Clases Heredadas E Interfaz Heredada De La API De Colecciones

Las versiones de Java anteriores a Java2 no contenían ningún marco de colecciones. Solo contenían algunas clases y una interfaz, que se usaban para almacenar objetos. Estos se denominan clases heredadas e interfaz heredada. Las clases heredadas se sincronizan a diferencia de las clases en el marco de la colección. Las clases heredadas son Dictionary, Hashtable, Properties, Stack y Vector. La interfaz heredada es la interfaz de enumeración.

Diccionario

El Diccionario es una clase abstracta. Asigna claves a valores y funciona de manera similar a un mapa. Cada clave y valor es un objeto en esta clase. Cada tecla se asigna a un valor máximo. Este mapeo nos permite recuperar el valor si se conoce la clave. La clase Dictionary se declara obsoleta en Java2 ya que es reemplazada por la clase Map. Contiene solo el constructor Dictionary() 

Métodos de la clase Diccionario

  • Elementos de enumeración(): Devuelve una enumeración que contiene los elementos del diccionario actual.
  • Object get(Objeto a): Devuelve el valor al que se asigna el objeto a. Si el objeto a no está presente en el diccionario, se devuelve un objeto nulo.
  • Boolean IsEmpty(): Comprueba si el diccionario actual contiene alguna clave. Si contiene al menos una clave, devuelve falso, de lo contrario, devuelve verdadero.
  • Claves de enumeración (): devuelve una enumeración que contiene las claves en el diccionario actual.
  • Poner objeto (clave de objeto, valor de objeto): asigna la clave de objeto al valor de objeto en el diccionario actual.
  • Eliminar objeto (Objeto a): elimina la clave especificada por el objeto a y su valor del diccionario actual y devuelve el valor asociado con a.
  • int Size(): Devuelve el número de entradas en el diccionario actual.

Tabla de picadillo

Hashtable almacena pares de valores clave en una tabla hash. Debemos especificar la clave y el valor que se asignará a esa clave. La clave tiene un hash y el código hash se utiliza como índice de la posición en la que se almacena el valor. El objeto de la clase Hashtable debe anular el método hashCode() y equals() de la clase Object. El método hashCode() se usa para convertir la clave a su código hash equivalente, y el método equals() se usa para comparar dos objetos. La tabla hash contiene 4 constructores.

  • Hashtable(): Cree una tabla hash vacía con la capacidad y el factor de carga predeterminados.
  • Hashtable(int cap): crea una tabla hash vacía con la capacidad inicial especificada por el límite y el factor de carga predeterminado.
  • Hashtable(int cap, float load): crea una tabla hash vacía con la capacidad inicial especificada por cap y el factor de carga especificado por load.
  • Hashtable(Map m): Crea una tabla hash cuyas asignaciones son las del mapa m

El factor de carga predeterminado es 0,75 y puede variar de 0,0 a 1,0. Además de los métodos de la clase de interfaz Mapa define los métodos.

Además de los métodos de la interfaz Map, la clase Hastable define algunos métodos:

  • void clear(): elimina todas las claves de la tabla hash.
  • Object clone(): crea un duplicado de la tabla hash actual.
  • boolean containsKey(Object a): Comprueba si la tabla hash contiene una clave especificada por un . Si se encuentra, devuelve verdadero, de lo contrario, devuelve falso.
  • boolean contains(Object a): comprueba si la tabla hash contiene alguna clave asignada al valor especificado por a. Si se encuentra, devuelve verdadero, de lo contrario, devuelve falso.
  • booleano contiene valor (objeto a): compruebe si la tabla hash contiene una o más claves asignadas al valor especificado por a y devuelve verdadero o falso según corresponda. Este método es similar al método contiene.
  • Elementos de enumeración (): devuelve una enumeración que contiene los valores de la tabla hash actual.
  • Object get(Objeto a): Devuelve el valor asociado a la clave especificada por un . Si no existe tal clave, se devuelve nulo.
  • boolean isEmpty(): Comprueba si la tabla hash está vacía. Devuelve verdadero si la tabla hash está vacía y devuelve falso si contiene al menos una clave.

