new RuntimeException( "THIS IS NOT HAPPENING!!! Method had been made accessible but is not accessible anyway", e );
                    }
                    catch( InvocationTargetException e ) {
                        throw new RuntimeException( "Could not call PostConstruct method (" + method.toGenericString() + ")", e );
                    }
                }
            }
        }

        // todo this is just for development change this for releases:
//        if ( getFactories().size() == 0 )
//            throw new IllegalStateException( "no plugs found" );
    }


    @PostConstruct
    public void loadPlugins( ) {

        PluginLoader pl = new PluginLoader( pluginDir );
        try {
            ClassLoader cl = pl.loadPlugins();
            setCl( cl );
            loadPlugins( true );
        } catch ( Exception e ) {
            throw new RuntimeException( e );
        }
    }


    @PreDestroy
    public void destroyPlugins( ) {
        
        final Map< String, TaskFlowFactory > factories = getFactories();
        
        for( TaskFlowFactory factory: factories.values() ) {
            for( Method method : factory.getClass().getDeclaredMethods() ) {
                if (method.getAnnotation( PreDestroy.class ) != null) {
                    ReflectionUtils.makeAccessible( method );
                    try {
                        method.invoke( factory, ( Object[] )null );
                    }
                    catch( IllegalAccessException e ) {
                        throw new RuntimeException( "THIS IS NOT HAPPENING!!! Method had been made accessible but is not accessible anyway", e );
                    }
                    catch( InvocationTargetException e ) {
                        throw new RuntimeException( "Could not call PreDestroy method (" + method.toGenericString() + ")", e );
                    }
                }
            }
        }
    }


    public int pluginCount( ) {
        return getFactories().size();
    }


    public void listPlugins( ) {
        Map<String, TaskFlowFactory> plugins = getFactories();
        for ( String k : plugins.keySet() ){
            logger.debug( k + ": " + plugins.get( k ).getVersion() + " class: " + plugins.get( k ).getClass().getName() );
        }
    }

    
    public void register( TaskFlowFactory tff, Map<String, TaskFlowFactory> plugins ) {

        if( plugins.containsKey( tff.getTaskFlowKey() ) )
            throw new IllegalStateException( "plugin " + tff.getTaskFlowKey() +" already exists" );
        
        logger.debug( "registering factory: " + tff.getTaskFlowKey() );
        plugins.put( tff.getTaskFlowKey(), tff );

        final GNDMSInjector injector =
                system.getInstanceDir().getSystemAccessInjector();
        injector.injectMembers( tff );
        tff.setInjector( injector );
        Session session = system.getDao().beginSession();
        try {
            tff.registerType( session );
            session.success();
        } finally {
            session.finish();
        }
    }


    public void checkDeps( ) {

        Map<String, TaskFlowFactory> plugins = getFactories();
        List<String> missing = new ArrayList<String>();

        for( String k : plugins.keySet() ) {
            TaskFlowFactory<?,?> tff = plugins.get( k );
            for( String dep : tff.depends( ) ) {
                if(! plugins.containsKey( dep ) )
                    missing.add( dep );
            }
        }


        if( missing.size() != 0 ) {
            StringBuilder mes = new StringBuilder();
            mes.append( "Missing plugin dependencies detected:" );
            for ( String k : missing ) {
                mes.append( '\n' );
                mes.append( k );
            }
            logger.warn( mes.toString() );
        }
    }


    @Override
    public void setFactories( Map<String, TaskFlowFactory> factories ) {

        if ( hasFactories )
            throw new IllegalStateException( "factories are already set"  );

        hasFactories = true;
        super.setFactories( factories );    // overriden method implementation
    }


    public GNDMSystem getSystem() {

        return system;
    }


    public void setSystem( final GNDMSystem system )  {

        this.system = system;
    }


    public ClassLoader getCl() {

        return cl;
    }


    public void setCl( final ClassLoader cl ) {

        this.cl = cl;
    }


    public String getPluginDir() {

        return pluginDir;
    }


    public void setPluginDir( final String pluginDir ) {

        this.pluginDir = pluginDir;
    }
}