Generate Java validation code at compile time

base-validating-builders/build.gradle

@@ -63,6 +63,10 @@ apply plugin: 'com.google.protobuf'
 apply plugin: 'io.spine.tools.spine-model-compiler'
 apply plugin: 'idea'
 
+modelCompiler {
+    generateValidation = true
+}
+
 repositories {
     // This defines the `libs` directory of upstream projects as a local repository.
     // See `dependencies` section below for definition of the dependency on the JAR produced by 

base/src/main/java/io/spine/code/java/ClassName.java

@@ -34,8 +34,8 @@
 
 import java.util.Deque;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.collect.Lists.newLinkedList;
 import static io.spine.code.java.SimpleClassName.OR_BUILDER_SUFFIX;
 import static io.spine.util.Preconditions2.checkNotEmptyOrBlank;
@@ -313,11 +313,16 @@ private static String afterDot(String fullName) {
      * Obtains the name of the package of this class.
      */
     public PackageName packageName() {
+        int packageEndIndex = packageEndIndex();
+        String result = value().substring(0, packageEndIndex);
+        return PackageName.of(result);
+    }
+
+    private int packageEndIndex() {
         String fullName = value();
         int lastDotIndex = fullName.lastIndexOf(DOT_SEPARATOR);
-        checkArgument(lastDotIndex > 0, "%s should be qualified.", fullName);
-        String result = fullName.substring(0, lastDotIndex);
-        return PackageName.of(result);
+        checkState(lastDotIndex > 0, "%s should be qualified.", fullName);
+        return lastDotIndex;
     }
 
     /**

base/src/main/java/io/spine/code/proto/FieldContext.java

@@ -96,6 +96,17 @@ public FieldContext forChild(FieldDescriptor child) {
         return new FieldContext(this, child);
     }
 
+    /**
+     * Obtains {@code FieldContext} for the specified child.
+     *
+     * @param child
+     *         the child declaration
+     * @return the child declaration context
+     */
+    public FieldContext forChild(FieldDeclaration child) {
+        return forChild(child.descriptor());
+    }
+
     /**
      * Obtains target of this context.
      *
@@ -105,6 +116,16 @@ public FieldDescriptor target() {
         return checkNotNull(target, "Empty context cannot have a target.");
     }
 
+    /**
+     * Obtains target of this context as a {@link FieldDeclaration}.
+     *
+     * @return the target declaration
+     */
+    public FieldDeclaration targetDeclaration() {
+        FieldDescriptor target = target();
+        return new FieldDeclaration(target);
+    }
+
     private Optional<FieldDescriptor> targetParent() {
         return parent == null ? Optional.empty() : Optional.ofNullable(parent.target);
     }
@@ -164,12 +185,16 @@ public boolean equals(Object o) {
             return false;
         }
         FieldContext context = (FieldContext) o;
-        return Objects.equals(target, context.target) &&
-                Objects.equals(parent, context.parent);
+        return Objects.equals(targetNameOrEmpty(), context.targetNameOrEmpty())
+                && Objects.equals(parent, context.parent);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(target, parent);
+        return Objects.hash(targetNameOrEmpty(), parent);
+    }
+
+    private String targetNameOrEmpty() {
+        return target != null ? target.getFullName() : "";
     }
 }

base/src/main/java/io/spine/code/proto/FieldDeclaration.java

@@ -22,6 +22,7 @@
 
 import com.google.common.base.Objects;
 import com.google.errorprone.annotations.Immutable;
+import com.google.protobuf.Any;
 import com.google.protobuf.DescriptorProtos.FieldDescriptorProto;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor.JavaType;
@@ -128,21 +129,35 @@ private boolean sameMessageType(Message msg) {
     }
 
     /**
-     * Obtains fully-qualified name of the Java class that corresponds to the declared type
-     * of the field.
+     * Obtains fully-qualified canonical name of the Java class that corresponds to the declared
+     * type of the field.
+     *
+     * <p>If the field is {@code repeated}, obtains the name of the elements.
+     *
+     * <p>If the field is a {@code map}, obtains the name of the values.
      */
     public String javaTypeName() {
+        return isMap()
+               ? javaTypeName(valueDeclaration().field)
+               : javaTypeName(this.field);
+    }
+
+    private static String javaTypeName(FieldDescriptor field) {
         FieldDescriptor.Type fieldType = field.getType();
         if (fieldType == MESSAGE) {
-            return messageClassName();
+            MessageType messageType =
+                    new MessageType(field.getMessageType());
+            return messageType.javaClassName()
+                              .canonicalName();
         }
 
         if (fieldType == ENUM) {
-            return enumClassName();
+            EnumType enumType = EnumType.create(field.getEnumType());
+            return enumType.javaClassName()
+                           .canonicalName();
         }
 
