init

Author: chenm

.gitignore

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+target/
+.idea/
+**/target/

ch01-introduction/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>functional-programming-in-java</artifactId>
+        <groupId>com.matrix</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>ch01-introduction</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.matrix</groupId>
+            <artifactId>fpjava-common</artifactId>
+            <version>${version}</version>
+        </dependency>
+    </dependencies>
+
+</project>

ch01-introduction/src/.DS_Store

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+package com.fpinjava.introduction.listing01_01;
+
+public class CreditCard {
+
+  private int total;
+
+  public void charge(int price) {
+    this.total += price;
+  }
+
+  public int getTotal() {
+    return total;
+  }
+
+}

ch01-introduction/src/main/.DS_Store

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+package com.fpinjava.introduction.listing01_01;
+
+public class Donut {
+
+  public static final int price = 2;
+
+}

ch01-introduction/src/main/java/.DS_Store

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+package com.fpinjava.introduction.listing01_01;
+
+public class DonutShop {
+  
+  public static Donut buyDonut(CreditCard creditCard) {
+    Donut donut = new Donut();
+    creditCard.charge(Donut.price);
+    return donut;
+  }
+}

ch01-introduction/src/main/java/com/.DS_Store

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+package com.fpinjava.introduction.listing01_02;
+
+public class CreditCard {
+
+  public void charge(int price) {
+    // Charge the credit card
+  }
+
+}

ch01-introduction/src/main/java/com/fpinjava/.DS_Store

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+package com.fpinjava.introduction.listing01_02;
+
+public class Donut {
+
+  public static final int price = 2;
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/.DS_Store

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+package com.fpinjava.introduction.listing01_02;
+
+public class DonutShop {
+  
+  public static Tuple<Donut, Payment> buyDonut(CreditCard creditCard) {
+    return new Tuple<>(new Donut(), new Payment(creditCard, Donut.price));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_01/CreditCard.java

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+package com.fpinjava.introduction.listing01_02;
+
+public class Payment {
+  
+  public final CreditCard creditCard;
+  public final int amount;
+
+  public Payment(CreditCard creditCard, int amount) {
+    this.creditCard = creditCard;
+    this.amount = amount;
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_01/Donut.java

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+package com.fpinjava.introduction.listing01_02;
+
+public class Tuple<T, U> {
+
+  public final T _1;
+  public final U _2;
+
+  public Tuple(T t, U u) {
+    this._1 = t;
+    this._2 = u;
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_01/DonutShop.java

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+package com.fpinjava.introduction.listing01_03;
+
+public class CreditCard {
+
+	public void charge(int price) {
+		// Charge the credit card
+	}
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_02/CreditCard.java

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+package com.fpinjava.introduction.listing01_03;
+
+public class Donut {
+	
+	public static final int price = 2;
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_02/Donut.java

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+package com.fpinjava.introduction.listing01_03;
+
+import com.fpinjava.common.Tuple;
+
+public class DonutShop {
+  
+  public static Tuple<Donut, Payment> buyDonut(CreditCard creditCard) {
+    return new Tuple<>(new Donut(), new Payment(creditCard, Donut.price));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_02/DonutShop.java

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+package com.fpinjava.introduction.listing01_03;
+
+public class Payment {
+  
+  public final CreditCard creditCard;
+  public final int amount;
+
+  public Payment(CreditCard creditCard, int amount) {
+    this.creditCard = creditCard;
+    this.amount = amount;
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_02/Payment.java

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+package com.fpinjava.introduction.listing01_03;
+
+public class Tuple<T, U> {
+
+  public final T _1;
+  public final U _2;
+
+  public Tuple(T t, U u) {
+    this._1 = t;
+    this._2 = u;
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_02/Tuple.java

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+package com.fpinjava.introduction.listing01_04;
+
+public class CreditCard {
+
+	public void charge(int price) {
+		// Charge the credit card
+	}
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_03/CreditCard.java

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+package com.fpinjava.introduction.listing01_04;
+
+public class Donut {
+	
+	public static final int price = 2;
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_03/Donut.java

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+package com.fpinjava.introduction.listing01_04;
+
+import com.fpinjava.common.Tuple;
+
+public class DonutShop {
+
+  public static Tuple<Donut, Payment> buyDonut(final CreditCard cc) {
+    return new Tuple<>(new Donut(), new Payment(cc, Donut.price));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_03/DonutShop.java

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+package com.fpinjava.introduction.listing01_04;
+
+
+public class Payment {
+  
+  public final CreditCard creditCard;
+  public final int amount;
+
+  public Payment(CreditCard creditCard, int amount) {
+    this.creditCard = creditCard;
+    this.amount = amount;
+  }
+  
+  public Payment combine(Payment payment) {
+    if (creditCard.equals(payment.creditCard)) {
+      return new Payment(creditCard, amount + payment.amount); 
+    } else {
+      throw new IllegalStateException("Cards don't match.");
+    }
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_03/Payment.java

