[HUDI-355] Refactor hudi-common based on new comment and code style rules

hudi-common/src/main/java/org/apache/hudi/avro/MercifulJsonConverter.java

@@ -37,7 +37,7 @@
 import java.util.Map;
 
 /**
- * Converts Json record to Avro Generic Record
+ * Converts Json record to Avro Generic Record.
  */
 public class MercifulJsonConverter {
 
@@ -61,21 +61,21 @@ private static Map<Schema.Type, JsonToAvroFieldProcessor> getFieldTypeProcessors
   }
 
   /**
-   * Uses a default objectMapper to deserialize a json string
+   * Uses a default objectMapper to deserialize a json string.
    */
   public MercifulJsonConverter() {
     this(new ObjectMapper());
   }
 
   /**
-   * Allows a configured ObjectMapper to be passed for converting json records to avro record
+   * Allows a configured ObjectMapper to be passed for converting json records to avro record.
    */
   public MercifulJsonConverter(ObjectMapper mapper) {
     this.mapper = mapper;
   }
 
   /**
-   * Converts json to Avro generic record
+   * Converts json to Avro generic record.
    *
    * @param json Json record
    * @param schema Schema
@@ -133,7 +133,7 @@ private static Object convertJsonToAvroField(Object value, String name, Schema s
   }
 
   /**
-   * Base Class for converting json to avro fields
+   * Base Class for converting json to avro fields.
    */
   private abstract static class JsonToAvroFieldProcessor implements Serializable {
 
@@ -311,7 +311,7 @@ public Pair<Boolean, Object> convert(Object value, String name, Schema schema)
   }
 
   /**
-   * Exception Class for any schema conversion issue
+   * Exception Class for any schema conversion issue.
    */
   public static class HoodieJsonToAvroConversionException extends HoodieException {
 

hudi-common/src/main/java/org/apache/hudi/common/HoodieCleanStat.java

@@ -26,7 +26,7 @@
 import java.util.List;
 
 /**
- * Collects stats about a single partition clean operation
+ * Collects stats about a single partition clean operation.
  */
 public class HoodieCleanStat implements Serializable {
 
@@ -80,6 +80,9 @@ public static HoodieCleanStat.Builder newBuilder() {
     return new Builder();
   }
 
+  /**
+   * A builder used to build {@link HoodieCleanStat}.
+   */
   public static class Builder {
 
     private HoodieCleaningPolicy policy;

hudi-common/src/main/java/org/apache/hudi/common/HoodieJsonPayload.java

@@ -36,6 +36,9 @@
 import java.util.zip.DeflaterOutputStream;
 import java.util.zip.InflaterInputStream;
 
+/**
+ * Hoodie json payload.
+ */
 public class HoodieJsonPayload implements HoodieRecordPayload<HoodieJsonPayload> {
 
   private byte[] jsonDataCompressed;

hudi-common/src/main/java/org/apache/hudi/common/HoodieRollbackStat.java

@@ -26,7 +26,7 @@
 import java.util.stream.Collectors;
 
 /**
- * Collects stats about a single partition clean operation
+ * Collects stats about a single partition clean operation.
  */
 public class HoodieRollbackStat implements Serializable {
 
@@ -66,6 +66,9 @@ public static HoodieRollbackStat.Builder newBuilder() {
     return new Builder();
   }
 
+  /**
+   * A builder used to build {@link HoodieRollbackStat}.
+   */
   public static class Builder {
 
     private List<String> successDeleteFiles;

hudi-common/src/main/java/org/apache/hudi/common/SerializableConfiguration.java

@@ -25,6 +25,9 @@
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 
+/**
+ * A wrapped configuration which can be serialized.
+ */
 public class SerializableConfiguration implements Serializable {
 
   private transient Configuration configuration;

hudi-common/src/main/java/org/apache/hudi/common/model/ActionType.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * The supported action types.
+ */
 public enum ActionType {
   commit, savepoint, compaction, clean, rollback
 }

hudi-common/src/main/java/org/apache/hudi/common/model/CompactionOperation.java

@@ -34,8 +34,7 @@
 
 /**
  * Encapsulates all the needed information about a compaction and make a decision whether this compaction is effective
- * or not
- *
+ * or not.
  */
 public class CompactionOperation implements Serializable {
 
