Java - Join and Split Arrays and Collections

core-java/src/test/java/org/baeldung/java/CollectionsJoinAndSplitJUnitTest.java

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+package org.baeldung.java.collections;
+
+import java.util.ArrayList;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+
+//import java.util.AbstractSet;
+
+public class CollectionsJoinAndSplitJUnitTest {
+
+    public ArrayList<String> sauces = new ArrayList<String>();
+    public ArrayList<String> cheeses = new ArrayList<String>();
+    public ArrayList<String> vegetables = new ArrayList<String>();
+    
+    public ArrayList<ArrayList<String>> ingredients = new ArrayList<ArrayList<String>>();
+
+    public CollectionsJoinAndSplitJUnitTest() throws Exception {
+        //generate test data
+        whenGeneratingTestData_ShouldSucceed();
+    }
+
+    @Test
+    public void whenGeneratingTestData_ShouldSucceed() throws Exception {
+        sauces.clear();
+        sauces.add("Olive Oil");
+        sauces.add("Marinara");
+        
+        cheeses.clear();
+        cheeses.add("Mozarella");
+        cheeses.add("Feta");
+        cheeses.add("Parmesan");
+        
+        vegetables.clear();
+        vegetables.add("Olives");
+        vegetables.add("Spinach");
+        vegetables.add("Green Peppers");
+        
+        ingredients.clear();
+        ingredients.add(sauces);
+        ingredients.add(cheeses);
+        ingredients.add(vegetables);
+
+        Assert.assertTrue(sauces.size() == 2);
+        Assert.assertTrue(cheeses.size() == 3);
+        Assert.assertTrue(vegetables.size() == 3);
+        Assert.assertTrue(ingredients.size() == 3);
+    }
+        
+    @Test
+    public void givenThreeArrayLists_whenJoiningIntoOneArrayList_ShouldSucceed() throws Exception {
+        ArrayList<ArrayList<String>> toppings = new ArrayList<ArrayList<String>>();
+        
+        toppings.add(sauces);
+        toppings.add(cheeses);
+        toppings.add(vegetables);
+
+        Assert.assertTrue(toppings.size() == 3);
+        Assert.assertTrue(toppings.contains(sauces));
+        Assert.assertTrue(toppings.contains(cheeses));
+        Assert.assertTrue(toppings.contains(vegetables));
+    }
+    
+   @Test
+   public void givenOneArrayList_whenSplittingIntoTwoArrayLists_shouldSucceed() throws Exception {
+       ArrayList<ArrayList<String>> toppings = ingredients;
+       ArrayList<ArrayList<String>> removedToppings = new ArrayList<ArrayList<String>>(); 
+       
+       removedToppings.add(toppings.remove(toppings.indexOf(vegetables)));
+       
+       Assert.assertTrue(removedToppings.contains(vegetables));
+       Assert.assertTrue(removedToppings.size() == 1);
+       Assert.assertTrue(toppings.size() == 2);
+       Assert.assertTrue(toppings.contains(sauces));
+       Assert.assertTrue(toppings.contains(cheeses));
+   }
+}

core-java/src/test/java/org/baeldung/java/arrays/ArraysJoinAndSplitJUnitTest.java

