Keycloak client with support for externally provided AccessTokens

Example.java

String realm = "acme-dev";
String clientId = "some-app";
String serverUrl = "https://sso.acme.com/auth";
	
String accessToken = "Some token";
Keycloak keycloakWithAccessToken = Keycloak.getInstance(serverUrl, realm, clientId, accessToken);

String userId = "041d3213-1284-4331-958d-69611f9c8cbf";
System.out.println(keycloakWithAccessToken.realm(realm).users().get(userId).toRepresentation().getUsername());

Keycloak.java

/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.keycloak.admin.client;

import org.jboss.resteasy.client.jaxrs.ResteasyClient;
import org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder;
import org.jboss.resteasy.client.jaxrs.ResteasyWebTarget;
import org.keycloak.admin.client.resource.BearerAuthFilter;
import org.keycloak.admin.client.resource.RealmResource;
import org.keycloak.admin.client.resource.RealmsResource;
import org.keycloak.admin.client.resource.ServerInfoResource;
import org.keycloak.admin.client.token.TokenManager;

import java.net.URI;

import static org.keycloak.OAuth2Constants.PASSWORD;

/**
 * Provides a Keycloak client. By default, this implementation uses a {@link ResteasyClient RESTEasy client} with the
 * default {@link ResteasyClientBuilder} settings. To customize the underling client, use a {@link KeycloakBuilder} to
 * create a Keycloak client.
 *
 * @author rodrigo.sasaki@icarros.com.br
 * @see KeycloakBuilder
 */
public class Keycloak {
    private final Config config;
    private final TokenManager tokenManager;
    private final ResteasyWebTarget target;
    private final ResteasyClient client;

    Keycloak(String serverUrl, String realm, String username, String password, String clientId, String clientSecret, String grantType, ResteasyClient resteasyClient, String accessToken) {
    	
        config = new Config(serverUrl, realm, username, password, clientId, clientSecret, grantType);
        client = resteasyClient != null ? resteasyClient : new ResteasyClientBuilder().connectionPoolSize(10).build();

        tokenManager = new TokenManager(config, client);

        target = client.target(config.getServerUrl());

        if (accessToken == null) {
        	target.register(new BearerAuthFilter(tokenManager));
        } else {
        	target.register(new BearerAuthFilter(accessToken));
        }
    }

    public static Keycloak getInstance(String serverUrl, String realm, String username, String password, String clientId, String clientSecret) {
        return new Keycloak(serverUrl, realm, username, password, clientId, clientSecret, PASSWORD, null, null);
    }

    public static Keycloak getInstance(String serverUrl, String realm, String username, String password, String clientId) {
        return new Keycloak(serverUrl, realm, username, password, clientId, null, PASSWORD, null, null);
    }
    
    public static Keycloak getInstance(String serverUrl, String realm, String clientId, String accessTokenString) {
        return new Keycloak(serverUrl, realm, null, null, clientId, null, PASSWORD, null, accessTokenString);
    }

    public RealmsResource realms() {
        return target.proxy(RealmsResource.class);
    }

    public RealmResource realm(String realmName) {
        return realms().realm(realmName);
    }

    public ServerInfoResource serverInfo() {
        return target.proxy(ServerInfoResource.class);
    }

    public TokenManager tokenManager() {
        return tokenManager;
    }

    /**
     * Create a secure proxy based on an absolute URI.
     * All set up with appropriate token
     *
     * @param proxyClass
     * @param absoluteURI
     * @param <T>
     * @return
     */
    public <T> T proxy(Class<T> proxyClass, URI absoluteURI) {
        return client.target(absoluteURI).register(new BearerAuthFilter(tokenManager)).proxy(proxyClass);
    }

    /**
     * Closes the underlying client. After calling this method, this <code>Keycloak</code> instance cannot be reused.
     */
    public void close() {
        client.close();
    }
}