ARROW-208: Add checkstyle policy to java project

Author: Tsuyoshi Ozawa <ozawa@apache.org>

Closes #96 from oza/ARROW-208 and squashes the following commits:

809e729 [Tsuyoshi Ozawa] reformatted code in memory and tools dir with IDE
40ee6a3 [Tsuyoshi Ozawa] ARROW-208: Add checkstyle policy to java project

java/memory/src/main/java/io/netty/buffer/ExpandableByteBuf.java

@@ -6,21 +6,23 @@
  * 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
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * 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 io.netty.buffer;
 
 import org.apache.arrow.memory.BufferAllocator;
 
 /**
- * Allows us to decorate ArrowBuf to make it expandable so that we can use them in the context of the Netty framework
+ * Allows us to decorate ArrowBuf to make it expandable so that we can use them in the context of
+ * the Netty framework
  * (thus supporting RPC level memory accounting).
  */
 public class ExpandableByteBuf extends MutableWrappedByteBuf {

java/memory/src/main/java/io/netty/buffer/LargeBuffer.java

@@ -6,21 +6,24 @@
  * 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
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * 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 io.netty.buffer;
 
 /**
- * A MutableWrappedByteBuf that also maintains a metric of the number of huge buffer bytes and counts.
+ * A MutableWrappedByteBuf that also maintains a metric of the number of huge buffer bytes and
+ * counts.
  */
 public class LargeBuffer extends MutableWrappedByteBuf {
+
   public LargeBuffer(ByteBuf buffer) {
     super(buffer);
   }

java/memory/src/main/java/io/netty/buffer/MutableWrappedByteBuf.java

@@ -6,15 +6,16 @@
  * 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
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * 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 io.netty.buffer;
 
 import java.io.IOException;
@@ -26,16 +27,12 @@
 import java.nio.channels.ScatteringByteChannel;
 
 /**
- * This is basically a complete copy of DuplicatedByteBuf. We copy because we want to override some behaviors and make
+ * This is basically a complete copy of DuplicatedByteBuf. We copy because we want to override
+ * some behaviors and make
  * buffer mutable.
  */
 abstract class MutableWrappedByteBuf extends AbstractByteBuf {
 
-  @Override
-  public ByteBuffer nioBuffer(int index, int length) {
-    return unwrap().nioBuffer(index, length);
-  }
-
   ByteBuf buffer;
 
   public MutableWrappedByteBuf(ByteBuf buffer) {
@@ -50,6 +47,11 @@ public MutableWrappedByteBuf(ByteBuf buffer) {
     setIndex(buffer.readerIndex(), buffer.writerIndex());
   }
 
+  @Override
+  public ByteBuffer nioBuffer(int index, int length) {
+    return unwrap().nioBuffer(index, length);
+  }
+
   @Override
   public ByteBuf unwrap() {
     return buffer;

java/memory/src/main/java/io/netty/buffer/PooledByteBufAllocatorL.java

@@ -6,42 +6,44 @@
  * 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
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * 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 io.netty.buffer;
 
-import static org.apache.arrow.memory.util.AssertionUtil.ASSERT_ENABLED;
+import io.netty.util.internal.StringUtil;
+
+import org.apache.arrow.memory.OutOfMemoryException;
 
 import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
 import java.util.concurrent.atomic.AtomicLong;
 
-import org.apache.arrow.memory.OutOfMemoryException;
-
-import io.netty.util.internal.StringUtil;
+import static org.apache.arrow.memory.util.AssertionUtil.ASSERT_ENABLED;
 
 /**
- * The base allocator that we use for all of Arrow's memory management. Returns UnsafeDirectLittleEndian buffers.
+ * The base allocator that we use for all of Arrow's memory management. Returns
+ * UnsafeDirectLittleEndian buffers.
  */
 public class PooledByteBufAllocatorL {
-  private static final org.slf4j.Logger memoryLogger = org.slf4j.LoggerFactory.getLogger("arrow.allocator");
 
-  private static final int MEMORY_LOGGER_FREQUENCY_SECONDS = 60;
+  private static final org.slf4j.Logger memoryLogger = org.slf4j.LoggerFactory.getLogger("arrow" +
+      ".allocator");
 
