Add Observer

README.md

@@ -4,4 +4,8 @@ Project that implements some design patterns using Java 13.
 
 - Strategy
 - Chain Of Responsibility
-- Template Method
+- Template Method
+- Decorator
+- State
+- Builder
+- Observer

src/observer/ActionAfterGeneratingNote.java

@@ -0,0 +1,7 @@
+package observer;
+
+public interface ActionAfterGeneratingNote {
+
+	void execute(Invoice invoice);
+
+}

src/observer/Annotation.txt

@@ -0,0 +1,21 @@
+###############################
+#          Observer           #
+###############################
+
+
+
+
+
+##### Language - EN
+
+
+- 
+
+
+##### Language - PT-BR
+
+- Quando o acoplamento da nossa classe está crescendo, ou quando temos diversas ações 
+diferentes a serem executadas após um determinado processo, podemos implementar o Observer.
+
+- Ele permite que diversas ações sejam executadas de forma transparente à classe principal, 
+reduzindo o acoplamento entre essas ações, facilitando a manutenção e evolução do código.

src/observer/BuilderInvoice.java

@@ -0,0 +1,66 @@
+package observer;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+public class BuilderInvoice {
+
+	private String companyName;
+	private String cnpj;
+	private List<NoteItem> allItems = new ArrayList<>();
+	private double grossAmountl;
+	private double taxes;
+	private String notes;
+	private LocalDate date;
+
+	private List<ActionAfterGeneratingNote> allActions;
+
+	public BuilderInvoice() {
+		this.allActions = new ArrayList<>();
+	}
+
+	public BuilderInvoice toCompany(String companyName) {
+		this.companyName = companyName;
+		return this; //Return this use for method in cascade for BUILDER
+	}
+
+	public BuilderInvoice withCnpj(String cnpj) {
+		this.cnpj = cnpj;
+		return this; //Return this use for method in cascade for BUILDER
+	}
+
+	public BuilderInvoice withItem(NoteItem item) {
+		this.allItems.add(item);
+		this.grossAmountl += item.getValue();
+		this.taxes = item.getValue() * 0.05;
+		return this; //Return this use for method in cascade for BUILDER
+	}
+
+	public BuilderInvoice withNotes(String notes) {
+		this.notes = notes;
+		return this; //Return this use for method in cascade for BUILDER
+	}
+
+	public BuilderInvoice onCurrentDate() {
+		this.date = LocalDate.now();
+		return this; //Return this use for method in cascade for BUILDER
+	}
+
+	public void addAction(ActionAfterGeneratingNote action) {
+		this.allActions.add(action);
+	}
+
+	public Invoice builder() {
+		Invoice invoice = new Invoice(companyName, cnpj, date, grossAmountl, taxes, allItems, notes);
+
+		// Observer
+		for (ActionAfterGeneratingNote actions : allActions) {
+			actions.execute(invoice);
+		}
+
+		return invoice;
+	}
+
+
+}

src/observer/EmailSender.java

@@ -0,0 +1,10 @@
+package observer;
+
+public class EmailSender implements ActionAfterGeneratingNote {
+
+	@Override
+	public void execute(Invoice invoice) {
+		System.out.println("Send e-mail...");
+	}
+
+}

