Design Document - Part II API

Purpose

This Design Document gives the complete design of the software implementation. This information should be in structured comments (e.g. Javadoc) in the source files. We encourage the use of a documentation generation tool to generate a draft of your API that you can augment to include the following details.

Requirements

In addition to the general documentation requirements the Design Document - Part II API will contain:

General review of the software architecture for each module specified in Design Document - Part I Architecture. Please include your class diagram as an important reference.

For each class define the data fields, methods.

RAGPipeline

Purpose: Orchestrates the complete Retrieval-Augmented Generation flow from query to response.

Data Fields:

• retriever: DocumentRetriever - Document retrieval component
• contextManager: ContextManager - Conversation context handler
• promptBuilder: PromptBuilder - Prompt construction component
• llmConnector: LLMConnector - LLM interface
• chain: Chain - LangChain Chain object coordinating components
• pipelineConfig: Map<String, Any> - Configuration settings
• executionMetrics: ExecutionMetrics - Performance tracking

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
process(userQuery: String, userId: String): RAGResponse	Executes full RAG pipeline	userQuery: user question, userId: user identifier	RAGResponse object with answer	All components initialized, userId valid	Response generated, logged, metrics updated	RAGException, PipelineException
retrieveContext(query: String): List<Document>	Retrieves relevant documents for query	query: search query string	List of retrieved Document objects	retriever initialized	Context docs selected and ranked	RetrievalException, VectorStoreException
generateResponse(query: String, documents: List<Document>, context: ConversationContext): String	Generates response using LLM	query: user query, documents: context docs, context: history	Response string	LLM ready, documents provided, context valid	Response generated with citations	LLMException, GenerationException
validateResponse(response: String, sourceDocuments: List<Document>): Boolean	Validates response quality and relevance	response: generated response, sourceDocuments: used docs	Boolean indicating validation result	response not empty, documents provided	Validation score computed and logged	ValidationException
handleFallback(originalQuery: String, error: Exception): String	Handles pipeline failures with fallback	originalQuery: original user query, error: exception thrown	Fallback response string	original error caught, fallback ready	Fallback response returned, error logged	FallbackException

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ContextManager

Purpose: Maintains conversation history and manages context windows for multi-turn conversations.

Data Fields:

• conversationHistory: List<Message> - Ordered list of messages
• contextWindow: int - Maximum number of previous messages to keep
• userId: String - User ID for this conversation
• sessionStartTime: LocalDateTime - When conversation started
• lastMessageTime: LocalDateTime - Timestamp of last message
• contextSummary: String - Summary of earlier conversation

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
addMessage(role: Role, content: String): void	Adds user or assistant message to history	role: USER or ASSISTANT, content: message text	void	content not empty	Message appended, timestamp recorded	InvalidMessageException
getContext(): ConversationContext	Retrieves current conversation context	none	ConversationContext object	history not empty	Context object returned with full history	none
trimHistory(): void	Removes oldest messages if exceeding context window	none	void	history populated	Excess messages removed, summary updated	none
getSummary(maxLength: int): String	Gets concise summary of conversation	maxLength: max chars for summary	Summary string	history not empty	Summary generated and cached	SummaryException
getRelevantContext(query: String, maxMessages: int): List<Message>	Filters history for query-relevant messages	query: current query, maxMessages: limit	Filtered list of Message objects	history not empty, query provided	Most relevant messages selected	ContextFilterException
clearHistory(): void	Clears conversation history	none	void	none	History cleared, session ended	none
exportConversation(): List<Message>	Exports full conversation for logging	none	List of all Message objects	history not empty	Conversation exported, formatted	ExportException

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LLMConnector

Purpose: Abstracts LLM interactions using LangChain, supporting multiple providers (OpenAI, Claude, etc.).

Data Fields:

• llmProvider: String - Provider name (OPENAI, ANTHROPIC, etc.)
• apiKey: String - API authentication key
• modelName: String - Specific model identifier
• temperature: Float - Response randomness (0-1)
• maxTokens: int - Maximum output length
• retryPolicy: RetryPolicy - Retry configuration
• requestCache: Map<String, String> - Cache of responses

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
generate(prompt: String): String	Generates single response from prompt	prompt: full prompt text	Generated response string	LLM initialized, API key valid, prompt provided	Response returned and cached	LLMException, APIException, RateLimitException
streamResponse(prompt: String, callback: StreamCallback): void	Streams response token-by-token for real-time UI	prompt: full prompt, callback: token handler	void	LLM ready, streaming supported	Tokens streamed to callback as generated	StreamingException, LLMException
validateResponse(response: String, constraints: List<Constraint>): Boolean	Validates response meets quality constraints	response: generated text, constraints: validation rules	Boolean validation result	response not empty, constraints defined	Validation result computed	ValidationException
setTemperature(temperature: Float): void	Configures response randomness	temperature: value 0.0-1.0	void	0 <= temperature <= 1	Temperature parameter updated	InvalidParameterException
setMaxTokens(maxTokens: int): void	Sets maximum response length	maxTokens: token limit	void	maxTokens > 0	Token limit updated	InvalidParameterException
testConnection(): Boolean	Verifies LLM API connectivity	none	true if connected, false otherwise	API key configured	Connection status determined	ConnectionException
getUsageStats(): UsageStats	Retrieves API usage and cost information	none	UsageStats object with metrics	requests made	Usage stats returned	StatsException

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PromptBuilder

Purpose: Constructs optimized prompts for LLM by combining retrieved documents, context, and instructions.

