[#165] fix java code warnings and add nullness annotations

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/Utils.java

@@ -1,5 +1,6 @@
 package net.zscript.javaclient.commandbuilder;
 
+import javax.annotation.Nonnull;
 import java.nio.charset.StandardCharsets;
 import java.util.BitSet;
 import java.util.EnumSet;
@@ -23,6 +24,7 @@ public class Utils {
      * @param <E>       the enum type itself
      * @return a Set containing the corresponding values defined in the enum
      */
+    @Nonnull
     public static <E extends Enum<E>> EnumSet<E> bitsetToEnumSet(int bitFields, Class<E> enumClass) {
         final E[] enumValues = enumClass.getEnumConstants();
         return BitSet.valueOf(new long[] { bitFields }).stream()
@@ -51,6 +53,7 @@ public static <E extends Enum<E>> int checkInEnumRange(int value, Class<E> enumC
         return value;
     }
 
+    @Nonnull
     public static byte[] formatField(byte f, int value) {
         if (value >= 0x10000 || value < 0) {
             throw new IllegalStateException("Command fields must be uint16s: " + value);

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/AndSequenceNode.java

@@ -1,7 +1,5 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/CommandSequenceNode.java

@@ -1,5 +1,6 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
+import javax.annotation.Nonnull;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
@@ -113,6 +114,7 @@ CommandSequenceNode optimize() {
 
     public abstract List<CommandSequenceNode> getChildren();
 
+    @Nonnull
     @Override
     public Iterator<ZscriptCommandNode<?>> iterator() {
         if (this instanceof ZscriptCommandNode) {

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/OrSequenceNode.java

@@ -1,11 +1,6 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
 import java.util.List;
-import java.util.stream.Collectors;
-
-import net.zscript.model.components.Zchars;
 
 public class OrSequenceNode extends CommandSequenceNode {
     final CommandSequenceNode before;
@@ -27,7 +22,7 @@ protected boolean canFail() {
     boolean isCommand() {
         return false;
     }
-
+ 
     @Override
     CommandSequenceNode optimize() {
         if (!before.canFail()) {

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/ResponseCaptor.java

@@ -1,11 +1,13 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
-import java.util.NoSuchElementException;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 import net.zscript.javaclient.commandbuilder.Respondable;
 import net.zscript.javaclient.commandbuilder.ZscriptResponse;
 
 public class ResponseCaptor<T extends ZscriptResponse> {
+    @Nonnull
     public static <T extends ZscriptResponse> ResponseCaptor<T> create() {
         return new ResponseCaptor<>();
     }
@@ -19,6 +21,7 @@ public void setSource(Respondable<T> source) {
         this.source = source;
     }
 
+    @Nullable
     public Respondable<T> getSource() {
         return source;
     }

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/ZscriptCommandBuilder.java

@@ -1,5 +1,6 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
+import javax.annotation.Nonnull;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.BitSet;
@@ -95,6 +96,7 @@ protected final void setRequiredFields(byte[] keys) {
         }
     }
 
+    @Nonnull
     public ZscriptCommandBuilder<T> capture(ResponseCaptor<T> captor) {
         this.captor = captor;
         return this;
@@ -129,5 +131,6 @@ protected void failIfInvalid() {
      * @return the command that has been built
      * @throws ZscriptMissingFieldException if builder doesn't yet pass validation
      */
+    @Nonnull
     public abstract ZscriptCommandNode<T> build();
 }

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/ZscriptCommandNode.java

@@ -1,5 +1,7 @@
 package net.zscript.javaclient.commandbuilder.commandnodes;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -29,7 +31,7 @@ protected ZscriptCommandNode() {
         this(null, Collections.emptyList(), Collections.emptyMap());
     }
 
-    protected ZscriptCommandNode(ResponseCaptor<T> captor, List<BigField> bigFields, Map<Byte, Integer> fields) {
+    protected ZscriptCommandNode(@Nullable ResponseCaptor<T> captor, List<BigField> bigFields, Map<Byte, Integer> fields) {
         this.captor = captor;
         this.bigFields = bigFields;
         this.fields = fields;
@@ -38,23 +40,29 @@ protected ZscriptCommandNode(ResponseCaptor<T> captor, List<BigField> bigFields,
         }
     }
 
+    @Nullable
     public ResponseCaptor<T> getCaptor() {
         return captor;
     }
 
