flink-core-1.7.0-sources.jar!/org/apache/flink/api/common/state/MapStateDescriptor.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/internal/InternalKvState.java

这里利用builder创建StateTtlConfig，之后通过StateDescriptor的enableTimeToLive方法传递该config

flink-core-1.7.0-sources.jar!/org/apache/flink/api/common/functions/RuntimeContext.java

flink-core-1.7.0-sources.jar!/org/apache/flink/api/common/state/State.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/functions/timestamps/BoundedOutOfOrdernessTimestampExtractor.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/functions/timestamps/AscendingTimestampExtractor.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/functions/source/SourceFunction.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/TimeCharacteristic.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/CheckpointStreamFactory.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/CheckpointStorage.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/StateBackend.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/CheckpointStreamFactory.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/CheckpointStorage.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/DefaultOperatorStateBackend.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/OperatorStateBackend.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/StateBackend.java

使用StreamExecutionEnvironment.enableCheckpointing方法来设置开启checkpoint；具体可以使用enableCheckpointing(long interval)，或者enableCheckpointing(long interval, CheckpointingMode mode)；interval用于指定checkpoint的触发间隔(单位milliseconds)，而CheckpointingMode默认是CheckpointingMode.EXACTLY_ON...

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/taskmanager/Task.java

flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/checkpoint/CheckpointCoordinatorDeActivator.java

CounterSource是一个有状态的RichParallelSourceFunction，它实现了ListCheckpointed接口，snapshotState方法返回了当前的offset，而restoreState方法则根据传入的state来恢复本地的offset；这里要注意，如果要在failure或者recovery的时候达到exactly-once的语义，这里更新offset的时候要使用SourceContext.getCheckpoi...

这个BufferingSink实现了CheckpointedFunction接口，它定义了ListState类型的checkpointedState，以及List结构的bufferedElements

flink-jdbc_2.11-1.7.0-sources.jar!/org/apache/flink/api/java/io/jdbc/JDBCOutputFormat.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/datastream/DataStream.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/datastream/DataStream.java

flink-streaming-java_2.11-1.7.0-sources.jar!/org/apache/flink/streaming/api/datastream/DataStream.java

这里使用ExecutionEnvironment的generateSequence方法创建了带NumberSequenceIterator的ParallelIteratorInputFormat

flink-streaming-java_2.11-1.6.2-sources.jar!/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java

RichParallelSourceFunction实现了ParallelSourceFunction接口，同时继承了AbstractRichFunction

flink-streaming-java_2.11-1.6.2-sources.jar!/org/apache/flink/streaming/api/functions/source/SourceFunction.java