Clean up MessageSerializer to simplify subclasses

By replacing MessageSerializer with an abstract class, methods which should just call other methods in the same class are now fixed, and subclasses only have to override a single abstract method instead of multiple.
bitcoinj · Oct 18, 2015 · df56a23 · df56a23
1 parent 4375f66
commit df56a23
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Showing 4 changed files with 44 additions and 59 deletions.
diff --git a/core/src/main/java/org/bitcoinj/core/BitcoinSerializer.java b/core/src/main/java/org/bitcoinj/core/BitcoinSerializer.java
@@ -41,7 +41,7 @@
  * <li>Message.bitcoinSerializeToStream() needs to be properly subclassed</li>
  * </ul>
  */
-public class BitcoinSerializer implements MessageSerializer {
+public class BitcoinSerializer extends MessageSerializer {
     private static final Logger log = LoggerFactory.getLogger(BitcoinSerializer.class);
     private static final int COMMAND_LEN = 12;
 
@@ -266,16 +266,7 @@ public Message makeAlertMessage(byte[] payloadBytes) throws ProtocolException {
      * serialization format support.
      */
     @Override
-    public Block makeBlock(byte[] payloadBytes) throws ProtocolException {
-        return new Block(params, payloadBytes, this, payloadBytes.length);
-    }
-
-    /**
-     * Make a block from the payload. Extension point for alternative
-     * serialization format support.
-     */
-    @Override
-    public Block makeBlock(byte[] payloadBytes, int length) throws ProtocolException {
+    public Block makeBlock(final byte[] payloadBytes, final int length) throws ProtocolException {
         return new Block(params, payloadBytes, this, length);
     }
 
@@ -319,16 +310,6 @@ public Transaction makeTransaction(byte[] payloadBytes, int offset,
         return tx;
     }
 
-    @Override
-    public Transaction makeTransaction(byte[] payloadBytes) throws ProtocolException {
-        return makeTransaction(payloadBytes, 0, payloadBytes.length, null);
-    }
-
-    @Override
-    public Transaction makeTransaction(byte[] payloadBytes, int offset) throws ProtocolException {
-        return makeTransaction(payloadBytes, offset, payloadBytes.length, null);
-    }
-
     @Override
     public void seekPastMagicBytes(ByteBuffer in) throws BufferUnderflowException {
         int magicCursor = 3;  // Which byte of the magic we're looking for currently.

diff --git a/core/src/main/java/org/bitcoinj/core/Block.java b/core/src/main/java/org/bitcoinj/core/Block.java
@@ -121,8 +121,9 @@ public Block(NetworkParameters params, byte[] payloadBytes) throws ProtocolExcep
     }
 
     /**
-     * Contruct a block object from the Bitcoin wire format.
+     * Construct a block object from the Bitcoin wire format.
      * @param params NetworkParameters object.
+     * @param payloadBytes the payload to extract the block from.
      * @param serializer the serializer to use for this message.
      * @param length The length of message if known.  Usually this is provided when deserializing of the wire
      * as the length will be provided as part of the header.  If unknown then set to Message.UNKNOWN_LENGTH
@@ -964,4 +965,14 @@ boolean isHeaderBytesValid() {
     boolean isTransactionBytesValid() {
         return transactionBytesValid;
     }
+
+    /**
+     * Return whether this block contains any transactions.
+     * 
+     * @return  true if the block contains transactions, false otherwise (is
+     * purely a header).
+     */
+    public boolean hasTransactions() {
+        return !this.transactions.isEmpty();
+    }
 }
diff --git a/core/src/main/java/org/bitcoinj/core/DummySerializer.java b/core/src/main/java/org/bitcoinj/core/DummySerializer.java
@@ -25,7 +25,7 @@
  * Dummy serializer used ONLY for objects which do not have network parameters
  * set.
  */
-class DummySerializer implements MessageSerializer {
+class DummySerializer extends MessageSerializer {
     public static final DummySerializer DEFAULT = new DummySerializer();
 
     private static final String DEFAULT_EXCEPTION_MESSAGE = "Dummy serializer cannot serialize/deserialize objects as it does not know which network they belong to.";
@@ -63,11 +63,6 @@ public Message makeAlertMessage(byte[] payloadBytes) throws UnsupportedOperation
         throw new UnsupportedOperationException(DEFAULT_EXCEPTION_MESSAGE);
     }
 
