Java Used Pro

Priority Queue introduction and Java implementation

package com.java2novice.ds.queue;

public class PriorityQueueImpl

{

    SuppressWarnings("rawtypes")

    private Comparable[] pQueue;

    private int index;

 public PriorityQueueImpl(int capacity)

{

        pQueue = new Comparable[capacity];

 }

 public void insert(Comparable item )

{

        if(index == pQueue.length)

        {

            System.out.println("The priority queue is full!! can not insert.");

            return;

        }

        pQueue[index] = item;

        index++;

        System.out.println("Adding element: "+item);

    }

    SuppressWarnings("unchecked")

    public Comparable remove()

    {

        if(index == 0)

          {

            System.out.println("The priority queue is empty!! can not remove.");

            return null;

        }

        int maxIndex = 0;

        for (int i=1; i

           {

            if (pQueue[i].compareTo (pQueue[maxIndex]) > 0)

           {

                maxIndex = i;

            }

        }

        Comparable result = pQueue[maxIndex];

        System.out.println("removing: "+result);

        index--;

        pQueue[maxIndex] = pQueue[index];

        return result;

    }

    public static void main(String a[])

    {

        PriorityQueueImpl pqi = new PriorityQueueImpl(5);

        pqi.insert(34);

        pqi.insert(23);

        pqi.insert(5);

        pqi.insert(87);

        pqi.insert(32);

        pqi.remove();

        pqi.remove();

        pqi.remove();

        pqi.remove();

        pqi.remove();

    }

}

Average by properties

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

public class Main

{

 public static void main(String...args)

{

    double o = Food.menu.stream().collect(Collectors.averagingInt(Food::getCalories));

    System.out.println(o);

   }

}

enum Type { meat, fish, other }

class Food

{

  private final String name;

  private final boolean vegetarian;

  private final int calories;

  private final Type type;

 public Food(String name, boolean vegetarian, int calories, Type type)

 {

      this.name = name;

      this.vegetarian = vegetarian;

      this.calories = calories;

      this.type = type;

  }

            public String getName()

            {

      return name;

  }

             public boolean isVegetarian()

            {

      return vegetarian;

  }

             public int getCalories()

             {

      return calories;

  }

             public Type getType()

            {

      return type;

  }

  public String toString()

  {

      return name;

  }

  public static final List menu =

          Arrays.asList( new Food("pork", false, 1800, Type.meat),

                         new Food("beef", false, 7100, Type.meat),

                         new Food("chicken", false, 1400, Type.meat),

                         new Food("french fries", true, 1530, Type.other),

                         new Food("rice", true, 3510, Type.other),

                         new Food("season fruit", true, 1120, Type.other),

                         new Food("pizza", true, 5150, Type.other),

                         new Food("prawns", false, 1400, Type.fish),

                         new Food("salmon", false, 4150, Type.fish));

}