Data Fields:

• systemPromptTemplate: String - System role instruction template
• userPromptTemplate: String - User query template
• documentTemplate: String - Template for formatting documents
• examplePrompts: Map<Intent, String> - Few-shot examples by intent
• promptConfig: Map<String, Any> - Configuration parameters
• citationFormat: CitationFormat - Format for citations

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
buildSystemPrompt(context: SystemContext): String	Builds system role and guidelines prompt	context: SystemContext with company info	System prompt string	context populated	System prompt formatted and ready	PromptException
buildUserPrompt(query: String, documents: List<Document>, context: ConversationContext): String	Assembles full user prompt with context	query: user question, documents: retrieved docs, context: history	Complete user prompt string	query not empty, documents provided	Prompt assembled with formatting	PromptBuildException
formatDocuments(documents: List<Document>): String	Formats documents for inclusion in prompt	documents: list of Document objects	Formatted document string	documents not empty	Documents formatted with metadata	FormattingException
addCitations(documents: List<Document>): String	Adds source citations for documents	documents: source documents	Citation formatted string	documents have source URLs	Citations formatted according to style	CitationException
getExamplePrompt(intent: Intent): String	Retrieves few-shot example for intent type	intent: detected intent	Example prompt string	examplePrompts loaded, intent valid	Example fetched for use in prompt	PromptNotFoundException
optimizePromptLength(prompt: String, maxLength: int): String	Truncates prompt while preserving quality	prompt: full prompt, maxLength: char limit	Optimized prompt string	prompt not empty, maxLength > 0	Prompt trimmed intelligently	OptimizationException
validatePrompt(prompt: String): PromptValidation	Validates prompt structure and content	prompt: assembled prompt	PromptValidation with score and issues	prompt not empty	Validation result computed	ValidationException

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ChatbotOrchestrator

Purpose: Main controller orchestrating all RAG pipeline components and managing conversation flow.

Data Fields:

• ragPipeline: RAGPipeline - RAG pipeline instance
• queryProcessor: QueryProcessor - Query processing component
• slackHandler: SlackBotHandler - Slack integration
• userProfileManager: UserProfileManager - User management
• expertMatcher: ExpertMatcher - Expert matching
• fallbackSearchHandler: FallbackSearchHandler - Fallback search
• conversationManagers: Map<String, ContextManager> - Per-user conversation contexts
• orchestrationMetrics: Metrics - Performance and usage metrics

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
handleQuery(query: String, userId: String, channelId: String): void	Main entry point handling user query	query: user question, userId: user ID, channelId: Slack channel	void	query not empty, userId/channelId valid	Response sent to user, interaction logged	OrchestrationException
manageConversation(userId: String): ConversationContext	Gets or creates conversation context for user	userId: user identifier	ConversationContext object	userId not empty	Conversation context retrieved/created	ConversationException
processUserQuery(query: String, userId: String): ProcessedQuery	Processes query through pipeline	query: user input, userId: user	ProcessedQuery with parsed intent	query not empty	Query fully processed	ProcessingException
generateContextualResponse(query: String, context: ConversationContext): String	Creates response with context awareness	query: current query, context: conversation history	Response string	query and context provided	Response generated with context	ResponseException
routeToExpert(query: String, userId: String): UserProfile	Routes complex queries to experts	query: user question, userId: requesting user	Expert UserProfile	query valid, user exists	Expert identified and notified	ExpertRoutingException
handleSpecialCommands(command: String, userId: String): String	Processes special bot commands	command: command string, userId: user	Command response	command recognized	Command executed, response returned	CommandException
getMetrics(): Metrics	Retrieves performance and usage metrics	none	Metrics object	orchestrator active	Current metrics returned	none
shutdown(): void	Gracefully shuts down all components	none	void	orchestrator running	All components stopped, connections closed	ShutdownException
initialize(): void	Initializes all components in dependency order	none	void	configuration loaded	All components ready to use	InitializationException

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FallbackSearchHandler

Purpose: Implements fallback search strategies when internal documentation is insufficient.