-    @Override
-    public Block makeBlock(byte[] payloadBytes) throws UnsupportedOperationException {
-        throw new UnsupportedOperationException(DEFAULT_EXCEPTION_MESSAGE);
-    }
-
     @Override
     public Block makeBlock(byte[] payloadBytes, int length) throws UnsupportedOperationException {
         throw new UnsupportedOperationException(DEFAULT_EXCEPTION_MESSAGE);
@@ -93,16 +88,6 @@ public Transaction makeTransaction(byte[] payloadBytes, int offset, int length,
         throw new UnsupportedOperationException(DEFAULT_EXCEPTION_MESSAGE);
     }
 
-    @Override
-    public Transaction makeTransaction(byte[] payloadBytes) throws UnsupportedOperationException {
-        return makeTransaction(payloadBytes, 0, payloadBytes.length, null);
-    }
-
-    @Override
-    public Transaction makeTransaction(byte[] payloadBytes, int offset) throws UnsupportedOperationException {
-        return makeTransaction(payloadBytes, offset, payloadBytes.length, null);
-    }
-
     @Override
     public void seekPastMagicBytes(ByteBuffer in) throws BufferUnderflowException {
         throw new UnsupportedOperationException(DEFAULT_EXCEPTION_MESSAGE);

diff --git a/core/src/main/java/org/bitcoinj/core/MessageSerializer.java b/core/src/main/java/org/bitcoinj/core/MessageSerializer.java
@@ -27,71 +27,75 @@
  * Generic interface for classes which serialize/deserialize messages. Implementing
  * classes should be immutable.
  */
-public interface MessageSerializer {
+public abstract class MessageSerializer {
 
     /**
      * Reads a message from the given ByteBuffer and returns it.
      */
-    Message deserialize(ByteBuffer in) throws ProtocolException, IOException, UnsupportedOperationException;
+    public abstract Message deserialize(ByteBuffer in) throws ProtocolException, IOException, UnsupportedOperationException;
 
     /**
      * Deserializes only the header in case packet meta data is needed before decoding
      * the payload. This method assumes you have already called seekPastMagicBytes()
      */
-    BitcoinSerializer.BitcoinPacketHeader deserializeHeader(ByteBuffer in) throws ProtocolException, IOException, UnsupportedOperationException;
+    public abstract BitcoinSerializer.BitcoinPacketHeader deserializeHeader(ByteBuffer in) throws ProtocolException, IOException, UnsupportedOperationException;
 
     /**
      * Deserialize payload only.  You must provide a header, typically obtained by calling
      * {@link BitcoinSerializer#deserializeHeader}.
      */
-    Message deserializePayload(BitcoinSerializer.BitcoinPacketHeader header, ByteBuffer in) throws ProtocolException, BufferUnderflowException, UnsupportedOperationException;
+    public abstract Message deserializePayload(BitcoinSerializer.BitcoinPacketHeader header, ByteBuffer in) throws ProtocolException, BufferUnderflowException, UnsupportedOperationException;
 
     /**
      * Whether the serializer will produce cached mode Messages
      */
-    boolean isParseRetainMode();
+    public abstract boolean isParseRetainMode();
 
     /**
      * Make an address message from the payload. Extension point for alternative
      * serialization format support.
      */
-    AddressMessage makeAddressMessage(byte[] payloadBytes, int length) throws ProtocolException, UnsupportedOperationException;
+    public abstract AddressMessage makeAddressMessage(byte[] payloadBytes, int length) throws ProtocolException, UnsupportedOperationException;
 
     /**
      * Make an alert message from the payload. Extension point for alternative
      * serialization format support.
      */
-    Message makeAlertMessage(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+    public abstract Message makeAlertMessage(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+
 
