Message: extract interface, add BaseMessage abstract class

core/src/main/java/org/bitcoinj/core/AddressMessage.java

@@ -26,7 +26,7 @@ import java.util.List;
  * Abstract superclass for address messages on the P2P network, which contain network addresses of other peers. This is
  * one of the ways peers can find each other without using the {@link PeerDiscovery} mechanism.
  */
-public abstract class AddressMessage extends Message {
+public abstract class AddressMessage extends BaseMessage {
 
     protected static final long MAX_ADDRESSES = 1000;
     protected List<PeerAddress> addresses;

core/src/main/java/org/bitcoinj/core/BaseMessage.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright by the original author or authors.
+ *
+ * Licensed 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
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.bitcoinj.core;
+
+import org.bitcoinj.base.Sha256Hash;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+
+/**
+ * A Message is a data structure that can be serialized/deserialized using the Bitcoin serialization format.
+ * Specific types of messages that are used both in the blockchain, and on the wire, are derived from this
+ * class.
+ * <p>
+ * Instances of this class are not safe for use by multiple threads.
+ */
+public abstract class BaseMessage implements Message {
+    private static final Logger log = LoggerFactory.getLogger(BaseMessage.class);
+
+    protected final MessageSerializer serializer;
+
+    protected BaseMessage() {
+        this.serializer = DummySerializer.DEFAULT;
+    }
+
+    protected BaseMessage(MessageSerializer serializer) {
+        this.serializer = serializer;
+    }
+
+    /**
+     * @param payload Bitcoin protocol formatted byte array containing message content.
+     * @param serializer the serializer to use for this message.
+     * @throws ProtocolException
+     */
+    protected BaseMessage(ByteBuffer payload, MessageSerializer serializer) throws ProtocolException {
+        this.serializer = serializer;
+
+        try {
+            parse(payload);
+        } catch(BufferUnderflowException e) {
+            throw new ProtocolException(e);
+        }
+    }
+
+    protected BaseMessage(ByteBuffer payload) throws ProtocolException {
+        this(payload, DummySerializer.DEFAULT);
+    }
+
+    // These methods handle the serialization/deserialization using the custom Bitcoin protocol.
+
+    protected abstract void parse(ByteBuffer payload) throws BufferUnderflowException, ProtocolException;
+
+    /**
+     * <p>Serialize this message to a byte array that conforms to the bitcoin wire protocol.</p>
+     *
+     * @return serialized data in Bitcoin protocol format
+     */
+    @Override
+    public final byte[] bitcoinSerialize() {
+        // No cached array available so serialize parts by stream.
+        ByteArrayOutputStream stream = new ByteArrayOutputStream(100); // initial size just a guess
+        try {
+            bitcoinSerializeToStream(stream);
+        } catch (IOException e) {
+            // Cannot happen, we are serializing to a memory stream.
+        }
+        return stream.toByteArray();
+    }
+
+    /** @deprecated use {@link #bitcoinSerialize()} */
+    @Deprecated
+    public byte[] unsafeBitcoinSerialize() {
+        return bitcoinSerialize();
+    }
+
+    /**
+     * Serializes this message to the provided stream. If you just want the raw bytes use bitcoinSerialize().
+     */
+    protected void bitcoinSerializeToStream(OutputStream stream) throws IOException {
+        log.error("Error: {} class has not implemented bitcoinSerializeToStream method.  Generating message with no payload", getClass());
+    }
+
+    /** @deprecated use {@link Transaction#getTxId()}, {@link Block#getHash()}, {@link FilteredBlock#getHash()} or {@link TransactionOutPoint#hash()} */
+    @Deprecated
+    public Sha256Hash getHash() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Return the size of the serialized message. Note that if the message was deserialized from a payload, this
+     * size can differ from the size of the original payload.
+     * @return size of this object when serialized (in bytes)
+     */
+    @Override
+    public int getMessageSize() {
+        return bitcoinSerialize().length;
+    }
+}

core/src/main/java/org/bitcoinj/core/Block.java

@@ -70,7 +70,7 @@ import static org.bitcoinj.base.internal.Preconditions.checkState;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class Block extends Message {
+public class Block extends BaseMessage {
     /**
      * Flags used to control which elements of block validation are done on
      * received blocks.