@@ -118,7 +117,7 @@ public Option<HoodieDataFile> getBaseFile(String basePath, String partitionPath)
   }
 
   /**
-   * Convert Avro generated Compaction operation to POJO for Spark RDD operation
+   * Convert Avro generated Compaction operation to POJO for Spark RDD operation.
    * 
    * @param operation Hoodie Compaction Operation
    * @return

hudi-common/src/main/java/org/apache/hudi/common/model/FileSlice.java

@@ -27,22 +27,22 @@
 
 /**
  * Within a file group, a slice is a combination of data file written at a commit time and list of log files, containing
- * changes to the data file from that commit time
+ * changes to the data file from that commit time.
  */
 public class FileSlice implements Serializable {
 
   /**
-   * File Group Id of the Slice
+   * File Group Id of the Slice.
    */
   private HoodieFileGroupId fileGroupId;
 
   /**
-   * Point in the timeline, at which the slice was created
+   * Point in the timeline, at which the slice was created.
    */
   private String baseInstantTime;
 
   /**
-   * data file, with the compacted data, for this slice
+   * data file, with the compacted data, for this slice.
    */
   private HoodieDataFile dataFile;
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieArchivedLogFile.java

@@ -21,6 +21,9 @@
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.Path;
 
+/**
+ * The hoodie archived log file.
+ */
 public class HoodieArchivedLogFile extends HoodieLogFile {
 
   public static final String ARCHIVE_EXTENSION = ".archive";

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieCleaningPolicy.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * Hoodie cleaning policies.
+ */
 public enum HoodieCleaningPolicy {
   KEEP_LATEST_FILE_VERSIONS, KEEP_LATEST_COMMITS
 }

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieDataFile.java

@@ -26,6 +26,9 @@
 import java.io.Serializable;
 import java.util.Objects;
 
+/**
+ * Hoodie data file.
+ */
 public class HoodieDataFile implements Serializable {
 
   private transient FileStatus fileStatus;

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileFormat.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * Hoodie file format.
+ */
 public enum HoodieFileFormat {
   PARQUET(".parquet"), HOODIE_LOG(".log");
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileGroup.java

@@ -30,7 +30,7 @@
 import java.util.stream.Stream;
 
 /**
- * A set of data/base files + set of log files, that make up an unit for all operations
+ * A set of data/base files + set of log files, that make up an unit for all operations.
  */
 public class HoodieFileGroup implements Serializable {
 
@@ -39,7 +39,7 @@ public static Comparator<String> getReverseCommitTimeComparator() {
   }
 
   /**
-   * file group id
+   * file group id.
    */
   private final HoodieFileGroupId fileGroupId;
 
@@ -49,12 +49,12 @@ public static Comparator<String> getReverseCommitTimeComparator() {
   private final TreeMap<String, FileSlice> fileSlices;
 
   /**
-   * Timeline, based on which all getter work
+   * Timeline, based on which all getter work.
    */
   private final HoodieTimeline timeline;
 
   /**
-   * The last completed instant, that acts as a high watermark for all getters
+   * The last completed instant, that acts as a high watermark for all getters.
    */
   private final Option<HoodieInstant> lastInstant;
 
@@ -71,7 +71,7 @@ public HoodieFileGroup(HoodieFileGroupId fileGroupId, HoodieTimeline timeline) {
 
   /**
    * Potentially add a new file-slice by adding base-instant time A file-slice without any data-file and log-files can
-   * exist (if a compaction just got requested)
+   * exist (if a compaction just got requested).
    */
   public void addNewFileSliceAtInstant(String baseInstantTime) {
     if (!fileSlices.containsKey(baseInstantTime)) {
@@ -80,7 +80,7 @@ public void addNewFileSliceAtInstant(String baseInstantTime) {
   }
 
   /**
-   * Add a new datafile into the file group
+   * Add a new datafile into the file group.
    */
   public void addDataFile(HoodieDataFile dataFile) {
     if (!fileSlices.containsKey(dataFile.getCommitTime())) {
@@ -90,7 +90,7 @@ public void addDataFile(HoodieDataFile dataFile) {
   }
 