-        return ScalarType.javaTypeName(field.toProto()
-                                            .getType());
+        return ScalarType.javaTypeName(field.toProto().getType());
     }
 
     private String messageClassName() {
@@ -161,11 +176,6 @@ private String messageClassName() {
         }
     }
 
-    private String enumClassName() {
-        EnumType enumType = EnumType.create(field.getEnumType());
-        return enumType.javaClassName().value();
-    }
-
     /**
      * Determines whether the field is an entity ID.
      *
@@ -177,21 +187,28 @@ private String enumClassName() {
      * </ul>
      *
      * @return {@code true} if the field is an entity ID, {@code false} otherwise
+     * @see #isId()
      */
     public boolean isEntityId() {
         return isFirstField() && isEntityField() && isNotCollection();
     }
 
     /**
-     * Determines whether the field is a command ID.
+     * Determines whether the field is an ID.
      *
-     * <p>A command ID is the first field of a message declared in a
-     * {@link MessageFile#COMMANDS commands file}.
+     * <p>An ID satisfies the following conditions:
+     * <ul>
+     *     <li>Declared as the first field.
+     *     <li>Declared inside an {@linkplain EntityOption#getKind() entity state message} or
+     *         a {@linkplain io.spine.base.CommandMessage command message};
+     *     <li>Is not a map or a repeated field.
+     * </ul>
      *
-     * @return {@code true} if the field is a command ID, {@code false} otherwise
+     * @return {@code true} if the field is an entity ID, {@code false} otherwise
      */
-    public boolean isCommandId() {
-        return isFirstField() && isCommandsFile();
+    public boolean isId() {
+        boolean fieldMatches = isFirstField() && isNotCollection();
+        return fieldMatches && (isCommandsFile() || isEntityField());
     }
 
     /**
@@ -209,16 +226,28 @@ public boolean isString() {
     }
 
     /**
-     * Tells if the field is of enum type.
+     * Tells if the field is of an enum type.
      */
     public boolean isEnum() {
         return field.getType() == ENUM;
     }
 
+    /**
+     * Tells if the field is of a message type.
+     */
     public boolean isMessage() {
         return field.getType() == MESSAGE;
     }
 
+    /**
+     * Tells if the field is of type {@code google.protobuf.Any}.
+     */
+    public boolean isAny() {
+        return isMessage() && field.getMessageType()
+                                   .getFullName()
+                                   .equals(Any.getDescriptor().getFullName());
+    }
+
     /**
      * Determines whether the declaration is a singular value.
      *
@@ -356,4 +385,14 @@ public boolean equals(Object o) {
     public int hashCode() {
         return Objects.hashCode(declaringMessage, field.getFullName());
     }
+
+    /**
+     * Obtains qualified name of this field.
+     *
+     * <p>Example: {@code spine.net.Uri.protocol}.
+     */
+    @Override
+    public String toString() {
+        return field.getFullName();
+    }
 }

base/src/main/java/io/spine/code/proto/Option.java

@@ -44,8 +44,19 @@ public interface Option<@ImmutableTypeParameter T,
      * Obtains the value of this option for the specified object that holds it.
      *
      * @param object
-     *         holder of the option
+     *         the option holder
      * @return value of this option
      */
     Optional<T> valueFrom(K object);
+
+    /**
+     * Checks if the option is declared on the given holder.
+     *
+     * @param object
+     *         the option holder
+     * @return {@code true} if the option is declared and is non-default, {@code false} otherwise
+     */
+    default boolean valuePresent(K object) {
+        return valueFrom(object).isPresent();
+    }
 }

base/src/main/java/io/spine/code/proto/OptionExtensionRegistry.java

@@ -46,8 +46,7 @@ private OptionExtensionRegistry() {
     }
 
     /**
-     * Obtains the {@link ExtensionRegistry} with all the {@code
-     * spine/options.proto} extensions.
+     * Obtains the {@link ExtensionRegistry} with all the {@code spine/options.proto} extensions.
      */
     public static ExtensionRegistry instance() {
         return EXTENSIONS;

base/src/main/java/io/spine/validate/option/Constraint.java → base/src/main/java/io/spine/protobuf/MessageWithConstraints.java

@@ -18,33 +18,27 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package io.spine.validate.option;
+package io.spine.protobuf;
 
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.Immutable;
-import com.google.errorprone.annotations.ImmutableTypeParameter;
+import com.google.protobuf.Message;
+import io.spine.annotation.Beta;
 import io.spine.validate.ConstraintViolation;
 
