added solid code (#6226)

patterns/principles/solid/pom.xml

@@ -0,0 +1,23 @@
+<?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">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>solid/artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+
+    <dependencies>
+        <!-- https://mvnrepository.com/artifact/junit/junit -->
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+</project>

patterns/principles/solid/src/main/java/com/baeldung/d/Keyboard.java

@@ -0,0 +1,4 @@
+package com.baeldung.d;
+
+public class Keyboard {
+}

patterns/principles/solid/src/main/java/com/baeldung/d/Monitor.java

@@ -0,0 +1,6 @@
+package com.baeldung.d;
+
+public class Monitor {
+
+
+}

patterns/principles/solid/src/main/java/com/baeldung/d/Windows98Machine.java

@@ -0,0 +1,15 @@
+package com.baeldung.d;
+
+public class Windows98Machine {
+
+  private final Keyboard keyboard;
+  private final Monitor monitor;
+
+  public Windows98Machine() {
+
+    monitor = new Monitor();
+    keyboard = new Keyboard();
+
+  }
+
+}

patterns/principles/solid/src/main/java/com/baeldung/d/Windows98MachineDI.java

@@ -0,0 +1,12 @@
+package com.baeldung.d;
+
+public class Windows98MachineDI {
+
+  private final Keyboard keyboard;
+  private final Monitor monitor;
+
+  public Windows98MachineDI(Keyboard keyboard, Monitor monitor) {
+    this.keyboard = keyboard;
+    this.monitor = monitor;
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/i/BearCarer.java

@@ -0,0 +1,12 @@
+package com.baeldung.i;
+
+public class BearCarer implements BearCleaner, BearFeeder {
+
+  public void washTheBear() {
+    //I think we missed a spot..
+  }
+
+  public void feedTheBear() {
+    //Tuna tuesdays..
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/i/BearCleaner.java

@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearCleaner {
+  void washTheBear();
+}

patterns/principles/solid/src/main/java/com/baeldung/i/BearFeeder.java

@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearFeeder {
+  void feedTheBear();
+}

patterns/principles/solid/src/main/java/com/baeldung/i/BearKeeper.java

@@ -0,0 +1,9 @@
+package com.baeldung.i;
+
+public interface BearKeeper {
+
+  void washTheBear();
+  void feedTheBear();
+  void petTheBear();
+
+}

patterns/principles/solid/src/main/java/com/baeldung/i/BearPetter.java

@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearPetter {
+  void petTheBear();
+}

patterns/principles/solid/src/main/java/com/baeldung/i/CrazyPerson.java

@@ -0,0 +1,8 @@
+package com.baeldung.i;
+
+public class CrazyPerson implements BearPetter {
+
+  public void petTheBear() {
+    //Good luck with that!
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/l/Car.java

@@ -0,0 +1,8 @@
+package com.baeldung.l;
+
+public interface Car {
+
+  void turnOnEngine();
+  void accelerate();
+
+}

patterns/principles/solid/src/main/java/com/baeldung/l/ElectricCar.java

@@ -0,0 +1,12 @@
+package com.baeldung.l;
+
+public class ElectricCar implements Car {
+
+  public void turnOnEngine() {
+    throw new AssertionError("I don't have an engine!");
+  }
+
+  public void accelerate() {
+    //this acceleration is crazy!
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/l/Engine.java

@@ -0,0 +1,13 @@
+package com.baeldung.l;
+
+public class Engine {
+
+  public void on(){
+    //vroom.
+  }
+
+  public void powerOn(int amount){
+    //do something
+  }
+
+}

patterns/principles/solid/src/main/java/com/baeldung/l/MotorCar.java

@@ -0,0 +1,18 @@
+package com.baeldung.l;
+
+public class MotorCar implements Car {
+
+  private Engine engine;
+
+  //Constructors, getters + setters
+
+  public void turnOnEngine() {
+    //turn on the engine!
+    engine.on();
+  }
+
+  public void accelerate() {
+    //move forward!
+    engine.powerOn(1000);
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/o/Guitar.java

@@ -0,0 +1,10 @@
+package com.baeldung.o;
+
+public class Guitar {
+
+  private String make;
+  private String model;
+  private int volume;
+
+  //Constructors, getters & setters
+}

patterns/principles/solid/src/main/java/com/baeldung/o/SuperCoolGuitarWithFlames.java

@@ -0,0 +1,9 @@
+package com.baeldung.o;
+
+public class SuperCoolGuitarWithFlames extends Guitar {
+
+  private String flameColour;
+
+  //constructor, getters + setters
+
+}

patterns/principles/solid/src/main/java/com/baeldung/s/BadBook.java

@@ -0,0 +1,27 @@
+package com.baeldung.s;
+
+public class BadBook {
+
+  private String name;
+  private String author;
+  private String text;
+
+  //constructor, getters and setters
+
+
+  //methods that directly relate to the book properties
+  public String replaceWordInText(String word){
+    return text.replaceAll(word, text);
+  }
+
+  public boolean isWordInText(String word){
+    return text.contains(word);
+  }
+
+  //methods for outputting text to console - should this really be here?
+  void printTextToConsole(){
+    //our code for formatting and printing the text
+  }
+
+
+}

patterns/principles/solid/src/main/java/com/baeldung/s/BookPrinter.java

@@ -0,0 +1,13 @@
+package com.baeldung.s;
+
+public class BookPrinter {
+
+  //methods for outputting text
+  void printTextToConsole(String text){
+    //our code for formatting and printing the text
+  }
+
+  void printTextToAnotherMedium(String text){
+    //code for writing to any other location..
+  }
+}

patterns/principles/solid/src/main/java/com/baeldung/s/GoodBook.java

@@ -0,0 +1,20 @@
+package com.baeldung.s;
+
+public class GoodBook {
+
+  private String name;
+  private String author;
+  private String text;
+
+  //constructor, getters and setters
+
+  //methods that directly relate to the book properties
+  public String replaceWordInText(String word){
+    return text.replaceAll(word, text);
+  }
+
+  public boolean isWordInText(String word){
+    return text.contains(word);
+  }
+
+}