[Review][CARBONDATA-1386] fixed findbugs errors in carbondata-core

fixed findbugs errors in carbondata-core

This closes apache#1263

Author: sraghunandan

common/src/main/java/org/apache/carbondata/common/logging/impl/ExtendedRollingFileAppender.java

@@ -74,6 +74,10 @@ public boolean accept(File file) {
         }
       });
 
+      if (null == files) {
+        return;
+      }
+
       int backupFiles = files.length - 1;
 
       if (backupFiles <= maxBackupIndex) {

core/src/main/java/org/apache/carbondata/core/cache/dictionary/AbstractDictionaryCache.java

@@ -173,7 +173,7 @@ private CarbonFile getDictionaryMetaCarbonFile(
   protected long getSortIndexSize(long numOfRecords) {
     // sort index has sort index and reverse sort index,each is 4 byte integer.
     // 32 byte is the array header of both the integer arrays
-    return numOfRecords * ObjectSizeCalculator.estimate(new Integer(0), 16) * 2 + 32;
+    return numOfRecords * ObjectSizeCalculator.estimate(0, 16) * 2 + 32;
   }
 
   /**

core/src/main/java/org/apache/carbondata/core/cache/dictionary/DoubleArrayTrieDictionary.java

@@ -35,10 +35,10 @@
  */
 
 public class DoubleArrayTrieDictionary {
-  public static final byte[] HEAD_MAGIC = new byte[]{
+  private static final byte[] HEAD_MAGIC = new byte[]{
       0x44, 0x41, 0x54, 0x54, 0x72, 0x69, 0x65, 0x44, 0x69, 0x63, 0x74
   }; // "DATTrieDict"
-  public static final int HEAD_LEN = HEAD_MAGIC.length;
+  private static final int HEAD_LEN = HEAD_MAGIC.length;
 
   private static final int INIT_CAPA_VALUE = 256;  // init len of double array
   private static final int BASE_ROOT_VALUE = 1;    // root base value of trie root
@@ -168,7 +168,7 @@ private TreeSet<Integer> getChildren(int pos) {
         return null;
       }
       if (check[cpos] == pos) {
-        children.add(new Integer(i));
+        children.add(i);
       }
     }
     return children;
@@ -227,9 +227,9 @@ private int findAvailableHop(int value) {
   private int conflict(int start, int bKey) {
     int from = start;
     TreeSet<Integer> children = getChildren(from);
-    children.add(new Integer(bKey));
+    children.add(bKey);
     int newBasePos = findFreeRoom(children);
-    children.remove(new Integer(bKey));
+    children.remove(bKey);
 
     int oldBasePos = base[start];
     base[start] = newBasePos;
@@ -351,7 +351,7 @@ public void write(DataOutputStream out) throws IOException {
    */
   public void read(DataInputStream in) throws IOException {
     byte[] header = new byte[HEAD_LEN];
-    in.read(header);
+    in.readFully(header);
     int comp = 0;
     for (int i = 0; i < HEAD_LEN; i++) {
       comp = HEAD_MAGIC[i] - header[i];

core/src/main/java/org/apache/carbondata/core/cache/dictionary/ReverseDictionaryCache.java

@@ -58,7 +58,7 @@ public class ReverseDictionaryCache<K extends DictionaryColumnUniqueIdentifier,
 
   private static final long sizeOfHashMapNode = ObjectSizeCalculator.estimate(new
       DictionaryByteArrayWrapper(new byte[0]), 16) +
-      ObjectSizeCalculator.estimate(new Integer(0), 16);
+      ObjectSizeCalculator.estimate(0, 16);
 
   private static final long byteArraySize = ObjectSizeCalculator.estimate(new byte[0], 16);
 

core/src/main/java/org/apache/carbondata/core/constants/CarbonCommonConstants.java