     /**
-     * Make a block from the payload. Extension point for alternative
-     * serialization format support.
+     * Make a block from the payload, using an offset of zero and the payload
+     * length as block length.
      */
-    Block makeBlock(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+    public final Block makeBlock(byte[] payloadBytes) throws ProtocolException {
+        return makeBlock(payloadBytes, payloadBytes.length);
+    }
 
     /**
-     * Make a block from the payload. Extension point for alternative
+     * Make a block from the payload, using an offset of zero and the provided
+     * length as block length. Extension point for alternative
      * serialization format support.
      */
-    Block makeBlock(byte[] payloadBytes, int length) throws ProtocolException, UnsupportedOperationException;
+    public abstract Block makeBlock(byte[] payloadBytes, int length) throws ProtocolException;
 
     /**
      * Make an filter message from the payload. Extension point for alternative
      * serialization format support.
      */
-    Message makeBloomFilter(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+    public abstract Message makeBloomFilter(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
 
     /**
      * Make a filtered block from the payload. Extension point for alternative
      * serialization format support.
      */
-    FilteredBlock makeFilteredBlock(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+    public abstract FilteredBlock makeFilteredBlock(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
 
     /**
      * Make an inventory message from the payload. Extension point for alternative
      * serialization format support.
      */
-    InventoryMessage makeInventoryMessage(byte[] payloadBytes, int length) throws ProtocolException, UnsupportedOperationException;
+    public abstract InventoryMessage makeInventoryMessage(byte[] payloadBytes, int length) throws ProtocolException, UnsupportedOperationException;
 
     /**
      * Make a transaction from the payload. Extension point for alternative
@@ -102,7 +106,7 @@ public interface MessageSerializer {
      * serializer (i.e. for messages with no network parameters), or because
      * it does not support deserializing transactions.
      */
-    Transaction makeTransaction(byte[] payloadBytes, int offset, int length, byte[] hash) throws ProtocolException, UnsupportedOperationException;
+    public abstract Transaction makeTransaction(byte[] payloadBytes, int offset, int length, byte[] hash) throws ProtocolException, UnsupportedOperationException;
 
     /**
      * Make a transaction from the payload. Extension point for alternative
@@ -113,7 +117,9 @@ public interface MessageSerializer {
      * serializer (i.e. for messages with no network parameters), or because
      * it does not support deserializing transactions.
      */
-    Transaction makeTransaction(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException;
+    public final Transaction makeTransaction(byte[] payloadBytes) throws ProtocolException, UnsupportedOperationException {
+        return makeTransaction(payloadBytes, 0);
+    }
 
     /**
      * Make a transaction from the payload. Extension point for alternative
@@ -124,9 +130,11 @@ public interface MessageSerializer {
      * serializer (i.e. for messages with no network parameters), or because
      * it does not support deserializing transactions.
      */
-    Transaction makeTransaction(byte[] payloadBytes, int offset) throws ProtocolException, UnsupportedOperationException;
+    public final Transaction makeTransaction(byte[] payloadBytes, int offset) throws ProtocolException {
+        return makeTransaction(payloadBytes, offset, payloadBytes.length, null);
+    }
 
-    void seekPastMagicBytes(ByteBuffer in) throws BufferUnderflowException;
+    public abstract void seekPastMagicBytes(ByteBuffer in) throws BufferUnderflowException;
 
     /**
      * Writes message to to the output stream.
@@ -136,7 +144,7 @@ public interface MessageSerializer {
      * serializer (i.e. for messages with no network parameters), or because
      * it does not support serializing the given message.
      */
-    void serialize(String name, byte[] message, OutputStream out) throws IOException, UnsupportedOperationException;
+    public abstract void serialize(String name, byte[] message, OutputStream out) throws IOException, UnsupportedOperationException;
 
     /**
      * Writes message to to the output stream.
@@ -146,6 +154,6 @@ public interface MessageSerializer {
      * serializer (i.e. for messages with no network parameters), or because
      * it does not support serializing the given message.
      */
-    void serialize(Message message, OutputStream out) throws IOException, UnsupportedOperationException;
+    public abstract void serialize(Message message, OutputStream out) throws IOException, UnsupportedOperationException;
 
 }