Fixed concurrency problems
[nonrtric.git] / policy-agent / src / test / java / org / oransc / policyagent / ApplicationTest.java
index d78155d..4ea6ff9 100644 (file)
 package org.oransc.policyagent;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.Assert.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.awaitility.Awaitility.await;
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
-import com.google.gson.reflect.TypeToken;
-
-import java.net.URL;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParser;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Vector;
+import java.util.concurrent.atomic.AtomicInteger;
 
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
-import org.oransc.policyagent.clients.A1Client;
 import org.oransc.policyagent.configuration.ApplicationConfig;
 import org.oransc.policyagent.configuration.ImmutableRicConfig;
 import org.oransc.policyagent.configuration.RicConfig;
-import org.oransc.policyagent.controllers.ImmutableServiceRegistrationInfo;
-import org.oransc.policyagent.controllers.ImmutableServiceStatus;
+import org.oransc.policyagent.controllers.PolicyInfo;
 import org.oransc.policyagent.controllers.ServiceRegistrationInfo;
 import org.oransc.policyagent.controllers.ServiceStatus;
 import org.oransc.policyagent.exceptions.ServiceException;
 import org.oransc.policyagent.repository.ImmutablePolicy;
 import org.oransc.policyagent.repository.ImmutablePolicyType;
+import org.oransc.policyagent.repository.Lock.LockType;
 import org.oransc.policyagent.repository.Policies;
 import org.oransc.policyagent.repository.Policy;
 import org.oransc.policyagent.repository.PolicyType;
 import org.oransc.policyagent.repository.PolicyTypes;
 import org.oransc.policyagent.repository.Ric;
+import org.oransc.policyagent.repository.Ric.RicState;
 import org.oransc.policyagent.repository.Rics;
+import org.oransc.policyagent.repository.Services;
+import org.oransc.policyagent.tasks.RepositorySupervision;
 import org.oransc.policyagent.utils.MockA1Client;
+import org.oransc.policyagent.utils.MockA1ClientFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
@@ -59,9 +69,16 @@ import org.springframework.boot.test.context.TestConfiguration;
 import org.springframework.boot.web.server.LocalServerPort;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.HttpStatus.Series;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.web.client.ResponseErrorHandler;
 import org.springframework.web.client.RestTemplate;
 
 @ExtendWith(SpringExtension.class)
@@ -79,15 +96,23 @@ public class ApplicationTest {
     @Autowired
     private PolicyTypes policyTypes;
 
+    @Autowired
+    MockA1ClientFactory a1ClientFactory;
+
+    @Autowired
+    RepositorySupervision supervision;
+
+    @Autowired
+    Services services;
+
     private static Gson gson = new GsonBuilder() //
-        .serializeNulls() //
-        .create(); //
+            .serializeNulls() //
+            .create(); //
 
     public static class MockApplicationConfig extends ApplicationConfig {
         @Override
-        protected String getLocalConfigurationFilePath() {
-            URL url = MockApplicationConfig.class.getClassLoader().getResource("test_application_configuration.json");
-            return url.getFile();
+        public String getLocalConfigurationFilePath() {
+            return ""; // No config file loaded for the test
         }
     }
 
@@ -96,8 +121,6 @@ public class ApplicationTest {
      */
     @TestConfiguration
     static class TestBeanFactory {
-        private final Rics rics = new Rics();
-        private final Policies policies = new Policies();
         private final PolicyTypes policyTypes = new PolicyTypes();
 
         @Bean
@@ -106,24 +129,14 @@ public class ApplicationTest {
         }
 
         @Bean
-        A1Client getA1Client() {
-            return new MockA1Client(this.policyTypes);
-        }
-
-        @Bean
-        public Policies getPolicies() {
-            return this.policies;
+        MockA1ClientFactory getA1ClientFactory() {
+            return new MockA1ClientFactory(this.policyTypes);
         }
 
         @Bean
         public PolicyTypes getPolicyTypes() {
             return this.policyTypes;
         }
-
-        @Bean
-        public Rics getRics() {
-            return this.rics;
-        }
     }
 
