Merge pull request #8125 from eugenp/revert-8119-BAEL-3275-2

Revert "BAEL-3275: Using blocking queue for pub-sub"

patterns/design-patterns-functional/src/main/java/com/baeldung/currying/Letter.java

@@ -0,0 +1,110 @@
+package com.baeldung.currying;
+
+import java.time.LocalDate;
+import java.util.Objects;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+public class Letter {
+    private String returningAddress;
+    private String insideAddress;
+    private LocalDate dateOfLetter;
+    private String salutation;
+    private String body;
+    private String closing;
+
+    Letter(String returningAddress, String insideAddress, LocalDate dateOfLetter, String salutation, String body, String closing) {
+        this.returningAddress = returningAddress;
+        this.insideAddress = insideAddress;
+        this.dateOfLetter = dateOfLetter;
+        this.salutation = salutation;
+        this.body = body;
+        this.closing = closing;
+    }
+
+    Letter(String salutation, String body) {
+        this(null, null, LocalDate.now(), salutation, body, null);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Letter letter = (Letter) o;
+        return Objects.equals(returningAddress, letter.returningAddress) &&
+          Objects.equals(insideAddress, letter.insideAddress) &&
+          Objects.equals(dateOfLetter, letter.dateOfLetter) &&
+          Objects.equals(salutation, letter.salutation) &&
+          Objects.equals(body, letter.body) &&
+          Objects.equals(closing, letter.closing);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(returningAddress, insideAddress, dateOfLetter, salutation, body, closing);
+    }
+
+    @Override
+    public String toString() {
+        return "Letter{" + "returningAddress='" + returningAddress + '\'' + ", insideAddress='" + insideAddress + '\''
+            + ", dateOfLetter=" + dateOfLetter + ", salutation='" + salutation + '\'' + ", body='" + body + '\''
+            + ", closing='" + closing + '\'' + '}';
+    }
+
+    static Letter createLetter(String salutation, String body) {
+        return new Letter(salutation, body);
+    }
+
+    static BiFunction<String, String, Letter> SIMPLE_LETTER_CREATOR = //
+        (salutation, body) -> new Letter(salutation, body);
+
+    static Function<String, Function<String, Letter>> SIMPLE_CURRIED_LETTER_CREATOR = //
+        saluation -> body -> new Letter(saluation, body);
+
+    static Function<String, Function<String, Function<LocalDate, Function<String, Function<String, Function<String, Letter>>>>>> LETTER_CREATOR = //
+      returnAddress
+          -> closing
+          -> dateOfLetter
+          -> insideAddress
+          -> salutation
+          -> body
+          -> new Letter(returnAddress, insideAddress, dateOfLetter, salutation, body, closing);
+
+    static AddReturnAddress builder() {
+        return returnAddress
+            -> closing
+            -> dateOfLetter
+            -> insideAddress
+            -> salutation
+            -> body
+            -> new Letter(returnAddress, insideAddress, dateOfLetter, salutation, body, closing);
+    }
+
+    interface AddReturnAddress {
+        Letter.AddClosing withReturnAddress(String returnAddress);
+    }
+
+    interface AddClosing {
+        Letter.AddDateOfLetter withClosing(String closing);
+    }
+
+    interface AddDateOfLetter {
+        Letter.AddInsideAddress withDateOfLetter(LocalDate dateOfLetter);
+    }
+
+    interface AddInsideAddress {
+        Letter.AddSalutation withInsideAddress(String insideAddress);
+    }
+
+    interface AddSalutation {
+        Letter.AddBody withSalutation(String salutation);
+    }
+
+    interface AddBody {
+        Letter withBody(String body);
+    }
+}