   /**
-   * Add a new log file into the group
+   * Add a new log file into the group.
    */
   public void addLogFile(HoodieLogFile logFile) {
     if (!fileSlices.containsKey(logFile.getBaseCommitTime())) {
@@ -109,7 +109,7 @@ public HoodieFileGroupId getFileGroupId() {
 
   /**
    * A FileSlice is considered committed, if one of the following is true - There is a committed data file - There are
-   * some log files, that are based off a commit or delta commit
+   * some log files, that are based off a commit or delta commit.
    */
   private boolean isFileSliceCommitted(FileSlice slice) {
     String maxCommitTime = lastInstant.get().getTimestamp();
@@ -119,14 +119,14 @@ private boolean isFileSliceCommitted(FileSlice slice) {
   }
 
   /**
-   * Get all the the file slices including in-flight ones as seen in underlying file-system
+   * Get all the the file slices including in-flight ones as seen in underlying file-system.
    */
   public Stream<FileSlice> getAllFileSlicesIncludingInflight() {
     return fileSlices.entrySet().stream().map(Map.Entry::getValue);
   }
 
   /**
-   * Get latest file slices including in-flight ones
+   * Get latest file slices including in-flight ones.
    */
   public Option<FileSlice> getLatestFileSlicesIncludingInflight() {
     return Option.fromJavaOptional(getAllFileSlicesIncludingInflight().findFirst());
@@ -143,7 +143,7 @@ public Stream<FileSlice> getAllFileSlices() {
   }
 
   /**
-   * Gets the latest slice - this can contain either
+   * Gets the latest slice - this can contain either.
    * <p>
    * - just the log files without data file - (or) data file with 0 or more log files
    */
@@ -153,22 +153,22 @@ public Option<FileSlice> getLatestFileSlice() {
   }
 
   /**
-   * Gets the latest data file
+   * Gets the latest data file.
    */
   public Option<HoodieDataFile> getLatestDataFile() {
     return Option.fromJavaOptional(getAllDataFiles().findFirst());
   }
 
   /**
-   * Obtain the latest file slice, upto a commitTime i.e <= maxCommitTime
+   * Obtain the latest file slice, upto a commitTime i.e <= maxCommitTime.
    */
   public Option<FileSlice> getLatestFileSliceBeforeOrOn(String maxCommitTime) {
     return Option.fromJavaOptional(getAllFileSlices().filter(slice -> HoodieTimeline
         .compareTimestamps(slice.getBaseInstantTime(), maxCommitTime, HoodieTimeline.LESSER_OR_EQUAL)).findFirst());
   }
 
   /**
-   * Obtain the latest file slice, upto a commitTime i.e < maxInstantTime
+   * Obtain the latest file slice, upto a commitTime i.e < maxInstantTime.
    * 
    * @param maxInstantTime Max Instant Time
    * @return
@@ -185,7 +185,7 @@ public Option<FileSlice> getLatestFileSliceInRange(List<String> commitRange) {
   }
 
   /**
-   * Stream of committed data files, sorted reverse commit time
+   * Stream of committed data files, sorted reverse commit time.
    */
   public Stream<HoodieDataFile> getAllDataFiles() {
     return getAllFileSlices().filter(slice -> slice.getDataFile().isPresent()).map(slice -> slice.getDataFile().get());

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileGroupId.java

@@ -22,7 +22,7 @@
 import java.util.Objects;
 
 /**
- * Unique ID to identify a file-group in a data-set
+ * Unique ID to identify a file-group in a data-set.
  */
 public class HoodieFileGroupId implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieKey.java

@@ -26,7 +26,8 @@
  * HoodieKey consists of
  * <p>
  * - recordKey : a recordKey that acts as primary key for a record - partitionPath : path to the partition that contains
- * the record
+ * the record.
+ * - partitionPath : the partition path of a record.
  */
 public class HoodieKey implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieLogFile.java

@@ -125,7 +125,7 @@ public static Comparator<HoodieLogFile> getReverseLogFileComparator() {
   }
 
   /**
-   * Comparator to order log-files
+   * Comparator to order log-files.
    */
   public static class LogFileComparator implements Comparator<HoodieLogFile>, Serializable {