El siguiente ejemplo ilustra el uso de Hashtable. Utiliza el ejemplo de las notas anotadas por el estudiante.

import java.util.*;
class HashtableEg {
    public static void main(String args[]) {
        Hashtable h = new Hastable();
        h.put("Ashish", new Integer(70));
        h.put("Sonali", new Integer(65));
        h.put("Soniya", new Integer(58));
        h.put("Akash", new Integer(80));
        h.put("Anuj", new Integer(78));
        Enumeration e = h.elements();
        while (e.hasMoreElements()) {
            System.out.println(e.nextElement());
        }
    }
}

Java

  • Guarde el archivo como HashtableEg.java
  • Compile el archivo usando javac HashtableEg.java
  • Ejecute el archivo usando java HashtableEg

Propiedades

La clase Propiedades amplía la clase Hashtable. La clase de propiedades representa un conjunto persistente de propiedades. Cada clave y su valor en la lista de propiedades es una cadena. También puede contener otra lista de propiedades como sus "predeterminados". Se buscará en la lista de propiedades predeterminada si la clave no está presente en la lista de propiedades actual. La clase de propiedades es utilizada por muchas otras clases de Java.

  • Propiedades (): crea una lista de propiedades vacía sin valores predeterminados.
  • Propiedades (Propiedades def): crea una lista de propiedades vacía con los valores predeterminados especificados por def.

La clase de propiedades contiene sus propios métodos además de los métodos que hereda de Hashtable.

  • String getProperty(String key): Devuelve el valor asociado con la clave especificada por key en la lista de propiedades actual.
  • String getProperty(String key, String prop): Devuelve el valor asociado con la clave en la lista de propiedades actual. Si key no está ni en la lista ni en la lista de propiedades predeterminadas, se devuelve prop.
  • lista vacía (PrintStream out): envía la lista de propiedades al flujo de salida por salida.
  • void list(PrintWriter str): envía la lista de propiedades al flujo de salida especificado por str.
  • carga vacía (InputStream in): ingrese una lista de propiedades del flujo de entrada especificado por in
  • Enumeración propertyNames(): Devuelve una enumeración de las claves en la lista de propiedades actual.
  • Object setProperty(String key, String val): llama al método hashtable put para asociar el valor especificado por val con la clave especificada por val.
  • void store(OutputStream out, String desc): escribe la lista de propiedades en la tabla de propiedades en el flujo de salida especificado por out.

Vector

La clase Vector implementa una matriz creciente de objetos. Se puede acceder a sus componentes utilizando un índice entero. Cada vector mantiene una capacidad y un incremento de capacidad. La capacidad siempre es mayor o igual que el tamaño del vector.

El siguiente constructor de clase vectorial como,

  • Vector(): crea un vector vacío. Su tamaño es 10 y el incremento de capacidad es 0.
  • Vector(Colección c): Crea un vector que contiene los elementos de la colección c. Se accede a los elementos en el orden devuelto por el iterador de la colección.
  • Vector(int cap): crea un vector vacío con la capacidad inicial especificada por cap y el incremento de capacidad 0.
  • Vector(int cap, int inc): crea un vector vacío con la capacidad inicial especificada por cap y el incremento de capacidad especificado por inc.

El siguiente programa ilustra el uso de la clase Vector.

import java.util.*;
class VectorEg {
    public static void main(String args[]) {
        Vector v = new Vector();
        v.add("First");
        int i = 1;
        v.add(new Integer(i));
        double d = 1.1;
        v.add(new Double(d));
        v.add("Second");
        i = 2;
        v.add(new Integer(i));
        d = 2.2;
        v.add(new Double(d));
        Enumeration e = v.elements();
        System.out.println("The elements of the vector are as follows:\n");
        while (e.hasMoreElements()) {
            System.out.println(e.nextElement());
        }
        System.out.println("\n");
        System.out.println("The Capacity of the vector is:" + v.capacity());
        System.out.println("The Size of the vector is:" + v.size());
        System.out.println("The Second element  of the vector is:" + v.elementAt(1));
        System.out.println("The First element  of the vector is:" + v.firstElement());
        System.out.println("The Last element  of the vector is:" + v.lastElement());
        v.removeElementAt(2);
        e = v.elements();
        System.out.println("\n The Vector after removing one of its elements is as follows:\n");
        while (e.hasMoreElements()) {
            System.out.println(e.nextElement());
        }
        System.out.println("\n");
    }
}

Java

  • Guarde el archivo como VectorEg.java
  • Compile el archivo usando javac VectorEg.java
  • Ejecute el archivo usando java VectorEg

Pila

La clase de pila representa una pila de objetos de tipo último en entrar, primero en salir y amplía la clase Vector. Contiene un único constructor, llamado Stack(), que crea una pila vacía. Contiene cinco métodos que permiten tratar un Vector como una pila.

