# APIs

[](https://hackmd.io/SzpXRChpTVSbmjd8zcvYSw)

## PKB Abstract API

### Component: PKB
**Overview**: Stores the abstracted information extracted from the source code.

**Requirements**:
* STMT requires stmtRef and STMT_TYPE
* VAR requires stmtRef, entRef and VAR_TYPE
#### API:

1. PROC[] getProcTable()
* Required only in iter 2
* Description: Returns a list of PROC. If the procTable is empty, return an empty list.
2. list[string] getDesignEntity(DesignEntity de)
* Description: Returns a list of strings with the corresponding data to that Design Entity.
If there are no such types of DesignEntity, return an empty list.
3. list<tuple<DesignEntity, string>> GetFollows(string stmt)
* Description: Returns a list containing 1 string which follows stmt.
If there is no stmt that follows, return an empty list.
4. list<tuple<DesignEntity, string>> GetPrevious(string stmt)
* Description: Returns a list containing 1 string, x, where stmt follows x.
If there is no previous stmt, return an empty list.
5. list<tuple<DesignEntity, string>> GetFollowsStar(string stmt)
* Description: Returns a list of stmt which follows* stmt.
If there is no string that follows, return an empty list.
6. list<tuple<DesignEntity, string>> GetPreviousStar(string stmt)
* Description: Returns a list of stmt, x, where stmt follows* x.
If there is no previous string, return an empty list.
7. list<tuple<DesignEntity, string>> GetParent(string stmt)
* Description: Returns a list containing 1 stmt, s, where Parent(s, stmt)
8. list<tuple<DesignEntity, string>> GetChild(string stmt)
* Description: Returns a list containing 1 stmt, s, where Parent(stmt, s)
9. list<tuple<DesignEntity, string>> GetParentStar(string stmt)
* Description: Returns a list containing 1 stmt, s, where Parent*(s, stmt)
10. list<tuple<DesignEntity, string>> GetChildStar(string stmt)
* Description: Returns a list containing 1 stmt, s, where Parent*(stmt, s)
11. list<tuple<DesignEntity, string>> GetUsedBy(string stmt)
* Description: Returns a list of VAR, v, where Uses (stmt, v). Empty list otherwise.
12. list<tuple<DesignEntity, string>> GetUses(string var)
* Description: Returns a list of stmt, s, where Uses (s, v). Empty list otherwise.
13. list<tuple<DesignEntity, string>> GetModifiedBy(string stmt)
* Description: Returns a list of VAR, v, where Modifies (stmt, v). Empty list otherwise.
14. list<tuple<DesignEntity, string>> GetModifies(string var)
* Description: Returns a list of stmt, s, where Modifies (s, v). Empty list otherwise.
15. vector[AssignEntity] getPatternByAssign(string stmtRef)
* Description: Returns a list of a single OBJECT containing varName and expression.
16. vector[AssignEntity] getPatternByVariable(string varName)
* Description: Returns a list of OBJECTs(?) each containing varName(LHS) and expression(RHS).

## Query Processor Abstract API

### List of Components (Only lists important ones)
1. QueryExtractor
2. QueryOptimizer
3. QueryEvaluator
4. QueryProjector

### QueryExtractor
**Overview**: `QueryExtractor` is a facade that calls subcomponents (`QueryTokenizer`, `QueryParser`, `QueryValidator`) in order to tokenize, parse and validate the user query and populate the relevant information inside the query objects.

#### API
1. VOID ExtractQuery(STRING query)
* Description: Processes the query string, modifying the query objects in QueryExtractor in-place with the extracted information.

### QueryOptimizer
**Overview**: `QueryOptimizer` executes extra logic on the initial query object, in order to group the clauses in strategic ways to increase performance during evaluation.

#### API
1. static void GroupClauses(std::vector<Clause*>* clauses, std::list<Group*>* groups, Synonym* target);
* Description: Groups clauses (queries) that should be evaluated together, based on existence of common synonyms. The newly formed Groups of clauses are added in-place to the Groups data structure of the query object. Note: For iteration 1, the grouping algorithm has a rudimentary implementation as a maximum of 1 such that and 1 pattern clause is expected.

### QueryEvaluator
**Overview**: `QueryEvaluator` receives and further processes the query objects received from `QueryExtractor`, and evaluates the queries.

#### API
1. VOID QueryEvaluator(std::list[Synonym] syn_list, Synonym target, std::list<Group*> groups, PKB pkb);
* Description: Initialiser for the QueryEvaluator instance, which takes in the query objects representing a valid parsed query, and an instance of the PKB object.

### QueryProjector
**Overview**: `QueryProjector` receives raw results of query evaluation, and formats them before passing the results to the autotester.

#### API
1. std::list<std::string> FormatQuery(std::vector<std::string> results);
* Description: receives raw results of query evaluation as a vector of strings, and formats them before passing the list results to the autotester.

## Template for Abstract API

### \<Insert Module/Component Name\>
**Overview**: <insert purpose/responsibility of module>
#### API
1. RETURN_TYPE functionName(ARG_TYPE argName)
* Requires: \<insert precondition\>
* Description: \<insert description for abstract API call\>
2. RETURN_TYPE functionName(ARG_TYPE argName)
* Requires: \<insert precondition\>
* Description: \<insert description for abstract API call\>

## PKBQueryReceiver to DBManager API

####API

1. std::vector<Entity*> GetRelationship(PKBRelRefs ref, std::string entity);

2. std::vector<Entity*> GetRelationshipByType(PKBRelRefs, DesignEntity, vector<Entity*>, Enum);
- Note that its either use kNoScoped vs kLeftScoped or kRightScoped

3. std::vector<std::tuple<Entity*, Entity*>> GetRelationshipByTypes(PKBRelRefs, DesignEntity, DesignEntity, vector<Entity*>, vector<Entity*>, Enum);

4. std::vector<Entity*> GetDesignEntities(DesignEntity de);

5. std::vector<Entity*> GetAssignEntityByStmtRef(std::string stmtRef);
6. std::vector<Entity*> GetAssignEntityByVariable(std::string variable);
7. std::vector<Entity*> GetWhileEntityByStmtRef(std::string stmtRef);
8. std::vector<Entity*> GetWhileEntityByVariable(std::string variable);
9. std::vector<Entity*> GetIfEntityByStmtRef(std::string stmtRef);
10. std::vector<Entity*> GetIfEntityByVariable(std::string variable);

11. bool HasRelationship(PKBRelRefs);
12. bool HasRelationship(PKBRelRefs, DesignEntity, DesignEntity);
13. bool HasRelationship(PKBRelRefs, std::string, std::string);