org.apache.cayenne.commitlog.CommitLogModuleExtender Maven / Gradle / Ivy

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package org.apache.cayenne.commitlog;

import org.apache.cayenne.commitlog.meta.AnnotationCommitLogEntityFactory;
import org.apache.cayenne.commitlog.meta.CommitLogEntity;
import org.apache.cayenne.commitlog.meta.CommitLogEntityFactory;
import org.apache.cayenne.commitlog.meta.IncludeAllCommitLogEntityFactory;
import org.apache.cayenne.configuration.server.ServerModule;
import org.apache.cayenne.di.ListBuilder;
import org.apache.cayenne.di.Module;
import org.apache.cayenne.tx.TransactionFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collection;
import java.util.HashSet;

/**
 * A builder of a custom extensions module for {@link CommitLogModule} that customizes its services and installs
 * application-specific commit log listeners.
 *
 * @since 4.0
 */
public class CommitLogModuleExtender {

    private static final Logger LOGGER = LoggerFactory.getLogger(CommitLogModuleExtender.class);

    private Class entityFactoryType;
    private Collection> listenerTypes;
    private Collection listenerInstances;
    private boolean excludeFromTransaction;

    CommitLogModuleExtender() {
        entityFactory(IncludeAllCommitLogEntityFactory.class);
        this.listenerTypes = new HashSet<>();
        this.listenerInstances = new HashSet<>();
    }

    public CommitLogModuleExtender addListener(Class type) {
        this.listenerTypes.add(type);
        return this;
    }

    public CommitLogModuleExtender addListener(CommitLogListener instance) {
        this.listenerInstances.add(instance);
        return this;
    }

    /**
     * If called, events will be dispatched outside of the main commit
     * transaction. By default events are dispatched within the transaction, so
     * listeners can commit their code together with the main commit.
     */
    public CommitLogModuleExtender excludeFromTransaction() {
        this.excludeFromTransaction = true;
        return this;
    }

    /**
     * Installs entity filter that would only include entities annotated with
     * {@link CommitLog} on the callbacks. Also {@link CommitLog#confidential()}
     * properties will be obfuscated and {@link CommitLog#ignoredProperties()} -
     * excluded from the change collection.
     */
    public CommitLogModuleExtender commitLogAnnotationEntitiesOnly() {
        return entityFactory(AnnotationCommitLogEntityFactory.class);
    }

    /**
     * Installs a custom factory for {@link CommitLogEntity} objects that
     * allows implementors to use their own annotations, etc.
     */
    public CommitLogModuleExtender entityFactory(Class entityFactoryType) {
        this.entityFactoryType = entityFactoryType;
        return this;
    }

    /**
     * Creates a DI module that would install {@link CommitLogFilter} and its
     * listeners in Cayenne.
     */
    public Module module() {
        return binder -> {

            if (listenerTypes.isEmpty() && listenerInstances.isEmpty()) {
                LOGGER.info("No listeners configured. Skipping CommitLogFilter registration");
                return;
            }

            binder.bind(CommitLogEntityFactory.class).to(entityFactoryType);

            ListBuilder listeners = CommitLogModule.contributeListeners(binder)
                    .addAll(listenerInstances);

            // types have to be added one-by-one
            for (Class type : listenerTypes) {
                listeners.add(type);
            }

            if (excludeFromTransaction) {
                ServerModule.contributeDomainSyncFilters(binder).addAfter(CommitLogFilter.class, TransactionFilter.class);
            } else {
                ServerModule.contributeDomainSyncFilters(binder).insertBefore(CommitLogFilter.class, TransactionFilter.class);
            }
        };
    }
}