  • booleano vacío (): comprueba si la pila actual está vacía.
  • Vistazo de objeto (): devuelve el objeto en la parte superior de la pila.
  • Object pop (): elimina el objeto en la parte superior de la pila.
  • Empuje de objeto (Objeto a): Empuje el objeto a a la parte superior de la pila
  • int search(Objeto a): Devuelve la posición del objeto en la pila. La posición comienza con 1.

Interfaz de enumeración

La interfaz de enumeración es la única interfaz heredada. Define métodos, que nos ayudan a enumerar los elementos en una colección de objetos. Esta interfaz ha sido suspendida por Iterator. Contiene solo 2 métodos como se muestra aquí:

  • boolean hasMoreElements(): Comprueba si la enumeración contiene más elementos. Si contiene más elementos, devuelve verdadero, de lo contrario, devuelve falso.
  • Object nextElement(): Devuelve el siguiente elemento de la enumeración. Si no hay más elementos para recuperar, arroja NoSuchElementException.

Resumen

La interfaz de colección está en la parte superior de la jerarquía. Nos permite trabajar con grupos de objetos. La interfaz List amplía la interfaz Collection y maneja secuencias. Las clases heredadas son Dictionary, Hashtable, Properties, Stack y vector. La interfaz heredada es la interfaz de enumeración.

Fuente: https://www.c-sharpcorner.com/article/legacy-classes-and-legacy-interface-of-collections-api/

#api 

What is GEEK

Buddha Community

Clases Heredadas E Interfaz Heredada De La API De Colecciones

Top 10 API Security Threats Every API Team Should Know

As more and more data is exposed via APIs either as API-first companies or for the explosion of single page apps/JAMStack, API security can no longer be an afterthought. The hard part about APIs is that it provides direct access to large amounts of data while bypassing browser precautions. Instead of worrying about SQL injection and XSS issues, you should be concerned about the bad actor who was able to paginate through all your customer records and their data.

Typical prevention mechanisms like Captchas and browser fingerprinting won’t work since APIs by design need to handle a very large number of API accesses even by a single customer. So where do you start? The first thing is to put yourself in the shoes of a hacker and then instrument your APIs to detect and block common attacks along with unknown unknowns for zero-day exploits. Some of these are on the OWASP Security API list, but not all.

Insecure pagination and resource limits

Most APIs provide access to resources that are lists of entities such as /users or /widgets. A client such as a browser would typically filter and paginate through this list to limit the number items returned to a client like so:

First Call: GET /items?skip=0&take=10 
Second Call: GET /items?skip=10&take=10

However, if that entity has any PII or other information, then a hacker could scrape that endpoint to get a dump of all entities in your database. This could be most dangerous if those entities accidently exposed PII or other sensitive information, but could also be dangerous in providing competitors or others with adoption and usage stats for your business or provide scammers with a way to get large email lists. See how Venmo data was scraped

A naive protection mechanism would be to check the take count and throw an error if greater than 100 or 1000. The problem with this is two-fold:

  1. For data APIs, legitimate customers may need to fetch and sync a large number of records such as via cron jobs. Artificially small pagination limits can force your API to be very chatty decreasing overall throughput. Max limits are to ensure memory and scalability requirements are met (and prevent certain DDoS attacks), not to guarantee security.
  2. This offers zero protection to a hacker that writes a simple script that sleeps a random delay between repeated accesses.
skip = 0
while True:    response = requests.post('https://api.acmeinc.com/widgets?take=10&skip=' + skip),                      headers={'Authorization': 'Bearer' + ' ' + sys.argv[1]})    print("Fetched 10 items")    sleep(randint(100,1000))    skip += 10

How to secure against pagination attacks

To secure against pagination attacks, you should track how many items of a single resource are accessed within a certain time period for each user or API key rather than just at the request level. By tracking API resource access at the user level, you can block a user or API key once they hit a threshold such as “touched 1,000,000 items in a one hour period”. This is dependent on your API use case and can even be dependent on their subscription with you. Like a Captcha, this can slow down the speed that a hacker can exploit your API, like a Captcha if they have to create a new user account manually to create a new API key.

