soverby

package com.soverby.test;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.IntStream;

public class ThrottledExecutor {

soverby

package com.soverby.test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Semaphore;
import java.util.concurrent.locks.ReentrantLock;

public class AccessPool<T> {

soverby

package com.soverby.test;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.function.Consumer;
import java.util.function.Supplier;

import static java.lang.String.format;

soverby

import org.apache.http.client.config.RequestConfig;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ClientHttpPoolConfiguration {

soverby

// Example of a fully imperative approach to writing Java code...
public class FullyImperative {
 
    // @Inject
    private final ItemRepository itemRepository;
    // @Inject
    private final InventoryLocationRepostitory inventoryLocationRepostitory;

    // Find the first available InventoryLocation for a given item id. 
    public InventoryLocation itemByFirstAvailable(String itemId)

soverby

// Somewhere on the road from imperative to functional...
public class PartiallyImperative {
    // @Inject
    private ItemRepository itemRepository;
    // @Inject
    private InventoryLocationRepostitory;

    // Optionally return inventory location with available inventory for item with the given id
    public Optional<InventoryLocation> itemByFirstAvailable(String itemId) throws NotFoundException {

soverby

// And finally a functional example of the find location with non-zero inventory for item example
public class Functional {
  
    // @Inject
    private ItemRepository itemRepository;
    // @Inject
    private InventoryLocationRepostitory inventoryLocationRepostitory;

    // Monadic approach, composed behaviors
    // "The monad represents computations with a sequential structure: a monad defines what it means to chain operations together."

soverby

public class OptionalChaining {
    public static void main(String[] args) {
        OptionalChaining optionalChaining = new OptionalChaining();
        optionalChaining.happyPath();
        optionalChaining.nullInput();
        optionalChaining.thereBeNullsHereOne();
        optionalChaining.thereBeNullsHereTwo();
    }

    // Happy path with a pipeline that doesn't return nulls

soverby

public class OptionalChainingComposed {

    public static void main(String[] args) {
        OptionalChainingComposed optionalChaining = new OptionalChainingComposed();
        optionalChaining.happyPath();
        optionalChaining.nullInput();
    }

    public void happyPath() {
        nonNullPipeline("happyPath")

soverby

import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.Supplier;

public class JavaLambdaSyntax {

    private Consumer<String> stringConsumer;
    private Supplier<String> stringSupplier;
    private BiFunction<String, String, String> stringBiFunction;