Problem No: #6 How to use Aggregate Operations with Arrays.stream() [Part 1]?

Java 8 :: Streams and Lambda Expressions
/*
 * Problem No: #6
 * Problem Definition: How to use Aggregate Operations with Arrays.stream() [Part 1]?
 * 
 * Answer: By Using, 
 * >  java.util.Arrays: This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists. 
 *
 * >  IntStream java.util.Arrays.stream(int[] array): Returns a sequential IntStream with the specified array as its source. **array - the array, assumed to be unmodified during use.
 * 
 * > OptionalInt java.util.stream.IntStream.max()

OptionalInt max():
Returns an OptionalInt describing the maximum element of this stream, or an empty optional if this stream is empty. This is a special case of a reduction and is equivalent to: 

     return reduce(Integer::max);

This is a terminal operation.

Returns: 
an OptionalInt containing the maximum element of this stream, or an empty OptionalInt if the stream is empty.

> OptionalInt java.util.stream.IntStream.min()

OptionalInt min()
Returns an OptionalInt describing the minimum element of this stream, or an empty optional if this stream is empty. This is a special case of a reduction and is equivalent to: 

     return reduce(Integer::min);

This is a terminal operation.

Returns: 
an OptionalInt containing the minimum element of this stream, or an empty OptionalInt if the stream is empty 

> OptionalDouble java.util.stream.IntStream.average()

OptionalDouble average()
Returns an OptionalDouble describing the arithmetic mean of elements of this stream, or an empty optional if this stream is empty. This is a special case of a reduction. 
This is a terminal operation.

Returns: 
an OptionalDouble containing the average element of this stream, or an empty optional if the stream is empty 

> long java.util.stream.IntStream.count()

long count()
Returns the count of elements in this stream. This is a special case of a reduction and is equivalent to: 

     return mapToLong(e -> 1L).sum();

This is a terminal operation.

Returns: 
the count of elements in this stream 

> int java.util.stream.IntStream.sum()

int sum()
Returns the sum of elements in this stream. This is a special case of a reduction and is equivalent to: 

     return reduce(0, Integer::sum);

This is a terminal operation.

Returns: 
the sum of elements in this stream 

> int java.util.OptionalInt.getAsInt()

getAsInt
public int getAsInt()
If a value is present in this OptionalInt, returns the value, otherwise throws NoSuchElementException.

Returns: 
the value held by this OptionalInt 

Throws: 
NoSuchElementException - if there is no value present 


> double java.util.OptionalDouble.getAsDouble()

getAsDouble
public double getAsDouble()
If a value is present in this OptionalDouble, returns the value, otherwise throws NoSuchElementException.

Returns: 
the value held by this OptionalDouble 

Throws: 

NoSuchElementException - if there is no value present 

 * 
 **Same Operations can be applied with LongStream and DoubleStream
 *  
 * Program By: Mr.DIpak SOnar
 * Date : 25th Oct 2016
 */

import java.util.Arrays;

public class StreamWithArrayAggregateOpr {

public static void main(String[] args) {
int intArr[] = new int[7];

intArr[0] = 11;
intArr[1] = 21;
intArr[2] = 31;
intArr[3] = 41;
intArr[4] = 51;
intArr[5] = 61;
intArr[6] = 71;

// Arrays.stream(longArr).forEach(System.out::println); 
// To Print Integer Array using Stream

System.out.println("Arrays.stream(intArr).max().getAsInt(): "
+ Arrays.stream(intArr).max().getAsInt() );

System.out.println("Arrays.stream(intArr).min().getAsInt(): "
+ Arrays.stream(intArr).min().getAsInt() );

System.out.println("Arrays.stream(intArr).average().getAsDouble()"
+ Arrays.stream(intArr).average().getAsDouble() );

System.out.println("Arrays.stream(intArr).count(): "
+ Arrays.stream(intArr).count() );

System.out.println("Arrays.stream(intArr).sum(): "
+ Arrays.stream(intArr).sum() );

}
}