Insecure API key generation

Most APIs are protected by some sort of API key or JWT (JSON Web Token). This provides a natural way to track and protect your API as API security tools can detect abnormal API behavior and block access to an API key automatically. However, hackers will want to outsmart these mechanisms by generating and using a large pool of API keys from a large number of users just like a web hacker would use a large pool of IP addresses to circumvent DDoS protection.

How to secure against API key pools

The easiest way to secure against these types of attacks is by requiring a human to sign up for your service and generate API keys. Bot traffic can be prevented with things like Captcha and 2-Factor Authentication. Unless there is a legitimate business case, new users who sign up for your service should not have the ability to generate API keys programmatically. Instead, only trusted customers should have the ability to generate API keys programmatically. Go one step further and ensure any anomaly detection for abnormal behavior is done at the user and account level, not just for each API key.

Accidental key exposure

APIs are used in a way that increases the probability credentials are leaked:

  1. APIs are expected to be accessed over indefinite time periods, which increases the probability that a hacker obtains a valid API key that’s not expired. You save that API key in a server environment variable and forget about it. This is a drastic contrast to a user logging into an interactive website where the session expires after a short duration.
  2. The consumer of an API has direct access to the credentials such as when debugging via Postman or CURL. It only takes a single developer to accidently copy/pastes the CURL command containing the API key into a public forum like in GitHub Issues or Stack Overflow.
  3. API keys are usually bearer tokens without requiring any other identifying information. APIs cannot leverage things like one-time use tokens or 2-factor authentication.

If a key is exposed due to user error, one may think you as the API provider has any blame. However, security is all about reducing surface area and risk. Treat your customer data as if it’s your own and help them by adding guards that prevent accidental key exposure.

How to prevent accidental key exposure

The easiest way to prevent key exposure is by leveraging two tokens rather than one. A refresh token is stored as an environment variable and can only be used to generate short lived access tokens. Unlike the refresh token, these short lived tokens can access the resources, but are time limited such as in hours or days.

The customer will store the refresh token with other API keys. Then your SDK will generate access tokens on SDK init or when the last access token expires. If a CURL command gets pasted into a GitHub issue, then a hacker would need to use it within hours reducing the attack vector (unless it was the actual refresh token which is low probability)

Exposure to DDoS attacks

APIs open up entirely new business models where customers can access your API platform programmatically. However, this can make DDoS protection tricky. Most DDoS protection is designed to absorb and reject a large number of requests from bad actors during DDoS attacks but still need to let the good ones through. This requires fingerprinting the HTTP requests to check against what looks like bot traffic. This is much harder for API products as all traffic looks like bot traffic and is not coming from a browser where things like cookies are present.

Stopping DDoS attacks

The magical part about APIs is almost every access requires an API Key. If a request doesn’t have an API key, you can automatically reject it which is lightweight on your servers (Ensure authentication is short circuited very early before later middleware like request JSON parsing). So then how do you handle authenticated requests? The easiest is to leverage rate limit counters for each API key such as to handle X requests per minute and reject those above the threshold with a 429 HTTP response. There are a variety of algorithms to do this such as leaky bucket and fixed window counters.

Incorrect server security

APIs are no different than web servers when it comes to good server hygiene. Data can be leaked due to misconfigured SSL certificate or allowing non-HTTPS traffic. For modern applications, there is very little reason to accept non-HTTPS requests, but a customer could mistakenly issue a non HTTP request from their application or CURL exposing the API key. APIs do not have the protection of a browser so things like HSTS or redirect to HTTPS offer no protection.

How to ensure proper SSL

Test your SSL implementation over at Qualys SSL Test or similar tool. You should also block all non-HTTP requests which can be done within your load balancer. You should also remove any HTTP headers scrub any error messages that leak implementation details. If your API is used only by your own apps or can only be accessed server-side, then review Authoritative guide to Cross-Origin Resource Sharing for REST APIs

Incorrect caching headers

APIs provide access to dynamic data that’s scoped to each API key. Any caching implementation should have the ability to scope to an API key to prevent cross-pollution. Even if you don’t cache anything in your infrastructure, you could expose your customers to security holes. If a customer with a proxy server was using multiple API keys such as one for development and one for production, then they could see cross-pollinated data.

