Make people aware of NULLs in the StreamSerializer class.

ProtocolLib/src/main/java/com/comphenix/protocol/utility/StreamSerializer.java

@@ -6,6 +6,9 @@ import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.lang.reflect.Method;
+
+import javax.annotation.Nonnull;
+
 import org.bukkit.inventory.ItemStack;
 import org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder;
 
@@ -28,10 +31,12 @@ public class StreamSerializer {
 	 * and {@link java.io.DataInputStream DataInputStream}. 
 	 * 
 	 * @param input - the target input stream.
-	 * @return The resulting item stack.
+	 * @return The resulting item stack, or NULL if the serialized item stack was NULL.
 	 * @throws IOException If the operation failed due to reflection or corrupt data.
 	 */
-	public ItemStack deserializeItemStack(DataInputStream input) throws IOException {
+	public ItemStack deserializeItemStack(@Nonnull DataInputStream input) throws IOException {
+		if (input == null)
+			throw new IllegalArgumentException("Input stream cannot be NULL.");
 		if (readItemMethod == null)
 			readItemMethod = FuzzyReflection.fromClass(MinecraftReflection.getPacketClass()).
 								getMethodByParameters("readPacket", 
@@ -51,10 +56,13 @@ public class StreamSerializer {
 	/**
 	 * Deserialize an item stack from a base-64 encoded string.
 	 * @param input - base-64 encoded string.
-	 * @return A deserialized item stack.
+	 * @return A deserialized item stack, or NULL if the serialized ItemStack was also NULL.
 	 * @throws IOException If the operation failed due to reflection or corrupt data.
 	 */
-	public ItemStack deserializeItemStack(String input) throws IOException {
+	public ItemStack deserializeItemStack(@Nonnull String input) throws IOException {
+		if (input == null)
+			throw new IllegalArgumentException("Input text cannot be NULL.");
+		
 		ByteArrayInputStream inputStream = new ByteArrayInputStream(Base64Coder.decodeLines(input));
 		
 		return deserializeItemStack(new DataInputStream(inputStream));
@@ -65,12 +73,18 @@ public class StreamSerializer {
 	 * <p>
 	 * To supply a byte array, wrap it in a {@link java.io.ByteArrayOutputStream ByteArrayOutputStream} 
 	 * and {@link java.io.DataOutputStream DataOutputStream}. 
+	 * <p>
+	 * Note: An ItemStack can be written to a stream even if it's NULL.
 	 * 
 	 * @param output - the target output stream.
-	 * @param stack - the item stack that will be written.
+	 * @param stack - the item stack that will be written, or NULL to represent air/nothing.
 	 * @throws IOException If the operation fails due to reflection problems.
 	 */
-	public void serializeItemStack(DataOutputStream output, ItemStack stack) throws IOException {
+	public void serializeItemStack(@Nonnull DataOutputStream output, ItemStack stack) throws IOException {
+		if (output == null)
+			throw new IllegalArgumentException("Output stream cannot be NULL.");
+		
+		// Get the NMS version of the ItemStack
 		Object nmsItem = MinecraftReflection.getMinecraftItemStack(stack);
 		
 		if (writeItemMethod == null)
@@ -87,7 +101,10 @@ public class StreamSerializer {
 	
 	/**
 	 * Serialize an item stack as a base-64 encoded string.
-	 * @param stack - the item stack to serialize.
+	 * <p>
+	 * Note: An ItemStack can be written to the serialized text even if it's NULL.
+	 * 
+	 * @param stack - the item stack to serialize, or NULL to represent air/nothing.
 	 * @return A base-64 representation of the given item stack.
 	 * @throws IOException If the operation fails due to reflection problems.
 	 */