diff --git a/enterprise-patterns/front-controller-pattern/pom.xml b/enterprise-patterns/front-controller-pattern/pom.xml new file mode 100644 index 0000000000..eefd52a52d --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/pom.xml @@ -0,0 +1,41 @@ + + + 4.0.0 + + front-controller-pattern + war + + + enterprise-patterns-parent + com.baeldung.enterprise.patterns + 1.0.0-SNAPSHOT + + + + + javax.servlet + servlet-api + 2.5 + provided + + + + + + + org.apache.maven.plugins + maven-compiler-plugin + + + org.apache.maven.plugins + maven-war-plugin + 3.0.0 + + ${env.DEPLOYMENTS} + + + + + diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/FrontControllerServlet.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/FrontControllerServlet.java new file mode 100644 index 0000000000..4dfc12c050 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/FrontControllerServlet.java @@ -0,0 +1,45 @@ +package com.baeldung.enterprise.patterns.front.controller; + +import com.baeldung.enterprise.patterns.front.controller.commands.FrontCommand; +import com.baeldung.enterprise.patterns.front.controller.commands.UnknownCommand; + +import javax.servlet.ServletException; +import javax.servlet.http.HttpServlet; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import java.io.IOException; + +public class FrontControllerServlet extends HttpServlet { + @Override + protected void doGet( + HttpServletRequest request, + HttpServletResponse response + ) throws ServletException, IOException { + FrontCommand command = getCommand(request); + command.init(getServletContext(), request, response); + command.process(); + } + + private FrontCommand getCommand(HttpServletRequest request) { + try { + return (FrontCommand) getCommandClass(request) + .asSubclass(FrontCommand.class) + .newInstance(); + } catch (Exception e) { + throw new RuntimeException("Failed to get command!", e); + } + } + + private Class getCommandClass(HttpServletRequest request) { + try { + return Class.forName( + String.format( + "com.baeldung.enterprise.patterns.front.controller.commands.%sCommand", + request.getParameter("command") + ) + ); + } catch (ClassNotFoundException e) { + return UnknownCommand.class; + } + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/BookCommand.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/BookCommand.java new file mode 100644 index 0000000000..e858cd98a9 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/BookCommand.java @@ -0,0 +1,22 @@ +package com.baeldung.enterprise.patterns.front.controller.commands; + +import com.baeldung.enterprise.patterns.front.controller.data.Book; +import com.baeldung.enterprise.patterns.front.controller.data.Bookshelf; + +import javax.servlet.ServletException; +import java.io.IOException; + +public class BookCommand extends FrontCommand { + @Override + public void process() throws ServletException, IOException { + Book book = Bookshelf.getInstance() + .findByTitle(request.getParameter("title")); + if (book != null) { + request.setAttribute("book", book); + forward("book-found"); + } else { + request.setAttribute("books", Bookshelf.getInstance().getBooks()); + forward("book-notfound"); + } + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/FrontCommand.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/FrontCommand.java new file mode 100644 index 0000000000..12a008faeb --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/FrontCommand.java @@ -0,0 +1,32 @@ +package com.baeldung.enterprise.patterns.front.controller.commands; + +import javax.servlet.RequestDispatcher; +import javax.servlet.ServletContext; +import javax.servlet.ServletException; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import java.io.IOException; + +public abstract class FrontCommand { + protected ServletContext context; + protected HttpServletRequest request; + protected HttpServletResponse response; + + public void init( + ServletContext servletContext, + HttpServletRequest servletRequest, + HttpServletResponse servletResponse + ) { + this.context = servletContext; + this.request = servletRequest; + this.response = servletResponse; + } + + public abstract void process() throws ServletException, IOException; + + protected void forward(String target) throws ServletException, IOException { + target = String.format("/WEB-INF/jsp/%s.jsp", target); + RequestDispatcher dispatcher = context.getRequestDispatcher(target); + dispatcher.forward(request, response); + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/UnknownCommand.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/UnknownCommand.java new file mode 100644 index 0000000000..90103c8f42 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/commands/UnknownCommand.java @@ -0,0 +1,11 @@ +package com.baeldung.enterprise.patterns.front.controller.commands; + +import javax.servlet.ServletException; +import java.io.IOException; + +public class UnknownCommand extends FrontCommand { + @Override + public void process() throws ServletException, IOException { + forward("unknown"); + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Book.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Book.java new file mode 100644 index 0000000000..634e05c3a0 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Book.java @@ -0,0 +1,40 @@ +package com.baeldung.enterprise.patterns.front.controller.data; + +public class Book { + private String author; + private String title; + private Double price; + + public Book() { + } + + public Book(String author, String title, Double price) { + this.author = author; + this.title = title; + this.price = price; + } + + public String getAuthor() { + return author; + } + + public void setAuthor(String author) { + this.author = author; + } + + public String getTitle() { + return title; + } + + public void setTitle(String title) { + this.title = title; + } + + public Double getPrice() { + return price; + } + + public void setPrice(Double price) { + this.price = price; + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Bookshelf.java b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Bookshelf.java new file mode 100644 index 0000000000..142435e2e3 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/data/Bookshelf.java @@ -0,0 +1,32 @@ +package com.baeldung.enterprise.patterns.front.controller.data; + +import java.util.ArrayList; +import java.util.List; + +public class Bookshelf { + private static Bookshelf INSTANCE = new Bookshelf(); + private List books = new ArrayList<>(); + + public static Bookshelf getInstance() { + if (INSTANCE.books.size() == 0) { + INSTANCE.init(); + } + return INSTANCE; + } + + private void init() { + books.add(new Book("Wilson, Robert Anton & Shea, Robert", "Illuminati", 9.99)); + books.add(new Book("Fowler, Martin", "Patterns of Enterprise Application Architecture", 27.88)); + } + + public Book findByTitle(String title) { + return books.stream() + .filter(book -> book.getTitle().equalsIgnoreCase(title)) + .findFirst() + .orElse(null); + } + + public List getBooks() { + return books; + } +} diff --git a/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jboss-web.xml b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jboss-web.xml new file mode 100644 index 0000000000..db2d804135 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jboss-web.xml @@ -0,0 +1,6 @@ + + + + /front-controller/ + diff --git a/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-found.jsp b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-found.jsp new file mode 100644 index 0000000000..8fa82ee816 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-found.jsp @@ -0,0 +1,4 @@ +