+  private static final int MEMORY_LOGGER_FREQUENCY_SECONDS = 60;
+  public final UnsafeDirectLittleEndian empty;
   private final AtomicLong hugeBufferSize = new AtomicLong(0);
   private final AtomicLong hugeBufferCount = new AtomicLong(0);
   private final AtomicLong normalBufferSize = new AtomicLong(0);
   private final AtomicLong normalBufferCount = new AtomicLong(0);
-
   private final InnerAllocator allocator;
-  public final UnsafeDirectLittleEndian empty;
 
   public PooledByteBufAllocatorL() {
     allocator = new InnerAllocator();
@@ -78,6 +80,7 @@ public long getNormalBufferCount() {
   }
 
   private static class AccountedUnsafeDirectLittleEndian extends UnsafeDirectLittleEndian {
+
     private final long initialCapacity;
     private final AtomicLong count;
     private final AtomicLong size;
@@ -89,7 +92,8 @@ private AccountedUnsafeDirectLittleEndian(LargeBuffer buf, AtomicLong count, Ato
       this.size = size;
     }
 
-    private AccountedUnsafeDirectLittleEndian(PooledUnsafeDirectByteBuf buf, AtomicLong count, AtomicLong size) {
+    private AccountedUnsafeDirectLittleEndian(PooledUnsafeDirectByteBuf buf, AtomicLong count,
+                                              AtomicLong size) {
       super(buf);
       this.initialCapacity = buf.capacity();
       this.count = count;
@@ -119,6 +123,7 @@ public boolean release(int decrement) {
   }
 
   private class InnerAllocator extends PooledByteBufAllocator {
+
     private final PoolArena<ByteBuffer>[] directArenas;
     private final MemoryStatusThread statusThread;
     private final int chunkSize;
@@ -131,7 +136,8 @@ public InnerAllocator() {
         f.setAccessible(true);
         this.directArenas = (PoolArena<ByteBuffer>[]) f.get(this);
       } catch (Exception e) {
-        throw new RuntimeException("Failure while initializing allocator.  Unable to retrieve direct arenas field.", e);
+        throw new RuntimeException("Failure while initializing allocator.  Unable to retrieve " +
+            "direct arenas field.", e);
       }
 
       this.chunkSize = directArenas[0].chunkSize;
@@ -158,7 +164,8 @@ private UnsafeDirectLittleEndian newDirectBufferL(int initialCapacity, int maxCa
           hugeBufferCount.incrementAndGet();
 
           // logger.debug("Allocating huge buffer of size {}", initialCapacity, new Exception());
-          return new AccountedUnsafeDirectLittleEndian(new LargeBuffer(buf), hugeBufferCount, hugeBufferSize);
+          return new AccountedUnsafeDirectLittleEndian(new LargeBuffer(buf), hugeBufferCount,
+              hugeBufferSize);
         } else {
           // within chunk, use arena.
           ByteBuf buf = directArena.allocate(cache, initialCapacity, maxCapacity);
@@ -173,7 +180,8 @@ private UnsafeDirectLittleEndian newDirectBufferL(int initialCapacity, int maxCa
           normalBufferSize.addAndGet(buf.capacity());
           normalBufferCount.incrementAndGet();
 
-          return new AccountedUnsafeDirectLittleEndian((PooledUnsafeDirectByteBuf) buf, normalBufferCount, normalBufferSize);
+          return new AccountedUnsafeDirectLittleEndian((PooledUnsafeDirectByteBuf) buf,
+              normalBufferCount, normalBufferSize);
         }
 
       } else {
@@ -183,7 +191,8 @@ private UnsafeDirectLittleEndian newDirectBufferL(int initialCapacity, int maxCa
 
     private UnsupportedOperationException fail() {
       return new UnsupportedOperationException(
-          "Arrow requires that the JVM used supports access sun.misc.Unsafe.  This platform didn't provide that functionality.");
+          "Arrow requires that the JVM used supports access sun.misc.Unsafe.  This platform " +
+              "didn't provide that functionality.");
     }
 
