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This module contains all API code for Apache Fluo. External dependencies should be limited. Any changes to public methods should be avoided. While the API module does not have compile time dependency on fluo-core, you must include fluo-core as a run-time dependency.
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/*
 * 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.fluo.api.client;

import java.util.Collection;
import java.util.Map;
import java.util.Set;

import org.apache.fluo.api.client.scanner.ScannerBuilder;
import org.apache.fluo.api.data.Bytes;
import org.apache.fluo.api.data.Column;
import org.apache.fluo.api.data.RowColumn;
import org.apache.fluo.api.data.Span;

/**
 * Allows users to read from a Fluo table at a certain point in time
 *
 * @since 1.0.0
 * @see AbstractSnapshotBase
 */
public interface SnapshotBase {

  /**
   * Retrieves the value (in {@link Bytes}) stored at a given row and {@link Column}. Returns null
   * if does not exist.
   */
  Bytes get(Bytes row, Column column);

  /**
   * Retrieves the value (in {@link Bytes}) stored at a given row and {@link Column}. Returns the
   * passed in defaultValue if does not exist.
   * 
   * @param defaultValue this will be returned if row+columns does not exists
   */
  Bytes get(Bytes row, Column column, Bytes defaultValue);

  /**
   * Given a row and set of {@link Column}s, retrieves a map that contains the values at those
   * {@link Column}s. Only columns that exist will be returned in map.
   */
  Map get(Bytes row, Set columns);

  /**
   * Given a row and list of {@link Column}s, retrieves a map that contains the values at those
   * {@link Column}s. Only columns that exist will be returned in map.
   */
  Map get(Bytes row, Column... columns);

  /**
   * Given a collection of rows and set of {@link Column}s, retrieves a map that contains the values
   * at those rows and {@link Column}s. Only rows and columns that exists will be returned in map.
   */
  Map> get(Collection rows, Set columns);

  /**
   * Given a collection of rows and list of {@link Column}s, retrieves a map that contains the
   * values at those rows and {@link Column}s. Only rows and columns that exists will be returned in
   * map.
   */
  Map> get(Collection rows, Column... columns);


  /**
   * Given a collection of {@link RowColumn}s, retrieves a map contains the values at
   * {@link RowColumn}. Only rows and columns that exists will be returned in map.
   */
  Map get(Collection rowColumns);

  /**
   * This method is the starting point for constructing a scanner. Scanners can be constructed over
   * a {@link Span} and/or with a subset of columns. Below is simple example of building a scanner.
   * 
   *    * 
   *   Transaction tx = ...;
   *   Span span = Span.exact("row4");
   *   Column col1 = new Column("fam1","qual1");
   *   Column col2 = new Column("fam1","qual2");
   * 
   *   //create a scanner over row4 fetching columns fam1:qual1 and fam1:qual2
   *   CellScanner cs = tx.scanner().over(span).fetch(col1,col2).build();
   *   for(RowColumnValue rcv : cs) {
   *     //do stuff with rcv
   *   }
   * 
   * 
   *
   * 
   * The following example shows how to build a row scanner.
   *
   * 
   * 
   *   RowScanner rs = tx.scanner().over(span).fetch(col1, col2).byRow().build();
   *   for (ColumnScanner colScanner : rs) {
   *     Bytes row = colScanner.getRow();
   *     for (ColumnValue cv : colScanner) {
   *       // do stuff with the columns and values in the row
   *     }
   *   }
   * 
   * 
   *
   * @return A scanner builder.
   */

  ScannerBuilder scanner();

  /**
   * Wrapper for {@link #get(Collection)} that uses Strings. All strings are encoded and decoded
   * using UTF-8.
   */
  Map gets(Collection rowColumns);

  /**
   * Wrapper for {@link #get(Collection, Set)} that uses Strings. All strings are encoded and
   * decoded using UTF-8.
   */
  Map> gets(Collection rows, Set columns);

  /**
   * Wrapper for {@link #get(Collection, Set)} that uses Strings. All strings are encoded and
   * decoded using UTF-8.
   */
  Map> gets(Collection rows, Column... columns);

  /**
   * Wrapper for {@link #get(Bytes, Column)} that uses Strings. All strings are encoded and decoded
   * using UTF-8.
   */
  String gets(CharSequence row, Column column);

  /**
   * Wrapper for {@link #get(Bytes, Column, Bytes)} that uses Strings. All strings are encoded and
   * decoded using UTF-8.
   */
  String gets(CharSequence row, Column column, String defaultValue);

  /**
   * Wrapper for {@link #get(Bytes, Set)} that uses Strings. All strings are encoded and decoded
   * using UTF-8.
   */
  Map gets(CharSequence row, Set columns);

  /**
   * Wrapper for {@link #get(Bytes, Set)} that uses Strings. All strings are encoded and decoded
   * using UTF-8.
   */
  Map gets(CharSequence row, Column... columns);

  /**
   * @return transactions start timestamp allocated from Oracle.
   */
  long getStartTimestamp();
}