/*
 * Copyright 2019, TeamDev. All rights reserved.
 *
 * Redistribution and use in source and/or binary forms, with or without
 * modification, must retain the above copyright notice and the following
 * disclaimer.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package io.spine.code.proto;

import com.google.protobuf.DescriptorProtos.FieldOptions;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.GeneratedMessage.GeneratedExtension;

import java.util.Optional;

/**
 * A Protobuf option that is applied to fields in Protobuf messages.
 *
 * @param <O>
 *         value of this option
 */
public class FieldOption<O> implements Option<O, FieldDescriptor> {

    private final GeneratedExtension<FieldOptions, O> extension;

    /**
     * Creates an instance with the
     * <a href="https://developers.google.com/protocol-buffers/docs/proto3#custom_options">Protobuf
     * extension</a>
     * that corresponds to this option.
     */
    protected FieldOption(GeneratedExtension<FieldOptions, O> extension) {
        this.extension = extension;
    }

    /** Obtains the Protobuf extension associated with the option. */
    protected GeneratedExtension<FieldOptions, O> extension() {
        return extension;
    }

    @Override
    public Optional<O> valueFrom(FieldDescriptor object) {
        FieldOptions options = object.getOptions();
        boolean explicitlySet = options.hasExtension(extension);
        O value = options.getExtension(extension);
        return explicitlySet
               ? Optional.of(value)
               : Optional.empty();
    }
}

@@ -1330,17 +1330,17 @@
 @param %3C
-O
+F
 %3E%0A *    
@@ -1394,17 +1394,17 @@
 dOption%3C
-O
+F
 %3E implem
@@ -1415,17 +1415,17 @@
  Option%3C
-O
+F
 , FieldD
@@ -1481,33 +1481,33 @@
 n%3CFieldOptions, 
-O
+F
 %3E extension;%0A%0A  
@@ -1768,33 +1768,33 @@
 n%3CFieldOptions, 
-O
+F
 %3E extension) %7B%0A 
@@ -1952,17 +1952,17 @@
 ptions, 
-O
+F
 %3E extens
@@ -2036,17 +2036,17 @@
 ptional%3C
-O
+F
 %3E valueF
@@ -2200,17 +2200,17 @@
         
-O
+F
  value =

Rename type parameter.