content: /*
   * 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 com.datastax.oss.driver.api.core.cql;
  
  import com.datastax.oss.driver.api.core.session.Session;
  import com.datastax.oss.driver.internal.core.cql.DefaultPagingState;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import java.nio.ByteBuffer;
  
  /**
   * A safe wrapper around the paging state of a query.
   *
   * <p>This class performs additional checks to fail fast if the paging state is not reused on the
   * same query, and it provides utility methods for conversion to/from strings and byte arrays.
   *
   * <p>The serialized form returned by {@link #toBytes()} and {@link Object#toString()} is an opaque
   * sequence of bytes. Note however that it is <b>not cryptographically secure</b>: the contents are
   * not encrypted and the checks are performed with a simple MD5 checksum. If you need stronger
   * guarantees, you should build your own wrapper around {@link ExecutionInfo#getPagingState()}.
   */
  public interface PagingState {
  
    /** Parses an instance from a string previously generated with {@code toString()}. */
    @NonNull
    static PagingState fromString(@NonNull String string) {
      return DefaultPagingState.fromString(string);
    }
  
    /** Parses an instance from a byte array previously generated with {@link #toBytes()}. */
    @NonNull
    static PagingState fromBytes(byte[] bytes) {
      return DefaultPagingState.fromBytes(bytes);
    }
  
    /** Returns a representation of this object as a byte array. */
    byte[] toBytes();
  
    /**
     * Checks if this paging state can be safely reused for the given statement. Specifically, the
     * query string and any bound values must match.
     *
     * <p>Note that, if {@code statement} is a {@link SimpleStatement} with bound values, those values
     * must be encoded in order to perform the check. This method uses the default codec registry and
     * default protocol version. This might fail if you use custom codecs; in that case, use {@link
     * #matches(Statement, Session)} instead.
     *
     * <p>If {@code statement} is a {@link BoundStatement}, it is always safe to call this method.
     */
    default boolean matches(@NonNull Statement<?> statement) {
      return matches(statement, null);
    }
  
    /**
     * Alternative to {@link #matches(Statement)} that specifies the session the statement will be
     * executed with. <b>You only need this for simple statements, and if you use custom codecs.</b>
     * Bound statements already know which session they are attached to.
     */
    boolean matches(@NonNull Statement<?> statement, @Nullable Session session);
  
    /**
     * Returns the underlying "unsafe" paging state (the equivalent of {@link
     * ExecutionInfo#getPagingState()}).
     */
    @NonNull
    ByteBuffer getRawPagingState();
  }
  