core/src/main/java/org/bitcoinj/core/BloomFilter.java

@@ -55,7 +55,7 @@ import static org.bitcoinj.base.internal.Preconditions.checkArgument;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class BloomFilter extends Message {
+public class BloomFilter extends BaseMessage {
     /** The BLOOM_UPDATE_* constants control when the bloom filter is auto-updated by the peer using
         it as a filter, either never, for all outputs or only for P2PK outputs (default) */
     public enum BloomUpdate {

core/src/main/java/org/bitcoinj/core/EmptyMessage.java

@@ -28,7 +28,7 @@ import java.nio.ByteBuffer;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public abstract class EmptyMessage extends Message {
+public abstract class EmptyMessage extends BaseMessage {
 
     public EmptyMessage() {
         super();

core/src/main/java/org/bitcoinj/core/FeeFilterMessage.java

@@ -34,7 +34,7 @@ import static org.bitcoinj.base.internal.Preconditions.check;
  *
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class FeeFilterMessage extends Message {
+public class FeeFilterMessage extends BaseMessage {
     private Coin feeRate;
 
     public FeeFilterMessage(ByteBuffer payload) {

core/src/main/java/org/bitcoinj/core/FilteredBlock.java

@@ -37,7 +37,7 @@ import java.util.Objects;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class FilteredBlock extends Message {
+public class FilteredBlock extends BaseMessage {
     private Block header;
 
     private PartialMerkleTree merkleTree;

core/src/main/java/org/bitcoinj/core/GetBlocksMessage.java

@@ -34,7 +34,7 @@ import static org.bitcoinj.base.internal.Preconditions.check;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class GetBlocksMessage extends Message {
+public class GetBlocksMessage extends BaseMessage {
 
     protected long version;
     protected BlockLocator locator;

core/src/main/java/org/bitcoinj/core/HeadersMessage.java

@@ -38,7 +38,7 @@ import static org.bitcoinj.base.internal.Preconditions.check;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class HeadersMessage extends Message {
+public class HeadersMessage extends BaseMessage {
     private static final Logger log = LoggerFactory.getLogger(HeadersMessage.class);
 
     // The main client will never send us more than this number of headers.

core/src/main/java/org/bitcoinj/core/ListMessage.java

@@ -37,7 +37,7 @@ import static org.bitcoinj.base.internal.Preconditions.check;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public abstract class ListMessage extends Message {
+public abstract class ListMessage extends BaseMessage {
 
     // For some reason the compiler complains if this is inside InventoryItem
     protected List<InventoryItem> items;

core/src/main/java/org/bitcoinj/core/Message.java

@@ -1,6 +1,5 @@
 /*
- * Copyright 2011 Google Inc.
- * Copyright 2014 Andreas Schildbach
+ * Copyright by the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,102 +16,28 @@
 
 package org.bitcoinj.core;
 
-import org.bitcoinj.base.Sha256Hash;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.nio.BufferUnderflowException;
-import java.nio.ByteBuffer;
-
 /**
- * <p>A Message is a data structure that can be serialized/deserialized using the Bitcoin serialization format.
- * Specific types of messages that are used both in the block chain, and on the wire, are derived from this
- * class.</p>
- * 
- * <p>Instances of this class are not safe for use by multiple threads.</p>
+ * A Message is a data structure that can be serialized/deserialized using the Bitcoin serialization format.
+ * Classes that can be serialized to the blockchain or P2P protocol should implement this interface.
  */
-public abstract class Message {
-    private static final Logger log = LoggerFactory.getLogger(Message.class);
-
-    public static final int MAX_SIZE = 0x02000000; // 32MB
-
-    protected final MessageSerializer serializer;
-
-    protected Message() {
-        this.serializer = DummySerializer.DEFAULT;
-    }
-
-    protected Message(MessageSerializer serializer) {
-        this.serializer = serializer;
-    }
-
+public interface Message {
     /**
-     * @param payload Bitcoin protocol formatted byte array containing message content.
-     * @param serializer the serializer to use for this message.
-     * @throws ProtocolException
+     * Maximum size of a Bitcoin P2P Message (32 MB)
      */
-    protected Message(ByteBuffer payload, MessageSerializer serializer) throws ProtocolException {
-        this.serializer = serializer;
-
-        try {
-            parse(payload);
-        } catch(BufferUnderflowException e) {
-            throw new ProtocolException(e);
-        }
-    }
-
-    protected Message(ByteBuffer payload) throws ProtocolException {
-        this(payload, DummySerializer.DEFAULT);
-    }
-
-    // These methods handle the serialization/deserialization using the custom Bitcoin protocol.
-
-    protected abstract void parse(ByteBuffer payload) throws BufferUnderflowException, ProtocolException;
-
-    /**
-     * <p>Serialize this message to a byte array that conforms to the bitcoin wire protocol.</p>
-     *
-     * @return a byte array
-     */
-    public final byte[] bitcoinSerialize() {
-        // No cached array available so serialize parts by stream.
-        ByteArrayOutputStream stream = new ByteArrayOutputStream(100); // initial size just a guess
-        try {
-            bitcoinSerializeToStream(stream);
-        } catch (IOException e) {
-            // Cannot happen, we are serializing to a memory stream.
-        }
-        return stream.toByteArray();
-    }
-
-    /** @deprecated use {@link #bitcoinSerialize()} */
-    @Deprecated
-    public byte[] unsafeBitcoinSerialize() {
-        return bitcoinSerialize();
-    }
-
-    /**
-     * Serializes this message to the provided stream. If you just want the raw bytes use bitcoinSerialize().
-     */
-    protected void bitcoinSerializeToStream(OutputStream stream) throws IOException {
-        log.error("Error: {} class has not implemented bitcoinSerializeToStream method.  Generating message with no payload", getClass());
-    }
-
-    /** @deprecated use {@link Transaction#getTxId()}, {@link Block#getHash()}, {@link FilteredBlock#getHash()} or {@link TransactionOutPoint#hash()} */
-    @Deprecated
-    public Sha256Hash getHash() {
-        throw new UnsupportedOperationException();
-    }
+    int MAX_SIZE = 0x02000000;
 
