event-bus/cassandra/src/main/java/org/apache/james/events/CassandraEventDeadLettersGroupDAO.java

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package org.apache.james.events;

import static com.datastax.driver.core.querybuilder.QueryBuilder.bindMarker;
import static org.apache.james.events.tables.CassandraEventDeadLettersGroupTable.GROUP;
import static org.apache.james.events.tables.CassandraEventDeadLettersGroupTable.TABLE_NAME;

import javax.inject.Inject;

import org.apache.james.backends.cassandra.utils.CassandraAsyncExecutor;

import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.querybuilder.QueryBuilder;
import com.github.fge.lambdas.Throwing;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

public class CassandraEventDeadLettersGroupDAO {
    private final CassandraAsyncExecutor executor;
    private final PreparedStatement insertStatement;
    private final PreparedStatement selectAllStatement;

    @Inject
    CassandraEventDeadLettersGroupDAO(Session session) {
        this.executor = new CassandraAsyncExecutor(session);
        this.insertStatement = prepareInsertStatement(session);
        this.selectAllStatement = prepareSelectStatement(session);
    }

    private PreparedStatement prepareInsertStatement(Session session) {
        return session.prepare(QueryBuilder.insertInto(TABLE_NAME)
            .value(GROUP, bindMarker(GROUP)));
    }

    private PreparedStatement prepareSelectStatement(Session session) {
        return session.prepare(QueryBuilder.select(GROUP)
            .from(TABLE_NAME));
    }

    Mono<Void> storeGroup(Group group) {
        return executor.executeVoid(insertStatement.bind()
                .setString(GROUP, group.asString()));
    }

    Flux<Group> retrieveAllGroups() {
        return executor.executeRows(selectAllStatement.bind())
            .map(Throwing.function(row -> Group.deserialize(row.getString(GROUP))));
    }
}