SoundCloudAPIConnector.java

package me.moodcat.soundcloud;

import javax.ws.rs.client.Client;

import lombok.SneakyThrows;
import org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder;

import java.net.URLEncoder;

/**
 * Connects to the SoundCloud API using its {@link #createClient()}.
 */
public class SoundCloudAPIConnector {

    /**
     * The charset that is used to encode urls.
     */
    protected static final String URI_CHARSET = "UTF-8";

    /**
     * The host-name able to be formatted with a sub-domain of SoundCloud.
     */
    protected static final String SOUNDCLOUD_HOST_FORMAT_STRING = "https://%ssoundcloud.com";

    /**
     * api.soundcloud.com takes care of all API calls.
     */
    protected static final String SOUNDCLOUD_API = String.format(
            SOUNDCLOUD_HOST_FORMAT_STRING, "api.");

    /**
     * soundcloud.com is the general host-name.
     */
    protected static final String SOUNDCLOUD_HOST = String.format(
            SOUNDCLOUD_HOST_FORMAT_STRING, "");

    /**
     * Our client-id in order to talk to SoundCloud.
     */
    protected static final String CLIENT_ID = "b45b1aa10f1ac2941910a7f0d10f8e28";
    
    protected SoundCloudAPIConnector() {
        // Only sub-classes may be instantiated.
    }

    /**
     * Obtain a HTTP-client to start a request.
     *
     * @return The HTTP-client.
     */
    protected Client createClient() {
        return ResteasyClientBuilder.newBuilder().build();
    }

    /**
     * Encode a String for URLs.
     * 
     * @param url
     *            string to be decoded
     * @return decoded string
     */
    @SneakyThrows
    protected static String encode(final String url) {
        return URLEncoder.encode(url, URI_CHARSET);
    }

    /**
     * Perform a Http request to the Soundcloud API.
     *
     * @param invocation
     *            Invocation that interacts with a {@link javax.ws.rs.client.WebTarget}.
     * @param <T>
     *            Type of response
     * @return return value of the request
     * @throws SoundCloudException
     *             If an error occurred
     */
    protected <T> T perform(final Invocation<T> invocation)
            throws SoundCloudException {
        return perform(SOUNDCLOUD_API, invocation);
    }

    /**
     * Perform a Http request to the Soundcloud API.
     *
     * @param host
     *            The host to send the request to
     * @param invocation
     *            Invocation that interacts with a {@link WebTarget}.
     * @param <T>
     *            Type of response
     * @return return value of the request
     * @throws SoundCloudException
     *             If an error occurred
     */
    protected <T> T perform(final String host, final Invocation<T> invocation)
            throws SoundCloudException {
        Client client = createClient();
        try {
            return invocation.perform(client.target(host));
        } catch (final Exception e) {
            throw new SoundCloudException(e.getMessage(), e);
        } finally {
            client.close();
        }
    }

}