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A driver for DataStax Enterprise (DSE)
and Apache Cassandra 1.2+ clusters that works exclusively with the
Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol,
supporting DSE-specific features such as geospatial types, DSE Graph and DSE authentication.
/*
* Copyright (C) 2012-2017 DataStax Inc.
*
* This software can be used solely with DataStax Enterprise. Please consult the license at
* http://www.datastax.com/terms/datastax-dse-driver-license-terms
*/
package com.datastax.driver.dse;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.exceptions.AuthenticationException;
import com.datastax.driver.core.exceptions.NoHostAvailableException;
import com.datastax.driver.core.exceptions.QueryExecutionException;
import com.datastax.driver.core.exceptions.QueryValidationException;
import com.datastax.driver.dse.graph.GraphOptions;
import com.datastax.driver.dse.graph.GraphResultSet;
import com.datastax.driver.dse.graph.GraphStatement;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.Map;
import java.util.concurrent.Future;
/**
* Holds connections to a DSE cluster, allowing it to be queried.
*
* This extends the CQL driver's {@link Session} with DSE-specific features.
*/
public interface DseSession extends Session {
/**
* Returns the {@link DseCluster} object this session is part of.
*
* @return the {@link DseCluster} object this session is part of.
*/
@Override
DseCluster getCluster();
/**
* Forces the initialization of this instance if it hasn't been
* initialized yet.
*
* Most users won't need to call this method explicitly. If you use {@link DseCluster#connect} to create your
* session, the returned object will be already initialized. Even if you create a non-initialized session through
* {@link DseCluster#newSession}, that session will get automatically initialized the first time it is used for
* querying. This method is thus only useful if you use {@link DseCluster#newSession} and want to explicitly force
* initialization without querying.
*
* Session initialization consists in connecting to the known Cassandra hosts (at least those that should not be
* ignored due to the {@code LoadBalancingPolicy} in place).
*
* If the {@link DseCluster} instance this session depends on is not itself initialized, it will be initialized by
* this method.
*
* If the session is already initialized, this method is a no-op.
*
* @return this object.
* @throws NoHostAvailableException if this initialization triggers the cluster initialization and no host amongst
* the contact points can be reached.
* @throws AuthenticationException if this initialization triggers the cluster initialization and an authentication
* error occurs while contacting the initial contact points.
*/
@Override
DseSession init();
/**
* {@inheritDoc}
*
* The {@link Session} object returned by the future's {@link Future#get() get} method can be safely cast
* to {@link DseSession}.
*
* @return a future that will complete when the session is fully initialized.
* @see #init()
*/
@Override
ListenableFuture initAsync();
/**
* {@inheritDoc}
*
* The keyspace name returned by this method is only relevant for CQL queries; for graph queries, the graph to
* target is determined by the graph name specified via {@link GraphStatement#setGraphName(String)}} or
* {@link GraphOptions#setGraphName(String)}.
*/
@Override
String getLoggedKeyspace();
/**
* Executes the provided graph query.
*
* This is a convenience method for {@code execute(new SimpleGraphStatement(query))}.
*
* @param query the graph query to execute.
* @return the result of the query. That result will never be null but can be empty (and will be for any query that
* returns no results).
* @throws NoHostAvailableException if no host in the cluster can be contacted successfully to execute this query.
*/
GraphResultSet executeGraph(String query);
/**
* Executes the provided graph query with the provided named parameters.
*
* This is a convenience method for {@code execute(new SimpleGraphStatement(query, values))}.
*
* @param query the graph query to execute.
* @param values the named parameters to send associated to the query. You can use Guava's
* {@link com.google.common.collect.ImmutableMap ImmutableMap} to build the map with a one-liner:
* {@code ImmutableMap.of("key1", value1, "key2", value2)}.
* @return the result of the query. That result will never be null but can be empty (and will be for any query that
* returns no results).
* @throws NoHostAvailableException if no host in the cluster can be contacted successfully to execute this query.
*/
GraphResultSet executeGraph(String query, Map values);
/**
* Executes the provided graph query.
*
* This method blocks until at least some result has been received from the
* database. However, for queries that return a result, it does not guarantee that the
* result has been received in full. But it does guarantee that some
* response has been received from the database, and in particular
* guarantees that if the request is invalid, an exception will be thrown
* by this method.
*
* @param statement the statement to execute.
* @return the result of the query. That result will never be null but can be empty (and will be for any query that
* returns no results).
* @throws NoHostAvailableException if no host in the cluster can be
* contacted successfully to execute this query.
* @throws QueryExecutionException if the query triggered an execution
* exception, i.e. an exception thrown by Cassandra when it cannot execute
* the query with the requested consistency level successfully.
* @throws QueryValidationException if the query if invalid (syntax error,
* unauthorized or any other validation problem).
*/
GraphResultSet executeGraph(GraphStatement statement);
/**
* Executes the provided graph query asynchronously.
*
* This method does not block. It returns as soon as the query has been
* passed to the underlying network stack. In particular, returning from
* this method does not guarantee that the query is valid or has even been
* submitted to a live node. Any exception pertaining to the failure of the
* query will be thrown when accessing the {@link ListenableFuture}.
*
* Note that for queries that don't return a result, you will need to
* access the Future's {@link java.util.concurrent.Future#get() get}
* method to make sure the query was successful.
*
* @param query the graph query to execute.
* @return a future on the result of the query.
*/
ListenableFuture executeGraphAsync(String query);
/**
* Executes the provided graph query asynchronously with the specified parameters.
*
* This method does not block. It returns as soon as the query has been
* passed to the underlying network stack. In particular, returning from
* this method does not guarantee that the query is valid or has even been
* submitted to a live node. Any exception pertaining to the failure of the
* query will be thrown when accessing the {@link ListenableFuture}.
*
* Note that for queries that don't return a result, you will need to
* access the Future's {@link java.util.concurrent.Future#get() get}
* method to make sure the query was successful.
*
* @param query the graph query to execute.
* @param values the named parameters to send associated to the query. You can use Guava's
* {@link com.google.common.collect.ImmutableMap ImmutableMap} to build the map with a one-liner:
* {@code ImmutableMap.of("key1", value1, "key2", value2)}.
* @return a future on the result of the query.
*/
ListenableFuture executeGraphAsync(String query, Map values);
/**
* Executes the provided Graph query asynchronously.
*
* This method does not block. It returns as soon as the query has been
* passed to the underlying network stack. In particular, returning from
* this method does not guarantee that the query is valid or has even been
* submitted to a live node. Any exception pertaining to the failure of the
* query will be thrown when accessing the {@link ListenableFuture}.
*
* Note that for queries that don't return a result, you will need to
* access the Future's {@link java.util.concurrent.Future#get() get}
* method to make sure the query was successful.
*
* @param statement the statement to execute.
* @return a future on the result of the query.
*/
ListenableFuture executeGraphAsync(GraphStatement statement);
}