WebJpaBatchMetadataProvider.java

/*
 * gvNIX is an open source tool for rapid application development (RAD).
 * Copyright (C) 2010 Generalitat Valenciana
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.gvnix.addon.web.mvc.addon.batch;

import java.util.HashMap;
import java.util.Map;

import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import org.gvnix.addon.jpa.addon.batch.JpaBatchMetadata;
import org.gvnix.addon.web.mvc.annotations.batch.GvNIXWebJpaBatch;
import org.osgi.service.component.ComponentContext;
import org.springframework.roo.addon.web.mvc.controller.addon.scaffold.WebScaffoldAnnotationValues;
import org.springframework.roo.classpath.PhysicalTypeIdentifier;
import org.springframework.roo.classpath.PhysicalTypeMetadata;
import org.springframework.roo.classpath.details.ClassOrInterfaceTypeDetails;
import org.springframework.roo.classpath.details.ItdTypeDetails;
import org.springframework.roo.classpath.itd.AbstractMemberDiscoveringItdMetadataProvider;
import org.springframework.roo.classpath.itd.ItdTypeDetailsProvidingMetadataItem;
import org.springframework.roo.model.JavaType;
import org.springframework.roo.project.LogicalPath;

/**
 * Provides {@link WebJpaBatchMetadata}. Prepares all required information to
 * construct a new instance of {@link WebJpaBatchMetadata}. Also register
 * metadata dependencies.
 * 
 * @author <a href="http://www.disid.com">DISID Corporation S.L.</a> made for <a
 *         href="http://www.dgti.gva.es">General Directorate for Information
 *         Technologies (DGTI)</a>
 * @since 1.1
 */
@Component
@Service
public final class WebJpaBatchMetadataProvider extends
        AbstractMemberDiscoveringItdMetadataProvider {

    private final Map<JavaType, String> entityToBatchMidMap = new HashMap<JavaType, String>();

    /**
     * The activate method for this OSGi component, this will be called by the
     * OSGi container upon bundle activation (result of the 'addon install'
     * command)
     * 
     * @param context the component context can be used to get access to the
     *        OSGi container (ie find out if certain bundles are active)
     */
    protected void activate(ComponentContext cContext) {
        context = cContext.getBundleContext();
        getMetadataDependencyRegistry().registerDependency(
                PhysicalTypeIdentifier.getMetadataIdentiferType(),
                getProvidesType());
        addMetadataTrigger(new JavaType(GvNIXWebJpaBatch.class.getName()));
    }

    /**
     * The deactivate method for this OSGi component, this will be called by the
     * OSGi container upon bundle deactivation (result of the 'addon uninstall'
     * command)
     * 
     * @param context the component context can be used to get access to the
     *        OSGi container (ie find out if certain bundles are active)
     */
    protected void deactivate(ComponentContext context) {
        getMetadataDependencyRegistry().deregisterDependency(
                PhysicalTypeIdentifier.getMetadataIdentiferType(),
                getProvidesType());
        removeMetadataTrigger(new JavaType(GvNIXWebJpaBatch.class.getName()));
    }

    /**
     * Return an instance of the Metadata offered by this add-on
     */
    protected ItdTypeDetailsProvidingMetadataItem getMetadata(
            String metadataIdentificationString, JavaType aspectName,
            PhysicalTypeMetadata governorPhysicalTypeMetadata,
            String itdFilename) {

        final WebJpaBatchAnnotationValues annotationValues = new WebJpaBatchAnnotationValues(
                governorPhysicalTypeMetadata);

        final JavaType service = annotationValues.getService();
        if (!annotationValues.isAnnotationFound() || service == null) {
            return null;
        }

        // get target service MID
        final String serviceMid = getTypeLocationService()
                .getPhysicalTypeIdentifier(service);
        if (serviceMid == null) {
            return null;
        }

        LogicalPath path = WebJpaBatchMetadata
                .getPath(metadataIdentificationString);

        WebScaffoldAnnotationValues webScaffoldMetadataValue = new WebScaffoldAnnotationValues(
                governorPhysicalTypeMetadata);

        String serviceMetadataKey = JpaBatchMetadata.createIdentifier(service,
                path);
        // register downstream dependency (service --> jpaBatch)
        getMetadataDependencyRegistry().registerDependency(serviceMetadataKey,
                metadataIdentificationString);

        JpaBatchMetadata serviceMetadata = (JpaBatchMetadata) getMetadataService()
                .get(serviceMetadataKey);

        if (serviceMetadata == null) {
            return null;
        }

        return new WebJpaBatchMetadata(metadataIdentificationString,
                aspectName, governorPhysicalTypeMetadata, annotationValues,
                serviceMetadata, webScaffoldMetadataValue);
    }

    /**
     * Define the unique ITD file name extension, here the resulting file name
     * will be **_ROO_GvNIXJpaBatch.aj
     */
    public String getItdUniquenessFilenameSuffix() {
        return "GvNIXWebJpaBatch";
    }

    protected String getGovernorPhysicalTypeIdentifier(
            String metadataIdentificationString) {
        JavaType javaType = WebJpaBatchMetadata
                .getJavaType(metadataIdentificationString);
        LogicalPath path = WebJpaBatchMetadata
                .getPath(metadataIdentificationString);
        return PhysicalTypeIdentifier.createIdentifier(javaType, path);
    }

    protected String createLocalIdentifier(JavaType javaType, LogicalPath path) {
        return WebJpaBatchMetadata.createIdentifier(javaType, path);
    }

    public String getProvidesType() {
        return WebJpaBatchMetadata.getMetadataIdentiferType();
    }

    @Override
    protected String getLocalMidToRequest(final ItdTypeDetails itdTypeDetails) {
        final JavaType governor = itdTypeDetails.getName();

        // If the governor is a form backing object, refresh its local metadata
        final String localMid = entityToBatchMidMap.get(governor);
        if (localMid != null) {
            return localMid;
        }

        // If the governor is a layer component that manages a form backing
        // object, refresh that object's local metadata
        return getRelatedEntityComponent(governor);
    }

    /**
     * If the given governor is a layer component (service, repository, etc.)
     * that manages an service for which we maintain web scaffold met-adata,
     * returns the ID of that meta-data, otherwise returns <code>null</code>.
     * <p/>
     * TODO doesn't handle the case where the governor is a component that
     * manages multiple entities, as it always returns the MID for the first
     * service found (in annotation order) for which we provide web meta-data.
     * We would need to enhance
     * {@link AbstractMemberDiscoveringItdMetadataProvider#getLocalMidToRequest}
     * to return a list of MIDs, rather than only one.
     * 
     * @param governor the governor to check (required)
     * @return see above
     */
    private String getRelatedEntityComponent(final JavaType governor) {
        final ClassOrInterfaceTypeDetails governorTypeDetails = getTypeLocationService()
                .getTypeDetails(governor);
        if (governorTypeDetails != null) {
            for (final JavaType type : governorTypeDetails.getLayerEntities()) {
                final String localMid = entityToBatchMidMap.get(type);
                if (localMid != null) {
                    // The ITD's governor is a layer component that manages an
                    // service for which we maintain web scaffold metadata =>
                    // refresh that MD in case a layer has appeared or gone
                    // away.
                    return localMid;
                }
            }
        }
        return null;
    }
}