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+package com.fpinjava.introduction.listing01_05;
+
+public class CreditCard {
+
+	public void charge(int price) {
+		// Charge the credit card
+	}
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_03/Tuple.java

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+package com.fpinjava.introduction.listing01_05;
+
+public class Donut {
+	
+	public static final int price = 2;
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_04/CreditCard.java

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+package com.fpinjava.introduction.listing01_05;
+
+import static com.fpinjava.common.List.fill;
+import com.fpinjava.common.List;
+import com.fpinjava.common.Tuple;
+
+public class DonutShop {
+
+  public static Tuple<Donut, Payment> buyDonut(final CreditCard creditCard) {
+    return new Tuple<>(new Donut(), new Payment(creditCard, Donut.price));
+  }
+
+  public static Tuple<List<Donut>, Payment> buyDonuts(final int quantity,
+                                               final CreditCard creditCard) {
+    return new Tuple<>(fill(quantity, Donut::new),
+                               new Payment(creditCard, Donut.price * quantity));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_04/Donut.java

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+package com.fpinjava.introduction.listing01_05;
+
+
+public class Payment {
+
+  public final CreditCard creditCard;
+  public final int amount;
+
+  public Payment(CreditCard creditCard, int amount) {
+    this.creditCard = creditCard;
+    this.amount = amount;
+  }
+
+  public Payment combine(Payment payment) {
+    if (creditCard.equals(payment.creditCard)) {
+      return new Payment(creditCard, amount + payment.amount);
+    } else {
+      throw new IllegalStateException("Cards don't match.");
+    }
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_04/DonutShop.java

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+package com.fpinjava.introduction.listing01_06;
+
+public class CreditCard {
+
+	public void charge(int price) {
+		// Charge the credit card
+	}
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_04/Payment.java

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+package com.fpinjava.introduction.listing01_06;
+
+public class Donut {
+	
+	public static final int price = 2;
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_05/CreditCard.java

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+package com.fpinjava.introduction.listing01_06;
+
+import static com.fpinjava.common.List.fill;
+import com.fpinjava.common.List;
+import com.fpinjava.common.Tuple;
+
+public class DonutShop {
+
+  public static Tuple<Donut, Payment> buyDonut(final CreditCard cc) {
+    return new Tuple<>(new Donut(), new Payment(cc, Donut.price));
+  }
+
+  public static Tuple<List<Donut>, Payment> buyDonuts(final int n,
+                                                      final CreditCard creditCard) {
+    return new Tuple<>(fill(n, Donut::new),
+                               new Payment(creditCard, Donut.price * n));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_05/Donut.java

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+package com.fpinjava.introduction.listing01_06;
+
+import com.fpinjava.common.List;
+
+public class Payment {
+
+  public final CreditCard creditCard;
+  public final int amount;
+
+  public Payment(CreditCard creditCard, int amount) {
+    this.creditCard = creditCard;
+    this.amount = amount;
+  }
+
+  public Payment combine(Payment payment) {
+    if (creditCard.equals(payment.creditCard)) {
+      return new Payment(creditCard, amount + payment.amount);
+    } else {
+      throw new IllegalStateException("Cards don't match.");
+    }
+  }
+
+  public static List<Payment> groupByCard(List<Payment> payments) {
+    return payments
+        .groupBy(x -> x.creditCard)
+        .values()
+        .map(x -> x.reduce(c1 -> c1::combine));
+  }
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_05/DonutShop.java

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+package com.fpinjava.introduction.listing01_01;
+
+import static org.junit.Assert.*;
+import static com.fpinjava.introduction.listing01_01.DonutShop.buyDonut;
+
+import org.junit.Test;
+
+import com.fpinjava.introduction.listing01_01.Donut;
+import com.fpinjava.introduction.listing01_01.CreditCard;
+
+public class DonutShopTest {
+
+  @Test
+  public void testBuyCoffee() {
+    CreditCard crediCard = new CreditCard();
+    buyDonut(crediCard);
+    buyDonut(crediCard);
+    assertEquals(Donut.price * 2, crediCard.getTotal());
+  }
+
+}

ch01-introduction/src/main/java/com/fpinjava/introduction/listing01_05/Payment.java

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+package com.fpinjava.introduction.listing01_02;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class DonutShopTest {
+
+  @Test
+  public void testBuyDonut() {
+    CreditCard creditCard = new CreditCard();
+    Tuple<Donut, Payment> purchase = DonutShop.buyDonut(creditCard);
+    assertEquals(Donut.price, purchase._2.amount);
+    assertEquals(creditCard, purchase._2.creditCard);
+  }
+}