 /**
- * A rule that limits the set of possible values for {@code T} and produces
- * {@code ConstraintViolations} upon finding values of {@code T} which do not fit into the
- * set limits.
+ * A message with validation constraints.
  *
- * @param <T>
- *         a type of values that this constraint is applicable to
+ * <p>Please see {@code spine/options.proto} for the definitions of validation options.
  */
+@Beta
 @Immutable
-public interface Constraint<@ImmutableTypeParameter T> {
+public interface MessageWithConstraints extends Message {
 
     /**
-     * Checks the specified value against this constraint.
+     * Validates this message according to the rules in the Protobuf definition.
      *
-     * <p>If the value has breaks the rules imposed by this constraint, {@code ConstraintViolations}
-     * are produced and returned.
-     *
-     * @param value
-     *         value that is being checked against this constraint
-     * @return violations of this constraint
+     * @return a list of {@code ConstraintViolation}s or an empty list if the message is valid
      */
-    ImmutableList<ConstraintViolation> check(T value);
+    ImmutableList<ConstraintViolation> validate();
 }

base/src/main/java/io/spine/protobuf/Messages.java

@@ -25,6 +25,7 @@
 import com.google.protobuf.Any;
 import com.google.protobuf.Message;
 import com.google.protobuf.MessageLite;
+import com.google.protobuf.ProtocolMessageEnum;
 import io.spine.annotation.Internal;
 
 import java.lang.reflect.InvocationTargetException;
@@ -137,6 +138,30 @@ public static boolean isNotDefault(Message object) {
         return result;
     }
 
+    /**
+     * Verifies if the passed Protobuf enum element is the enum's default state.
+     *
+     * @param messageEnum
+     *         the enum element to inspect
+     * @return {@code true} if the passed enum is default, {@code false} otherwise
+     */
+    public static boolean isDefault(ProtocolMessageEnum messageEnum) {
+        checkNotNull(messageEnum);
+        return messageEnum.getNumber() == 0;
+    }
+
+    /**
+     * Verifies if the passed Protobuf enum element is NOT the enum's default state.
+     *
+     * @param messageEnum
+     *         the enum element to inspect
+     * @return {@code false} if the passed enum is default, {@code true} otherwise
+     */
+    public static boolean isNotDefault(ProtocolMessageEnum messageEnum) {
+        checkNotNull(messageEnum);
+        return !isDefault(messageEnum);
+    }
+
     /**
      * The loader of the cache of default instances per {@link Message} class.
      *

base/src/main/java/io/spine/protobuf/TypeConverter.java

@@ -295,7 +295,6 @@ protected Message toMessage(Message input) {
      * best-performant solution among options, such as {@link Class#getCanonicalName()
      * Class.getCanonicalName()}.
      */
-    @SuppressWarnings("OverlyCoupledClass")     // OK, as references a lot of type for casting.
     private static final class PrimitiveTypeCaster<M extends Message, T>
             extends MessageCaster<M, T> {
 
@@ -325,7 +324,8 @@ private static final class PrimitiveTypeCaster<M extends Message, T>
         @Override
         protected T toObject(M input) {
             Class<?> boxedType = input.getClass();
-            @SuppressWarnings("unchecked") Converter<M, T> typeUnpacker =
+            @SuppressWarnings("unchecked")
+            Converter<M, T> typeUnpacker =
                     (Converter<M, T>) PROTO_WRAPPER_TO_HANDLER.get(boxedType);
             checkArgument(typeUnpacker != null,
                           "Could not find a primitive type for %s.",
@@ -337,7 +337,8 @@ protected T toObject(M input) {
         @Override
         protected M toMessage(T input) {
             Class<?> cls = input.getClass();
-            @SuppressWarnings("unchecked") Converter<M, T> converter =
+            @SuppressWarnings("unchecked")
+            Converter<M, T> converter =
                     (Converter<M, T>) PRIMITIVE_TO_HANDLER.get(cls);
             checkArgument(converter != null,
                           "Could not find a wrapper type for %s.",

base/src/main/java/io/spine/type/KnownTypes.java

@@ -193,14 +193,14 @@ public boolean contains(TypeUrl typeUrl) {
         return type;
     }
 
-    private Type get(TypeName name) throws UnknownTypeException {
-        Type result = typeSet.find(name)
-                             .orElseThrow(() -> new UnknownTypeException(name.value()));
+    private Type<?, ?> get(TypeName name) throws UnknownTypeException {
+        Type<?, ?> result = typeSet.find(name)
+                                   .orElseThrow(() -> new UnknownTypeException(name.value()));
         return result;
     }
 
     private ClassName get(TypeUrl typeUrl) {
-        Type type = get(typeUrl.toTypeName());
+        Type<?, ?> type = get(typeUrl.toTypeName());
         ClassName result = type.javaClassName();
         return result;
     }