src/observer/Invoice.java

@@ -0,0 +1,101 @@
+package observer;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Invoice {
+
+	private String companyName;
+	private String cnpj;
+	private LocalDate dateOfIssue;
+	private double grossAmountl;
+	private double taxes;
+	private List<NoteItem> allItems = new ArrayList<>();
+	private String notes;
+
+
+	public Invoice(String companyName, String cnpj, LocalDate dateOfIssue, double grossAmountl, double taxes,
+			List<NoteItem> allItems, String notes) {
+		super();
+		this.companyName = companyName;
+		this.cnpj = cnpj;
+		this.dateOfIssue = dateOfIssue;
+		this.grossAmountl = grossAmountl;
+		this.taxes = taxes;
+		this.allItems = allItems;
+		this.notes = notes;
+	}
+
+
+	public String getCompanyName() {
+		return companyName;
+	}
+
+
+	public void setCompanyName(String companyName) {
+		this.companyName = companyName;
+	}
+
+
+	public String getCnpj() {
+		return cnpj;
+	}
+
+
+	public void setCnpj(String cnpj) {
+		this.cnpj = cnpj;
+	}
+
+
+	public LocalDate getDateOfIssue() {
+		return dateOfIssue;
+	}
+
+
+	public void setDateOfIssue(LocalDate dateOfIssue) {
+		this.dateOfIssue = dateOfIssue;
+	}
+
+
+	public double getGrossAmountl() {
+		return grossAmountl;
+	}
+
+
+	public void setGrossAmountl(double grossAmountl) {
+		this.grossAmountl = grossAmountl;
+	}
+
+
+	public double getTaxes() {
+		return taxes;
+	}
+
+
+	public void setTaxes(double taxes) {
+		this.taxes = taxes;
+	}
+
+
+	public List<NoteItem> getAllItems() {
+		return allItems;
+	}
+
+
+	public void setAllItems(List<NoteItem> allItems) {
+		this.allItems = allItems;
+	}
+
+
+	public String getNotes() {
+		return notes;
+	}
+
+
+	public void setNotes(String notes) {
+		this.notes = notes;
+	}
+
+
+}

src/observer/InvoiceDao.java

@@ -0,0 +1,11 @@
+package observer;
+
+public class InvoiceDao implements ActionAfterGeneratingNote {
+
+	@Override
+	public void execute(Invoice invoice) {
+		System.out.println("Save invoice...");
+
+	}
+
+}

src/observer/NoteItem.java

@@ -0,0 +1,27 @@
+package observer;
+
+public class NoteItem {
+
+	private String name;
+	private double value;
+
+	public NoteItem(String name, double value) {
+		super();
+		this.name = name;
+		this.value = value;
+	}
+
+	public String getName() {
+		return name;
+	}
+	public void setName(String name) {
+		this.name = name;
+	}
+	public double getValue() {
+		return value;
+	}
+	public void setValue(double value) {
+		this.value = value;
+	}
+
+}

src/observer/ObserverMain.java

@@ -0,0 +1,34 @@
+package observer;
+
+public class ObserverMain {
+
+	public static void main(String[] args) {
+		System.out.println("--------------------------------------------- Begin Test Observer");
+
+
+		BuilderInvoice builderInvoice = new BuilderInvoice();
+
+		builderInvoice.toCompany("Murillo Pezzuol LTDA")
+			.withCnpj("987654321")
+			.withItem(new NoteItem("Notebook", 100))
+			.withNotes("Anottation....")
+			.onCurrentDate();
+
+		// Add to the list the actions that my observer will iterate
+		builderInvoice.addAction(new EmailSender());
+		builderInvoice.addAction(new InvoiceDao());
+		builderInvoice.addAction(new SmsSender());
+		builderInvoice.addAction(new Printer());
+
+		Invoice invoice = builderInvoice.builder();//Return Object Invoice
+
+
+		System.out.println("Gross Amountl: " + invoice.getGrossAmountl()); // 100
+
+		// OUT -> All registered actions and that our 'observer' has found and executed must be printed.
+
+
+		System.out.println("--------------------------------------------- End Test Observer");
+	}
+
+}

src/observer/Printer.java

@@ -0,0 +1,10 @@
+package observer;
+
+public class Printer implements ActionAfterGeneratingNote {
+
+	@Override
+	public void execute(Invoice invoice) {
+		System.out.println("Printer...");
+	}
+
+}

src/observer/SmsSender.java

@@ -0,0 +1,11 @@
+package observer;
+
+public class SmsSender implements ActionAfterGeneratingNote {
+
+	@Override
+	public void execute(Invoice invoice) {
+		System.out.println("Send SMS...");
+
+	}
+
+}