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+package org.baeldung.java.arrays;
+
+import java.util.Arrays;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ArraysJoinAndSplitJUnitTest {
+    
+    //pizza toppings
+    private final String[] sauces = {"Marinara", "Olive Oil"};
+    private final String[] cheeses = {"Mozzarella", "Feta", "Parmesan"};
+    private final String[] vegetables = {"Olives", "Spinach", "Green Peppers"};
+    
+
+    @Test
+    public void givenThreeStringArrays_whenJoiningIntoOneStringArray_ShouldSucceed() throws Exception {
+        //create the destination array
+        String[] toppings = new String[sauces.length + cheeses.length + vegetables.length];
+        
+        //add the sauces
+        System.arraycopy(sauces, 0, toppings, 0, sauces.length);
+        int AddedSoFarCount = sauces.length;
+        
+        //add the cheeses
+        System.arraycopy(cheeses, 0, toppings, AddedSoFarCount, cheeses.length);
+        AddedSoFarCount += cheeses.length;
+
+        //add the vegetables
+        System.arraycopy(vegetables, 0, toppings, AddedSoFarCount, vegetables.length);
+        
+        //check the result
+        Assert.assertArrayEquals(toppings,
+          new String[] {"Marinara", "Olive Oil", "Mozzarella", "Feta",
+          "Parmesan", "Olives", "Spinach", "Green Peppers"} );
+    }
+   
+    
+    private final String[] customers = {"Jay", "Harry", "Ronnie", "Gary", "Ross"};
+    @Test
+    public void givenOneStringArray_whenSplittingInHalfBetweenTwoStringArrays_ShouldSucceed() throws Exception {
+        //split the orders in half, rounding up
+        int ordersHalved = (customers.length / 2) + (customers.length % 2);
+        
+        //divide the orders between two drivers
+        String[] driverOne = Arrays.copyOf(customers, ordersHalved);
+        String[] driverTwo = Arrays.copyOfRange(customers, ordersHalved, customers.length);
+        
+        //check ther result
+        Assert.assertArrayEquals(driverOne, new String[] {"Jay", "Harry", "Ronnie"} );
+        Assert.assertArrayEquals(driverTwo, new String[] {"Gary", "Ross"} );
+    }
+}

core-java/src/test/java/org/baeldung/java/collections/CollectionsJoinAndSplitJUnitTest.java

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+package org.baeldung.java.collections;
+
+import java.util.ArrayList;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+
+//import java.util.AbstractSet;
+
+public class CollectionsJoinAndSplitJUnitTest {
+
+    public ArrayList<String> sauces = new ArrayList<String>();
+    public ArrayList<String> cheeses = new ArrayList<String>();
+    public ArrayList<String> vegetables = new ArrayList<String>();
+    
+    public ArrayList<ArrayList<String>> ingredients = new ArrayList<ArrayList<String>>();
+
+    public CollectionsJoinAndSplitJUnitTest() throws Exception {
+        //generate test data
+        whenGeneratingTestData_ShouldSucceed();
+    }
+
+    @Test
+    public void whenGeneratingTestData_ShouldSucceed() throws Exception {
+        sauces.clear();
+        sauces.add("Olive Oil");
+        sauces.add("Marinara");
+        
+        cheeses.clear();
+        cheeses.add("Mozarella");
+        cheeses.add("Feta");
+        cheeses.add("Parmesan");
+        
+        vegetables.clear();
+        vegetables.add("Olives");
+        vegetables.add("Spinach");
+        vegetables.add("Green Peppers");
+        
+        ingredients.clear();
+        ingredients.add(sauces);
+        ingredients.add(cheeses);
+        ingredients.add(vegetables);
+
+        Assert.assertTrue(sauces.size() == 2);
+        Assert.assertTrue(cheeses.size() == 3);
+        Assert.assertTrue(vegetables.size() == 3);
+        Assert.assertTrue(ingredients.size() == 3);
+    }
+        
+    @Test
+    public void givenThreeArrayLists_whenJoiningIntoOneArrayList_ShouldSucceed() throws Exception {
+        ArrayList<ArrayList<String>> toppings = new ArrayList<ArrayList<String>>();
+        
+        toppings.add(sauces);
+        toppings.add(cheeses);
+        toppings.add(vegetables);
+
+        Assert.assertTrue(toppings.size() == 3);
+        Assert.assertTrue(toppings.contains(sauces));
+        Assert.assertTrue(toppings.contains(cheeses));
+        Assert.assertTrue(toppings.contains(vegetables));
+    }
+    
+   @Test
+   public void givenOneArrayList_whenSplittingIntoTwoArrayLists_shouldSucceed() throws Exception {
+       ArrayList<ArrayList<String>> toppings = ingredients;
+       ArrayList<ArrayList<String>> removedToppings = new ArrayList<ArrayList<String>>(); 
+       
+       removedToppings.add(toppings.remove(toppings.indexOf(vegetables)));
+       
+       Assert.assertTrue(removedToppings.contains(vegetables));
+       Assert.assertTrue(removedToppings.size() == 1);
+       Assert.assertTrue(toppings.size() == 2);
+       Assert.assertTrue(toppings.contains(sauces));
+       Assert.assertTrue(toppings.contains(cheeses));
+   }
+}