#api management #api security #api best practices #api providers #security analytics #api management policies #api access tokens #api access #api security risks #api access keys

Autumn  Blick

Autumn Blick

1601381326

Public ASX100 APIs: The Essential List

We’ve conducted some initial research into the public APIs of the ASX100 because we regularly have conversations about what others are doing with their APIs and what best practices look like. Being able to point to good local examples and explain what is happening in Australia is a key part of this conversation.

Method

The method used for this initial research was to obtain a list of the ASX100 (as of 18 September 2020). Then work through each company looking at the following:

  1. Whether the company had a public API: this was found by googling “[company name] API” and “[company name] API developer” and “[company name] developer portal”. Sometimes the company’s website was navigated or searched.
  2. Some data points about the API were noted, such as the URL of the portal/documentation and the method they used to publish the API (portal, documentation, web page).
  3. Observations were recorded that piqued the interest of the researchers (you will find these below).
  4. Other notes were made to support future research.
  5. You will find a summary of the data in the infographic below.

Data

With regards to how the APIs are shared:

#api #api-development #api-analytics #apis #api-integration #api-testing #api-security #api-gateway

An API-First Approach For Designing Restful APIs | Hacker Noon

I’ve been working with Restful APIs for some time now and one thing that I love to do is to talk about APIs.

So, today I will show you how to build an API using the API-First approach and Design First with OpenAPI Specification.

First thing first, if you don’t know what’s an API-First approach means, it would be nice you stop reading this and check the blog post that I wrote to the Farfetchs blog where I explain everything that you need to know to start an API using API-First.

Preparing the ground

Before you get your hands dirty, let’s prepare the ground and understand the use case that will be developed.

Tools

If you desire to reproduce the examples that will be shown here, you will need some of those items below.

  • NodeJS
  • OpenAPI Specification
  • Text Editor (I’ll use VSCode)
  • Command Line

Use Case

To keep easy to understand, let’s use the Todo List App, it is a very common concept beyond the software development community.

#api #rest-api #openai #api-first-development #api-design #apis #restful-apis #restful-api

Marcelle  Smith

Marcelle Smith

1598083582

What Are Good Traits That Make Great API Product Managers

As more companies realize the benefits of an API-first mindset and treating their APIs as products, there is a growing need for good API product management practices to make a company’s API strategy a reality. However, API product management is a relatively new field with little established knowledge on what is API product management and what a PM should be doing to ensure their API platform is successful.

Many of the current practices of API product management have carried over from other products and platforms like web and mobile, but API products have their own unique set of challenges due to the way they are marketed and used by customers. While it would be rare for a consumer mobile app to have detailed developer docs and a developer relations team, you’ll find these items common among API product-focused companies. A second unique challenge is that APIs are very developer-centric and many times API PMs are engineers themselves. Yet, this can cause an API or developer program to lose empathy for what their customers actually want if good processes are not in place. Just because you’re an engineer, don’t assume your customers will want the same features and use cases that you want.

This guide lays out what is API product management and some of the things you should be doing to be a good product manager.

#api #analytics #apis #product management #api best practices #api platform #api adoption #product managers #api product #api metrics

Autumn  Blick

Autumn Blick

1602851580

54% of Developers Cite Lack of Documentation as the Top Obstacle to Consuming APIs

Recently, I worked with my team at Postman to field the 2020 State of the API survey and report. We’re insanely grateful to the folks who participated—more than 13,500 developers and other professionals took the survey, helping make this the largest and most comprehensive survey in the industry. (Seriously folks, thank you!) Curious what we learned? Here are a few insights in areas that you might find interesting:

API Reliability

Whether internal, external, or partner, APIs are perceived as reliable—more than half of respondents stated that APIs do not break, stop working, or materially change specification often enough to matter. Respondents choosing the “not often enough to matter” option here came in at 55.8% for internal APIs, 60.4% for external APIs, and 61.2% for partner APIs.

Obstacles to Producing APIs

When asked about the biggest obstacles to producing APIs, lack of time is by far the leading obstacle, with 52.3% of respondents listing it. Lack of knowledge (36.4%) and people (35.1%) were the next highest.

#api #rest-api #apis #api-first-development #api-report #api-documentation #api-reliability #hackernoon-top-story