001/*
002 * Copyright 2022-2026 Revetware LLC.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.soklet;
018
019import org.jspecify.annotations.NonNull;
020import org.jspecify.annotations.Nullable;
021
022import javax.annotation.concurrent.ThreadSafe;
023
024import static java.util.Objects.requireNonNull;
025
026/**
027 * Converts app-owned structured content objects into {@link McpValue}.
028 *
029 * @author <a href="https://www.revetkn.com">Mark Allen</a>
030 */
031@ThreadSafe
032public interface McpResponseMarshaler {
033        /**
034         * Converts app-owned structured content into an {@link McpValue} tree that Soklet can embed into the MCP response.
035         *
036         * @param value the app-owned structured content value, possibly {@code null}
037         * @param context the marshaling context for the current tool call
038         * @return the marshaled MCP value
039         */
040        @NonNull
041        McpValue marshalStructuredContent(@Nullable Object value,
042                                                                                                                                                @NonNull McpStructuredContentContext context);
043
044        /**
045         * Acquires Soklet's default structured-content marshaler.
046         *
047         * @return the default marshaler instance
048         */
049        @NonNull
050        static McpResponseMarshaler defaultInstance() {
051                return DefaultMcpResponseMarshaler.INSTANCE;
052        }
053}
054
055enum DefaultMcpResponseMarshaler implements McpResponseMarshaler {
056        INSTANCE;
057
058        @NonNull
059        @Override
060        public McpValue marshalStructuredContent(@Nullable Object value,
061                                                                                                                                                                         @NonNull McpStructuredContentContext context) {
062                requireNonNull(context);
063
064                if (value == null)
065                        return McpNull.INSTANCE;
066
067                if (value instanceof McpValue mcpValue)
068                        return mcpValue;
069
070                throw new IllegalArgumentException("Structured content value '%s' is not an McpValue. Supply a custom McpResponseMarshaler to handle arbitrary objects.".formatted(value.getClass().getName()));
071        }
072}