PMessageOrBuilder.java

/*
 * Copyright 2015-2016 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.providence;

import net.morimekta.providence.descriptor.PField;
import net.morimekta.providence.descriptor.PMessageDescriptor;

import javax.annotation.Nonnull;

/**
 * Base class for all messages and message builders.
 */
public interface PMessageOrBuilder<Message extends PMessage<Message>>
        extends PValue<Message> {
    /**
     * @param key The key of the field.
     * @return Whether the field is present.
     */
    boolean has(int key);

    /**
     * @param key The key of the field.
     * @param <T> The return type.
     * @return The value of the field.
     */
    <T> T get(int key);

    /**
     * @param field The field.
     * @param <F> The message field type.
     * @return Whether the field is present.
     */
    default <F extends PField<Message>> boolean has(@Nonnull F field) {
        return has(field.getId());
    }

    /**
     * @param field The field.
     * @param <T> The return type.
     * @param <F> The message field type.
     * @return Whether the field is present.
     */
    default <T, F extends PField<Message>> T get(@Nonnull F field) {
        return get(field.getId());
    }

    /**
     * Cast the message or builder instance to it's instance, or build so
     * it becomes a new instance from the builder.
     *
     * @return The message instance.
     */
    @Nonnull
    @SuppressWarnings("unchecked")
    default Message toMessage() {
        if (this instanceof PMessageBuilder) {
            return ((PMessageBuilder<Message>) this).build();
        }
        return (Message) this;
    }

    /**
     * Cast the message or builder instance to it's builder or mutate the instance
     * so we have a fresh builder.
     *
     * @param <Builder> The builder type.
     * @return The builder instance.
     */
    @Nonnull
    @SuppressWarnings("unchecked")
    default <Builder extends PMessageBuilder<Message>>
    Builder toBuilder() {
        if (this instanceof PMessageBuilder) {
            return (Builder) this;
        }
        return (Builder) ((Message) this).mutate();
    }

    @Nonnull
    @Override
    PMessageDescriptor<Message> descriptor();
}