swift - The Adapter Pattern

This pattern allows two objects that provide related functionality to work together even when they have incompatible APIs.

Diagram:

client:

let search = SearchTool(dataSources: SalesDataSource(),DevelopmentDataSource());

println("--List--");

for ein search.employees {

println("Name:(e.name)");

}

println("--Search--");

for ein search.search("VP",type: SearchTool.SearchType.TITLE) {

println("Name:(e.name),Title:(e.title)");

}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

pattern:

class SearchTool {

enum SearchType {

case NAME; case TITLE;

}

privatelet sources:[EmployeeDataSource];

init(dataSources: EmployeeDataSource...) {

self.sources = dataSources;

}

var employees:[Employee] {

var results = [Employee]();

for source insources {

results += source.employees;

}

return results;

}

func search(text:String,type:SearchType) -> [Employee] {

var results = [Employee]();

for source insources {

results += type== SearchType.NAME ? source.searchByName(text)

: source.searchByTitle(text);

}

return results;

}

}

///

class DataSourceBase :EmployeeDataSource {

var employees = [Employee]();

func searchByName(name: String) -> [Employee] {

return search({e -> Bool in

return e.name.rangeOfString(name) != nil;

});

}

func searchByTitle(title: String) -> [Employee] {

return search({e -> Bool in

return e.title.rangeOfString(title) != nil;

})

}

privatefunc search(selector:(Employee ->Bool)) -> [Employee] {

var results = [Employee]();

for e in employees {

if (selector(e)) {

results.append(e);

}

}

return results;

}

}

class SalesDataSource :DataSourceBase {

override init() {

super.init();

employees.append(Employee(name:"Alice",title: "VP of Sales"));

employees.append(Employee(name:"Bob",title: "Account Exec"));

}

}

class DevelopmentDataSource :DataSourceBase {

override init() {

super.init();

employees.append(Employee(name:"Joe",title: "VP of Development"));

employees.append(Employee(name:"Pepe",title: "Developer"));

}

}

/////////

struct Employee {

var name:String;

var title:String;

}

protocol EmployeeDataSource {

var employees:[Employee] {get };

func searchByName(name:String) -> [Employee];

func searchByTitle(title:String) -> [Employee];

}

（编辑：李大同）

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