@@ -189,8 +189,7 @@ public final class CarbonCommonConstants {
   /**
    * Bytes for string 0, it is used in codegen in case of null values.
    */
-  public static final byte[] ZERO_BYTE_ARRAY = "0".getBytes();
-
+  public static final byte[] ZERO_BYTE_ARRAY = "0".getBytes(Charset.forName(DEFAULT_CHARSET));
   /**
    * FILE STATUS IN-PROGRESS
    */

core/src/main/java/org/apache/carbondata/core/datamap/DataMapStoreManager.java

@@ -92,7 +92,7 @@ public TableDataMap createAndRegisterDataMap(AbsoluteTableIdentifier identifier,
     try {
       DataMapFactory dataMapFactory = factoryClass.newInstance();
       dataMapFactory.init(identifier, dataMapName);
-      dataMap = new TableDataMap(identifier, dataMapName, dataMapFactory);
+      dataMap = new TableDataMap(dataMapName, dataMapFactory);
     } catch (Exception e) {
       LOGGER.error(e);
       throw new RuntimeException(e);
@@ -119,7 +119,7 @@ private TableDataMap getAbstractTableDataMap(String dataMapName,
    * @param dataMapName
    */
   public void clearDataMap(AbsoluteTableIdentifier identifier, String dataMapName) {
-    List<TableDataMap> tableDataMaps = allDataMaps.get(identifier);
+    List<TableDataMap> tableDataMaps = allDataMaps.get(identifier.uniqueName());
     if (tableDataMaps != null) {
       int i = 0;
       for (TableDataMap tableDataMap: tableDataMaps) {

core/src/main/java/org/apache/carbondata/core/datamap/TableDataMap.java

@@ -25,7 +25,6 @@
 import org.apache.carbondata.core.events.ChangeEvent;
 import org.apache.carbondata.core.events.EventListener;
 import org.apache.carbondata.core.indexstore.Blocklet;
-import org.apache.carbondata.core.metadata.AbsoluteTableIdentifier;
 import org.apache.carbondata.core.scan.filter.resolver.FilterResolverIntf;
 
 /**
@@ -34,18 +33,15 @@
  */
 public final class TableDataMap implements EventListener {
 
-  private AbsoluteTableIdentifier identifier;
-
   private String dataMapName;
 
   private DataMapFactory dataMapFactory;
 
   /**
    * It is called to initialize and load the required table datamap metadata.
    */
-  public TableDataMap(AbsoluteTableIdentifier identifier, String dataMapName,
+  public TableDataMap(String dataMapName,
       DataMapFactory dataMapFactory) {
-    this.identifier = identifier;
     this.dataMapName = dataMapName;
     this.dataMapFactory = dataMapFactory;
   }

core/src/main/java/org/apache/carbondata/core/datastore/AbstractBlockIndexStoreCache.java

@@ -41,10 +41,7 @@
  */
 public abstract class AbstractBlockIndexStoreCache<K, V>
     implements Cache<TableBlockUniqueIdentifier, AbstractIndex> {
-  /**
-   * carbon store path
-   */
-  protected String carbonStorePath;
+
   /**
    * CarbonLRU cache
    */
@@ -70,8 +67,7 @@ public abstract class AbstractBlockIndexStoreCache<K, V>
    */
   protected Map<String, Object> segmentIDLock;
 
-  public AbstractBlockIndexStoreCache(String carbonStorePath, CarbonLRUCache lruCache) {
-    this.carbonStorePath = carbonStorePath;
+  public AbstractBlockIndexStoreCache(CarbonLRUCache lruCache) {
     this.lruCache = lruCache;
     blockInfoLock = new ConcurrentHashMap<BlockInfo, Object>();
     segmentIDLock = new ConcurrentHashMap<String, Object>();

core/src/main/java/org/apache/carbondata/core/datastore/BlockIndexStore.java

@@ -59,7 +59,7 @@ public class BlockIndexStore<K, V> extends AbstractBlockIndexStoreCache<K, V> {
   private static final LogService LOGGER =
       LogServiceFactory.getLogService(BlockIndexStore.class.getName());
   public BlockIndexStore(String carbonStorePath, CarbonLRUCache lruCache) {
-    super(carbonStorePath, lruCache);
+    super(lruCache);
   }
 
   /**

core/src/main/java/org/apache/carbondata/core/datastore/block/TableBlockInfo.java

@@ -190,13 +190,15 @@ public long getBlockLength() {
     if (blockLength != other.blockLength) {
       return false;
     }
-    if (filePath == null && other.filePath != null) {
-      return false;
-    } else if (filePath != null && other.filePath == null) {
-      return false;
-    } else if (!filePath.equals(other.filePath)) {
+
+    if (null == filePath || null == other.filePath) {
+      return  false;
+    }
+
+    if (!filePath.equals(other.filePath)) {
       return false;
     }
+
     if (blockletInfos.getStartBlockletNumber() != other.blockletInfos.getStartBlockletNumber()) {
       return false;
     }