FieldUtil.java
- /*
- * Copyright 2020 Providence Authors
- *
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you 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 net.morimekta.proto.utils;
- import com.google.protobuf.ByteString;
- import com.google.protobuf.Descriptors;
- import net.morimekta.collect.SetBuilder;
- import net.morimekta.collect.UnmodifiableList;
- import net.morimekta.collect.UnmodifiableMap;
- import net.morimekta.collect.UnmodifiableSet;
- import net.morimekta.proto.ProtoEnum;
- import net.morimekta.proto.ProtoMessage;
- import java.util.ArrayList;
- import java.util.List;
- import java.util.Optional;
- import java.util.Set;
- import java.util.stream.Collectors;
- import static java.util.Objects.requireNonNull;
- import static net.morimekta.proto.utils.ValueUtil.toJavaValue;
- /**
- * Utilities regarding handling fields and field types.
- */
- public final class FieldUtil {
- /**
- * @param field A map type field descriptor.
- * @return The key field type for the map.
- */
- public static Descriptors.FieldDescriptor getMapKeyDescriptor(Descriptors.FieldDescriptor field) {
- requireNonNull(field, "field == null");
- if (!field.isMapField()) {
- throw new IllegalArgumentException(
- "Not a map field: " + field.getFullName());
- }
- return requireNonNull(field.getMessageType().findFieldByNumber(1), "keyDescriptor == null");
- }
- /**
- * @param field A map type field descriptor.
- * @return The value field type for the map.
- */
- public static Descriptors.FieldDescriptor getMapValueDescriptor(Descriptors.FieldDescriptor field) {
- requireNonNull(field, "field == null");
- if (!field.isMapField()) {
- throw new IllegalArgumentException(
- "Not a map field: " + field.getFullName());
- }
- return requireNonNull(field.getMessageType().findFieldByNumber(2), "valueDescriptor == null");
- }
- /**
- * @param field A field descriptor.
- * @return The default value for the type for the field.
- */
- public static Object getDefaultTypeValue(Descriptors.FieldDescriptor field) {
- requireNonNull(field, "field == null");
- if (field.isRepeated()) {
- if (field.isMapField()) {
- return UnmodifiableMap.mapOf();
- }
- return UnmodifiableList.listOf();
- } else {
- switch (field.getType().getJavaType()) {
- case MESSAGE: {
- return ProtoMessage.getDefaultInstance(field.getMessageType());
- }
- case ENUM: {
- return ProtoEnum.getEnumDescriptor(field.getEnumType())
- .getDefaultValue()
- .orElse(null);
- }
- case STRING:
- return "";
- case INT:
- return 0;
- case LONG:
- return 0L;
- case FLOAT:
- return 0.0F;
- case DOUBLE:
- return 0.0D;
- case BOOLEAN:
- return Boolean.FALSE;
- case BYTE_STRING:
- return ByteString.EMPTY;
- default:
- // not testable, should be impossible to happen.
- return null;
- }
- }
- }
- /**
- * @param field A field descriptor.
- * @return The default value for the field.
- */
- public static Object getDefaultFieldValue(Descriptors.FieldDescriptor field) {
- if (field.getJavaType() == Descriptors.FieldDescriptor.JavaType.MESSAGE) {
- return getDefaultTypeValue(field);
- } else {
- return Optional.ofNullable(toJavaValue(field, field.getDefaultValue()))
- .orElseGet(() -> getDefaultTypeValue(field));
- }
- }
- /**
- * Convert a key path to a list of consecutive fields for recursive lookup.
- *
- * @param rootDescriptor The root message descriptor.
- * @param path The '.' joined field name key.
- * @return Array of fields.
- */
- public static List<Descriptors.FieldDescriptor> fieldPathToFields(
- Descriptors.Descriptor rootDescriptor,
- String path) {
- requireNonNull(rootDescriptor, "rootDescriptor == null");
- requireNonNull(path, "path == null");
- if (path.isEmpty()) {
- throw new IllegalArgumentException("Empty path");
- }
- Descriptors.Descriptor descriptor = rootDescriptor;
- ArrayList<Descriptors.FieldDescriptor> fields = new ArrayList<>();
- String[] parts = path.split("\\.", Byte.MAX_VALUE);
- for (int i = 0; i < (parts.length - 1); ++i) {
- String name = parts[i];
- if (name.isEmpty()) {
- throw new IllegalArgumentException("Empty field name in '" + path + "'");
- }
- Descriptors.FieldDescriptor field = descriptor.findFieldByName(name);
- if (field == null) {
- throw new IllegalArgumentException(
- "Message " + descriptor.getFullName() + " has no field named " + name);
- }
- if (field.isMapField()) {
- var valueField = FieldUtil.getMapValueDescriptor(field);
- if (valueField.getType() != Descriptors.FieldDescriptor.Type.MESSAGE) {
- throw new IllegalArgumentException(
- "Intermediate map field '" + field.getFullName() + "' does not have message value type");
- }
- fields.add(field);
- descriptor = valueField.getMessageType();
- } else {
- if (field.getType() != Descriptors.FieldDescriptor.Type.MESSAGE) {
- throw new IllegalArgumentException(
- "Intermediate field '" + field.getFullName() + "' is not a message");
- }
- fields.add(field);
- descriptor = field.getMessageType();
- }
- }
- String name = parts[parts.length - 1];
- if (name.isEmpty()) {
- throw new IllegalArgumentException("Empty field name in '" + path + "'");
- }
- Descriptors.FieldDescriptor field = descriptor.findFieldByName(name);
- if (field == null) {
- throw new IllegalArgumentException(
- "Message " + descriptor.getFullName() + " has no field named " + name);
- }
- fields.add(field);
- return fields;
- }
- /**
- * Append field to the given path.
- *
- * @param fields Fields to make key path of.
- * @return The new appended key path.
- */
- public static String fieldPath(List<Descriptors.FieldDescriptor> fields) {
- requireNonNull(fields, "fields == null");
- if (fields.isEmpty()) {
- throw new IllegalArgumentException("No field arguments");
- }
- return fields.stream().map(Descriptors.FieldDescriptor::getName).collect(Collectors.joining("."));
- }
- /**
- * Append field to the given path.
- *
- * @param path The path to be appended to.
- * @param field The field who's name should be appended.
- * @return The new appended key path.
- */
- public static String fieldPathAppend(
- String path,
- Descriptors.FieldDescriptor field) {
- if (path == null || path.isEmpty()) {
- return field.getName();
- }
- return path + "." + field.getName();
- }
- /**
- * Filter a set of field descriptor paths to only contain the continuations
- * of paths starting with the given field.
- *
- * @param fieldDesc The set of field descriptor paths.
- * @param fieldsUnder The field to get paths under.
- * @return The filtered set of field paths.
- */
- public static Set<String> filterFields(Set<String> fieldDesc, Descriptors.FieldDescriptor fieldsUnder) {
- // extensions are not covered by this, so an extension will have no
- // fields undet it.
- if (fieldsUnder.isExtension()) {
- return Set.of();
- }
- SetBuilder<String> out = UnmodifiableSet.newBuilder();
- var subPathPrefix = fieldsUnder.getName() + ".";
- for (var fd : fieldDesc) {
- if (fd.startsWith(subPathPrefix)) {
- out.add(fd.substring(subPathPrefix.length()));
- }
- }
- return out.build();
- }
- }