+    @Nonnull
     public abstract T parseResponse(ZscriptExpression response);
 
+    @Nonnull
     public abstract Class<T> getResponseType();
 
+    @Nonnull
     public List<CommandSequenceNode> getChildren() {
         return Collections.emptyList();
     }
 
+    @Nonnull
     public ZscriptFieldSet asFieldSet() {
         return ZscriptFieldSet.fromMap(bigFields.stream().map(BigField::getData).collect(Collectors.toList()),
                 bigFields.stream().map(BigField::isString).collect(Collectors.toList()), fields);
     }
 
+    @Nonnull
     @Override
     public String asString() {
         ByteString.ByteStringBuilder b = ByteString.builder();

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/commandnodes/package-info.java

@@ -0,0 +1,4 @@
+@ParametersAreNonnullByDefault
+package net.zscript.javaclient.commandbuilder.commandnodes;
+
+import javax.annotation.ParametersAreNonnullByDefault;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/defaultCommands/AbortCommandNode.java

@@ -1,5 +1,6 @@
 package net.zscript.javaclient.commandbuilder.defaultCommands;
 
+import javax.annotation.Nonnull;
 import java.util.Collections;
 import java.util.Map;
 
@@ -60,11 +61,13 @@ protected boolean canFail() {
         return false;
     }
 
+    @Nonnull
     @Override
     public DefaultResponse parseResponse(ZscriptExpression response) {
         return new DefaultResponse(response);
     }
 
+    @Nonnull
     @Override
     public Class<DefaultResponse> getResponseType() {
         return DefaultResponse.class;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/defaultCommands/BlankCommandNode.java

@@ -1,5 +1,7 @@
 package net.zscript.javaclient.commandbuilder.defaultCommands;
 
+import javax.annotation.Nonnull;
+
 import net.zscript.javaclient.commandbuilder.commandnodes.CommandSequenceNode;
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandNode;
 import net.zscript.tokenizer.ZscriptExpression;
@@ -51,11 +53,13 @@ protected boolean canFail() {
         return false;
     }
 
+    @Nonnull
     @Override
     public DefaultResponse parseResponse(ZscriptExpression response) {
         return new DefaultResponse(response);
     }
 
+    @Nonnull
     @Override
     public Class<DefaultResponse> getResponseType() {
         return DefaultResponse.class;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/defaultCommands/FailureCommandNode.java

@@ -1,5 +1,6 @@
 package net.zscript.javaclient.commandbuilder.defaultCommands;
 
+import javax.annotation.Nonnull;
 import java.util.Collections;
 import java.util.Map;
 
@@ -55,11 +56,13 @@ public CommandSequenceNode onFail(CommandSequenceNode next) {
         return next;
     }
 
+    @Nonnull
     @Override
     public DefaultResponse parseResponse(ZscriptExpression response) {
         return new DefaultResponse(response);
     }
 
+    @Nonnull
     @Override
     public Class<DefaultResponse> getResponseType() {
         return DefaultResponse.class;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/defaultCommands/GenericCommandBuilder.java

@@ -1,5 +1,7 @@
 package net.zscript.javaclient.commandbuilder.defaultCommands;
 
+import javax.annotation.Nonnull;
+
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandBuilder;
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandNode;
 import net.zscript.tokenizer.ZscriptExpression;
@@ -37,14 +39,17 @@ public ZscriptCommandBuilder<DefaultResponse> addBigField(String data) {
         return super.addBigField(data);
     }
 
+    @Nonnull
     @Override
     public ZscriptCommandNode<DefaultResponse> build() {
-        return new ZscriptCommandNode<DefaultResponse>() {
+        return new ZscriptCommandNode<>() {
+            @Nonnull
             @Override
             public DefaultResponse parseResponse(ZscriptExpression response) {
                 return new DefaultResponse(response);
             }
 
+            @Nonnull
             @Override
             public Class<DefaultResponse> getResponseType() {
                 return DefaultResponse.class;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/defaultCommands/package-info.java

@@ -0,0 +1,4 @@
+@ParametersAreNonnullByDefault
+package net.zscript.javaclient.commandbuilder.defaultCommands;
+
+import javax.annotation.ParametersAreNonnullByDefault;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/notifications/NotificationHandle.java

@@ -1,11 +1,14 @@
 package net.zscript.javaclient.commandbuilder.notifications;
 