     @LocalServerPort
@@ -131,102 +144,148 @@ public class ApplicationTest {
 
     private final RestTemplate restTemplate = new RestTemplate();
 
-    private void reset() {
+    public class RestTemplateResponseErrorHandler implements ResponseErrorHandler {
+
+        @Override
+        public boolean hasError(ClientHttpResponse httpResponse) throws IOException {
+            return (httpResponse.getStatusCode().series() == Series.CLIENT_ERROR
+                    || httpResponse.getStatusCode().series() == Series.SERVER_ERROR);
+        }
+
+        @Override
+        public void handleError(ClientHttpResponse httpResponse) throws IOException {
+            System.out.println("Error " + httpResponse.toString());
+        }
+    }
+
+    private void setRestErrorhandler() {
+        restTemplate.setErrorHandler(new RestTemplateResponseErrorHandler());
+    }
+
+    @BeforeEach
+    public void reset() {
         rics.clear();
         policies.clear();
         policyTypes.clear();
-        assertThat(policies.size()).isEqualTo(0);
+        services.clear();
+    }
+
+    @AfterEach
+    public void verifyNoRicLocks() {
+        for (Ric ric : this.rics.getRics()) {
+            ric.getLock().lockBlocking(LockType.EXCLUSIVE);
+            ric.getLock().unlock();
+            assertThat(ric.getLock().getLockCounter()).isEqualTo(0);
+            assertThat(ric.getState()).isEqualTo(Ric.RicState.IDLE);
+        }
     }
 
     @Test
     public void testGetRics() throws Exception {
-        reset();
         addRic("kista_1");
         String url = baseUrl() + "/rics";
         String rsp = this.restTemplate.getForObject(url, String.class);
         System.out.println(rsp);
         assertThat(rsp).contains("kista_1");
 
-        url = baseUrl() + "/rics?policyType=ANR";
+        url = baseUrl() + "/rics?policyType=STD_PolicyModelUnconstrained_0.2.0";
         rsp = this.restTemplate.getForObject(url, String.class);
         assertThat(rsp).isEqualTo("[]");
     }
 
     @Test
-    public void testGetRic() throws Exception {
-        reset();
-        String url = baseUrl() + "/ric?managedElementId=kista_1";
+    public void testRecovery() throws Exception {
+        addRic("ric").setState(Ric.RicState.UNDEFINED);
+        String ricName = "ric";
+        Policy policy2 = addPolicy("policyId2", "typeName", "service", ricName);
+
+        getA1Client(ricName).putPolicy(policy2); // put it in the RIC
+        policies.remove(policy2); // Remove it from the repo -> should be deleted in the RIC
+
+        String policyId = "policyId";
+        Policy policy = addPolicy(policyId, "typeName", "service", ricName); // This should be created in the RIC
+        supervision.checkAllRics(); // The created policy should be put in the RIC
+        await().untilAsserted(() -> RicState.SYNCHRONIZING.equals(rics.getRic(ricName).getState()));
+        await().untilAsserted(() -> RicState.IDLE.equals(rics.getRic(ricName).getState()));
+
+        Policies ricPolicies = getA1Client(ricName).getPolicies();
+        assertThat(ricPolicies.size()).isEqualTo(1);
+        Policy ricPolicy = ricPolicies.get(policyId);
+        assertThat(ricPolicy.json()).isEqualTo(policy.json());
+    }
+
+    @Test
+    public void testGetRicForManagedElement_thenReturnCorrectRic() throws Exception {
+        addRic("notCorrectRic1");
+        addRic("notCorrectRic2");
+        addRic("notCorrectRic3");
+        addRic("notCorrectRic4");
+        addRic("notCorrectRic5");
+        addRic("notCorrectRic6");
+
+        String ricName = "ric1";
+        Ric ric = addRic(ricName);
+        String managedElementId = "kista_1";
+        ric.addManagedElement(managedElementId);
+
+        String url = baseUrl() + "/ric?managedElementId=" + managedElementId;
         String rsp = this.restTemplate.getForObject(url, String.class);
-        System.out.println(rsp);
-        assertThat(rsp).isEqualTo("ric1");
+
+        assertThat(rsp).isEqualTo(ricName);
+    }
+
+    @Test
+    public void testGetRicForManagedElementThatDoesNotExist() throws Exception {
+        this.setRestErrorhandler();
+        String url = baseUrl() + "/ric?managedElementId=kista_1";
+        ResponseEntity<String> entity = this.restTemplate.getForEntity(url, String.class);
+        assertThat(entity.getStatusCode().equals(HttpStatus.NOT_FOUND));
     }
 
