# External Links

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/// info

Before, this page used to list links to external articles.

The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

     *
     * @param external
     *            If {@code true}, external access is allowed.
     * @return a {@link SchemaFactory} for W3C XML Schema
     */
    public static SchemaFactory newW3cXmlSchemaFactory(final boolean external) {
        final SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
        if (!external) {
            disableExternalResources(schemaFactory);

     *
     * @param external
     *            If {@code true}, external access is allowed.
     * @return A new instance of {@link DocumentBuilderFactory}.
     */
    public static DocumentBuilderFactory newInstance(final boolean external) {
        final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        if (!external) {
            try {

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

                }
            }
        }
        return result;
    }

    /**
     * Checks the URL to see if this repository refers to an external repository
     *
     * @param originalRepository
     * @return true if external.
     */
    static boolean isExternalRepo(ArtifactRepository originalRepository) {
        try {
            URL url = new URL(originalRepository.getUrl());

    This will (let's imagine) let the API user (some external developer) create an
    invoice.

    And this path operation will:

    * Send the invoice to the client.
    * Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event

.termy .linenos {
  display: none;
}

/* External links: detected by JS comparing origin to site origin
   JS sets data-external-link on links pointing outside the site
   Skip image links, .no-link-icon, and .announce-link */
a[data-external-link]:not(:has(img)):not(.no-link-icon):not(.announce-link) {
  /* For right to left languages */
  direction: ltr;
  display: inline-block;
}

            // create
            newInputs = inputs;
            newOutputs = outputs;
        }
    }

    /**
     * Gets the new input words.
     * Returns a defensive copy to prevent external modification.
     *
     * @return The new input words (defensive copy).
     */
    public String[] getNewInputs() {
        return newInputs == null ? null : newInputs.clone();
    }

    /**

            setFeature("http://apache.org/xml/features/disallow-doctype-decl", true)
            setFeature("http://xml.org/sax/features/external-general-entities", false)
            setFeature("http://xml.org/sax/features/external-parameter-entities", false)
            setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false)
            isExpandEntityReferences = false
            setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true)