Data Fields:

• searchEngines: Map<String, SearchProvider> - External search providers
• sourceValidator: SourceValidator - Validates search results
• fallbackConfig: Map<String, Any> - Fallback configuration
• resultCache: Map<String, List<SearchResult>> - Cache of search results
• allowedDomains: List<String> - Whitelisted domains for fallback

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
searchExternal(query: String, engines: List<String>): List<SearchResult>	Searches external sources	query: search query, engines: search providers	List of SearchResult objects	query not empty, engines valid	Results retrieved from engines	SearchException, ExternalServiceException
validateSource(result: SearchResult): Boolean	Validates search result source credibility	result: SearchResult to validate	true if valid source	result has URL and content	Source validation completed	ValidationException
rankResults(results: List<SearchResult>, originalQuery: String): List<SearchResult>	Ranks search results by relevance	results: unranked results, originalQuery: reference query	Ranked list of SearchResult objects	results not empty	Results sorted by relevance score	RankingException
filterByDomain(results: List<SearchResult>): List<SearchResult>	Filters results to allowed domains	results: results to filter	Filtered SearchResult list	allowedDomains configured	Results filtered by domain whitelist	none
summarizeExternalContent(content: String): String	Creates summary of external source	content: full text	Summary string	content not empty	Summary generated and returned	SummarizationException
determineFallbackNeed(internalResults: List<Document>): Boolean	Checks if fallback search needed	internalResults: retrieved documents	true if fallback needed	internalResults evaluated	Fallback decision made	none
addToWhitelist(domain: String, category: String): void	Adds domain to approved sources	domain: domain name, category: category	void	domain valid format	Domain added to whitelist	ValidationException
removeFromWhitelist(domain: String): void	Removes domain from approved sources	domain: domain to remove	void	domain in whitelist	Domain removed from whitelist	DomainNotFoundException

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ErrorHandler

Purpose: Manages error handling, logging, and graceful fallbacks for various failure scenarios.

Data Fields:

• errorStrategies: Map<ErrorType, ErrorStrategy> - Error type handlers
• fallbackResponses: Map<ErrorType, String> - Fallback response messages
• notificationManager: NotificationManager - Admin error notifications
• errorLogger: Logger - Error logging instance
• recoveryStrategies: Map<ErrorType, RecoveryStrategy> - Recovery procedures
• errorThresholds: Map<ErrorType, int> - Error rate thresholds

Methods:

Method	Purpose	Parameters	Return Type	Pre-conditions	Post-conditions	Exceptions
handleTimeout(requestId: String, operation: String): String	Handles operation timeouts	requestId: operation ID, operation: operation name	Fallback response string	timeout logged	Timeout handled, error wrapped	TimeoutException
handleNoResults(query: String, context: ConversationContext): String	Handles queries with no results	query: user query, context: conversation context	Response string	query not empty	No results handled gracefully	none
handleRateLimiting(userId: String, service: String): void	Handles rate limit errors	userId: user ID, service: service name	void	none	Rate limit logged, user notified	RateLimitException
alertAdmin(error: Exception, severity: Severity): void	Notifies admin of critical errors	error: exception, severity: error level	void	error not null, admin configured	Admin notified via configured channel	NotificationException
handleDatabaseError(error: SQLException): String	Handles database errors	error: SQL exception	Fallback response	error not null	Error logged, offline mode activated if needed	DatabaseException
handleLLMError(error: LLMException): String	Handles LLM API errors	error: LLM exception	Fallback response	error not null	Error logged, alternative LLM tried if available	LLMException
logDetailedError(error: Exception, context: Map<String, Any>): void	Logs detailed error with full context	error: exception, context: contextual info	void	error not null	Error with full stack trace logged	LoggingException
getErrorMetrics(): ErrorMetrics	Retrieves error rate and metrics	none	ErrorMetrics object	error tracking active	Error metrics computed	MetricsException
registerErrorStrategy(errorType: ErrorType, strategy: ErrorStrategy): void	Registers custom error handler	errorType: error type, strategy: handler	void	errorType valid	Strategy registered for error type	none
shouldRetry(error: Exception): Boolean	Determines if operation should be retried	error: exception raised	true if retryable, false otherwise	error type recognized	Retry decision made	none

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The purpose of the class.

The purpose of each data field.

The purpose of each method

Pre-conditions if any.

Post-conditions if any.

Parameters and data types

Return value and output variables

Exceptions thrown* (PLEASE see note below for details).

An example of an auto-generated and then augmented API specification is here (Fiscal Design Document 2_API.docx )

This group developed their API documentation by hand (Design Document Part 2 API-1_MovieMatch.docx )

*At the top level, or where appropriate, all exceptions should be caught and an error message that is meaningful to the user generated. It is not OK to say ("xxxx has encountered a problem and will now close (OK?)". Error messages and recovery procedures should be documented in the User’s Manual.