     /**
      * Return the size of the serialized message. Note that if the message was deserialized from a payload, this
      * size can differ from the size of the original payload.
-     * @return size of the serialized message in bytes
+     *
+     * @return size of this object when serialized (in bytes)
      */
-    public int getMessageSize() {
-        return bitcoinSerialize().length;
-    }
+    int getMessageSize();
+
+    /**
+     * Serialize this message to a byte array that conforms to the Bitcoin wire protocol.
+     *
+     * @return serialized data in Bitcoin protocol format
+     */
+    byte[] bitcoinSerialize();
 }

core/src/main/java/org/bitcoinj/core/Ping.java

@@ -30,7 +30,7 @@ import java.util.Random;
  *
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class Ping extends Message {
+public class Ping extends BaseMessage {
     private long nonce;
 
     public Ping(ByteBuffer payload) throws ProtocolException {

core/src/main/java/org/bitcoinj/core/Pong.java

@@ -29,7 +29,7 @@ import java.nio.ByteBuffer;
  *
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class Pong extends Message {
+public class Pong extends BaseMessage {
     private long nonce;
 
     public Pong(ByteBuffer payload) throws ProtocolException {

core/src/main/java/org/bitcoinj/core/RejectMessage.java

@@ -35,7 +35,7 @@ import java.util.stream.Stream;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class RejectMessage extends Message {
+public class RejectMessage extends BaseMessage {
 
     private String message, reason;
     public enum RejectCode {

core/src/main/java/org/bitcoinj/core/Transaction.java

@@ -92,7 +92,7 @@ import static org.bitcoinj.base.internal.ByteUtils.writeInt64LE;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class Transaction extends Message {
+public class Transaction extends BaseMessage {
     private static final Comparator<Transaction> SORT_TX_BY_ID = Comparator.comparing(Transaction::getTxId);
 
     /**

core/src/main/java/org/bitcoinj/core/VersionMessage.java

@@ -48,7 +48,7 @@ import static org.bitcoinj.base.internal.Preconditions.check;
  * 
  * <p>Instances of this class are not safe for use by multiple threads.</p>
  */
-public class VersionMessage extends Message {
+public class VersionMessage extends BaseMessage {
 
     /** The version of this library release, as a string. */
     public static final String BITCOINJ_VERSION = "0.17-SNAPSHOT";

core/src/test/java/org/bitcoinj/core/BitcoinSerializerTest.java

@@ -233,7 +233,7 @@ public class BitcoinSerializerTest {
     public void testSerializeUnknownMessage() throws Exception {
         MessageSerializer serializer = MAINNET.getDefaultSerializer();
 
-        Message unknownMessage = new Message() {
+        Message unknownMessage = new BaseMessage() {
             @Override
             protected void parse(ByteBuffer payload) throws BufferUnderflowException, ProtocolException {
             }