Our Bookshelf contains this title:

+

${book.getTitle()}

+

Author: ${book.getAuthor()}

+ diff --git a/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-notfound.jsp b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-notfound.jsp new file mode 100644 index 0000000000..e8ce67ac96 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/book-notfound.jsp @@ -0,0 +1,2 @@ +

Our Bookshelf doesn't contains this title:

+

${param.get("title")}

diff --git a/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/unknown.jsp b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/unknown.jsp new file mode 100644 index 0000000000..d348f757d9 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/jsp/unknown.jsp @@ -0,0 +1 @@ +

Sorry, this command is not known!

diff --git a/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/web.xml b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/web.xml new file mode 100644 index 0000000000..372ee42800 --- /dev/null +++ b/enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/web.xml @@ -0,0 +1,11 @@ + + + + front-controller + com.baeldung.enterprise.patterns.front.controller.FrontControllerServlet + + + front-controller + / + + diff --git a/enterprise-patterns/pom.xml b/enterprise-patterns/pom.xml new file mode 100644 index 0000000000..2fba12547f --- /dev/null +++ b/enterprise-patterns/pom.xml @@ -0,0 +1,35 @@ + + + 4.0.0 + + com.baeldung.enterprise.patterns + enterprise-patterns-parent + pom + + front-controller-pattern + + + + com.baeldung + parent-modules + 1.0.0-SNAPSHOT + + + + + + + org.apache.maven.plugins + maven-compiler-plugin + 3.5.1 + + 1.8 + 1.8 + + + + + +