+import javax.annotation.Nonnull;
 import java.util.List;
 
 import net.zscript.javaclient.commandbuilder.ZscriptResponse;
 
 public abstract class NotificationHandle {
+    @Nonnull
     public abstract <T extends ZscriptResponse> NotificationSection<T> getSection(NotificationSectionId<T> response);
 
+    @Nonnull
     public abstract List<NotificationSection<?>> getSections();
 }

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/notifications/package-info.java

@@ -0,0 +1,4 @@
+@ParametersAreNonnullByDefault
+package net.zscript.javaclient.commandbuilder.notifications;
+
+import javax.annotation.ParametersAreNonnullByDefault;

clients/java-client-lib/client-command-api/src/main/java/net/zscript/javaclient/commandbuilder/package-info.java

@@ -0,0 +1,4 @@
+@ParametersAreNonnullByDefault
+package net.zscript.javaclient.commandbuilder;
+
+import javax.annotation.ParametersAreNonnullByDefault;

clients/java-client-lib/client-command-api/src/test/java/net/zscript/javaclient/commandbuilder/DemoActivateCommand.java

@@ -1,5 +1,7 @@
 package net.zscript.javaclient.commandbuilder;
 
+import javax.annotation.Nonnull;
+
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandBuilder;
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandNode;
 import net.zscript.tokenizer.ZscriptExpression;
@@ -14,11 +16,13 @@ public static DemoActivateCommandBuilder builder() {
         return new DemoActivateCommandBuilder();
     }
 
+    @Nonnull
     @Override
-    public DemoActivateCommandResponse parseResponse(ZscriptExpression resp) {
+    public DemoActivateCommandResponse parseResponse(@Nonnull ZscriptExpression resp) {
         return new DemoActivateCommandResponse(resp, new byte[] {}, resp.getField('A').orElse(0) == 1);
     }
 
+    @Nonnull
     @Override
     public Class<DemoActivateCommandResponse> getResponseType() {
         return DemoActivateCommandResponse.class;
@@ -35,6 +39,7 @@ public DemoActivateCommandBuilder() {
             setField('Z', 2);
         }
 
+        @Nonnull
         @Override
         public DemoActivateCommand build() {
             return new DemoActivateCommand(this);

clients/java-client-lib/client-command-api/src/test/java/net/zscript/javaclient/commandbuilder/commandNodes/DemoCapabilitiesCommandBuilder.java

@@ -1,5 +1,7 @@
 package net.zscript.javaclient.commandbuilder.commandNodes;
 
+import javax.annotation.Nonnull;
+
 import static java.nio.charset.StandardCharsets.ISO_8859_1;
 
 import net.zscript.javaclient.commandbuilder.commandnodes.ZscriptCommandBuilder;
@@ -26,22 +28,23 @@ public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> setField(char key,
         return super.setField(key, value);
     }
 
-    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(byte[] data) {
+    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(@Nonnull byte[] data) {
         return super.addBigField(data);
     }
 
-    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(byte[] data, boolean asString) {
+    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(@Nonnull byte[] data, boolean asString) {
         return super.addBigField(data, asString);
     }
 
-    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigFieldAsSmallest(byte[] data) {
+    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigFieldAsSmallest(@Nonnull byte[] data) {
         return super.addBigField(data);
     }
 
-    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(String data) {
+    public ZscriptCommandBuilder<DemoCapabilitiesCommandResponse> addBigField(@Nonnull String data) {
         return super.addBigField(data);
     }
 
+    @Nonnull
     @Override
     public ZscriptCommandNode<DemoCapabilitiesCommandResponse> build() {
         return new DemoCapabilities(this);
@@ -57,11 +60,13 @@ public static DemoCapabilitiesCommandBuilder builder() {
         return new DemoCapabilitiesCommandBuilder();
     }
 
+    @Nonnull
     @Override
-    public DemoCapabilitiesCommandResponse parseResponse(ZscriptExpression resp) {
+    public DemoCapabilitiesCommandResponse parseResponse(@Nonnull ZscriptExpression resp) {
         return new DemoCapabilitiesCommandResponse(resp, new byte[] {}, resp.getField('V').getAsInt(), new String(resp.getBigFieldData(), ISO_8859_1));
     }
 
+    @Nonnull
     @Override
     public Class<DemoCapabilitiesCommandResponse> getResponseType() {
         return DemoCapabilitiesCommandResponse.class;