     @Override
@@ -203,7 +212,8 @@ public ByteBuf heapBuffer(int initialCapacity, int maxCapacity) {
 
     private void validate(int initialCapacity, int maxCapacity) {
       if (initialCapacity < 0) {
-        throw new IllegalArgumentException("initialCapacity: " + initialCapacity + " (expectd: 0+)");
+        throw new IllegalArgumentException("initialCapacity: " + initialCapacity + " (expectd: " +
+            "0+)");
       }
       if (initialCapacity > maxCapacity) {
         throw new IllegalArgumentException(String.format(
@@ -212,26 +222,6 @@ private void validate(int initialCapacity, int maxCapacity) {
       }
     }
 
-    private class MemoryStatusThread extends Thread {
-
-      public MemoryStatusThread() {
-        super("allocation.logger");
-        this.setDaemon(true);
-      }
-
-      @Override
-      public void run() {
-        while (true) {
-          memoryLogger.trace("Memory Usage: \n{}", PooledByteBufAllocatorL.this.toString());
-          try {
-            Thread.sleep(MEMORY_LOGGER_FREQUENCY_SECONDS * 1000);
-          } catch (InterruptedException e) {
-            return;
-          }
-        }
-      }
-    }
-
     @Override
     public String toString() {
       StringBuilder buf = new StringBuilder();
@@ -256,6 +246,26 @@ public String toString() {
       return buf.toString();
     }
 
+    private class MemoryStatusThread extends Thread {
+
+      public MemoryStatusThread() {
+        super("allocation.logger");
+        this.setDaemon(true);
+      }
+
+      @Override
+      public void run() {
+        while (true) {
+          memoryLogger.trace("Memory Usage: \n{}", PooledByteBufAllocatorL.this.toString());
+          try {
+            Thread.sleep(MEMORY_LOGGER_FREQUENCY_SECONDS * 1000);
+          } catch (InterruptedException e) {
+            return;
+          }
+        }
+      }
+    }
+
 
   }
 }

java/memory/src/main/java/io/netty/buffer/UnsafeDirectLittleEndian.java

@@ -6,9 +6,9 @@
  * 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
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * 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.
@@ -18,22 +18,31 @@
 
 package io.netty.buffer;
 
+import io.netty.util.internal.PlatformDependent;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.ByteOrder;
 import java.util.concurrent.atomic.AtomicLong;
 
-import io.netty.util.internal.PlatformDependent;
-
 /**
- * The underlying class we use for little-endian access to memory. Is used underneath ArrowBufs to abstract away the
+ * The underlying class we use for little-endian access to memory. Is used underneath ArrowBufs
+ * to abstract away the
  * Netty classes and underlying Netty memory management.
  */
 public class UnsafeDirectLittleEndian extends WrappedByteBuf {
+
+  public static final boolean ASSERT_ENABLED;
   private static final boolean NATIVE_ORDER = ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN;
   private static final AtomicLong ID_GENERATOR = new AtomicLong(0);
 
+  static {
+    boolean isAssertEnabled = false;
+    assert isAssertEnabled = true;
+    ASSERT_ENABLED = isAssertEnabled;
+  }
+
   public final long id = ID_GENERATOR.incrementAndGet();
   private final AbstractByteBuf wrapped;
   private final long memoryAddress;
@@ -60,21 +69,22 @@ private UnsafeDirectLittleEndian(AbstractByteBuf buf, boolean fake) {
     this.wrapped = buf;
     this.memoryAddress = buf.memoryAddress();
   }
-    private long addr(int index) {
-        return memoryAddress + index;
-    }
 
-    @Override
-    public long getLong(int index) {
+  private long addr(int index) {
+    return memoryAddress + index;
+  }
+
+  @Override
+  public long getLong(int index) {
 //        wrapped.checkIndex(index, 8);
-        long v = PlatformDependent.getLong(addr(index));
-        return v;
-    }
+    long v = PlatformDependent.getLong(addr(index));
+    return v;
+  }
 
-    @Override
-    public float getFloat(int index) {
-        return Float.intBitsToFloat(getInt(index));
-    }
+  @Override
+  public float getFloat(int index) {
+    return Float.intBitsToFloat(getInt(index));
+  }
 
   @Override
   public ByteBuf slice() {
@@ -259,12 +269,4 @@ public int hashCode() {
     return System.identityHashCode(this);
   }
 
-  public static final boolean ASSERT_ENABLED;
-
-  static {
-    boolean isAssertEnabled = false;
-    assert isAssertEnabled = true;
-    ASSERT_ENABLED = isAssertEnabled;
-  }
-
 }