Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.cassandra.cql3; import java.util.Collections; import java.util.List; import org.apache.cassandra.audit.AuditLogContext; import org.apache.cassandra.cql3.functions.Function; import org.apache.cassandra.service.ClientState; import org.apache.cassandra.service.QueryState; import org.apache.cassandra.transport.messages.ResultMessage; public interface CQLStatement { /** * Returns all bind variables for the statement */ default List<ColumnSpecification> getBindVariables() { return Collections.emptyList(); } /** * Returns an array with the same length as the number of partition key columns for the table corresponding * to table. Each short in the array represents the bind index of the marker that holds the value for that * partition key column. If there are no bind markers for any of the partition key columns, null is returned. */ default short[] getPartitionKeyBindVariableIndexes() { return null; } /** * Return an Iterable over all of the functions (both native and user-defined) used by any component of the statement * * @return functions all functions found (may contain duplicates) */ default Iterable<Function> getFunctions() { return Collections.emptyList(); } /** * Perform any access verification necessary for the statement. * * @param state the current client state */ public void authorize(ClientState state); /** * Perform additional validation required by the statment. To be overriden by subclasses if needed. * * @param state the current client state */ public void validate(ClientState state); /** * Execute the statement and return the resulting result or null if there is no result. * * @param state the current query state * @param options options for this query (consistency, variables, pageSize, ...) * @param queryStartNanoTime the timestamp returned by System.nanoTime() when this statement was received */ public ResultMessage execute(QueryState state, QueryOptions options, long queryStartNanoTime); /** * Variant of execute used for internal query against the system tables, and thus only query the local node. * * @param state the current query state */ public ResultMessage executeLocally(QueryState state, QueryOptions options); /** * Provides the context needed for audit logging statements. */ AuditLogContext getAuditLogContext(); /** * Whether or not this CQL Statement has LWT conditions */ default public boolean hasConditions() { return false; } public static abstract class Raw { protected VariableSpecifications bindVariables; public void setBindVariables(List<ColumnIdentifier> variables) { bindVariables = new VariableSpecifications(variables); } public abstract CQLStatement prepare(ClientState state); } }