     @Test
     public void testPutPolicy() throws Exception {
-        putService("service1");
+        String serviceName = "service1";
+        String ricName = "ric1";
+        String policyTypeName = "type1";
+        String policyInstanceId = "instance1";
 
-        String url = baseUrl() + "/policy?type=type1&instance=instance1&ric=ric1&service=service1";
-        String json = "{}";
-        addPolicyType("type1", "ric1");
-        this.rics.getRic("ric1").setState(Ric.RicState.IDLE);
+        putService(serviceName);
+        addPolicyType(policyTypeName, ricName);
 
-        this.restTemplate.put(url, json);
+        String url = baseUrl() + "/policy?type=" + policyTypeName + "&instance=" + policyInstanceId + "&ric=" + ricName
+                + "&service=" + serviceName;
+        final String json = jsonString();
+        this.rics.getRic(ricName).setState(Ric.RicState.IDLE);
 
-        Policy policy = policies.getPolicy("instance1");
+        this.restTemplate.put(url, createJsonHttpEntity(json));
 
+        Policy policy = policies.getPolicy(policyInstanceId);
         assertThat(policy).isNotNull();
-        assertThat(policy.id()).isEqualTo("instance1");
-        assertThat(policy.ownerServiceName()).isEqualTo("service1");
+        assertThat(policy.id()).isEqualTo(policyInstanceId);
+        assertThat(policy.ownerServiceName()).isEqualTo(serviceName);
+        assertThat(policy.ric().name()).isEqualTo("ric1");
 
         url = baseUrl() + "/policies";
         String rsp = this.restTemplate.getForObject(url, String.class);
-        System.out.println(rsp);
-    }
+        assertThat(rsp.contains(policyInstanceId)).isTrue();
 
-    private PolicyType addPolicyType(String policyTypeName, String ricName) {
-        PolicyType type = ImmutablePolicyType.builder() //
-            .name(policyTypeName) //
-            .schema("{\"title\":\"" + policyTypeName + "\"}") //
-            .build();
-
-        policyTypes.put(type);
-        addRic(ricName).addSupportedPolicyType(type);
-        return type;
-    }
-
-    private Ric addRic(String ricName) {
-        if (rics.get(ricName) != null) {
-            return rics.get(ricName);
-        }
-        Vector<String> mes = new Vector<>();
-        RicConfig conf = ImmutableRicConfig.builder() //
-            .name(ricName) //
-            .baseUrl("baseUrl") //
-            .managedElementIds(mes) //
-            .build();
-        Ric ric = new Ric(conf);
-        this.rics.put(ric);
-        return ric;
     }
 
-    private Policy addPolicy(String id, String typeName, String service, String ric) throws ServiceException {
-        addRic(ric);
-        Policy p = ImmutablePolicy.builder().id(id) //
-            .json("{}") //
-            .ownerServiceName(service) //
-            .ric(rics.getRic(ric)) //
-            .type(addPolicyType(typeName, ric)) //
-            .lastModified("lastModified").build();
-        policies.put(p);
-        return p;
-    }
-
-    private Policy addPolicy(String id, String typeName, String service) throws ServiceException {
-        return addPolicy(id, typeName, service, "ric");
-    }
+    @Test
+    public void testRefuseToUpdatePolicy() throws Exception {
+        // Test that only the json can be changed for a already created policy
+        // In this case service is attempted to be changed
+        this.addRic("ric1");
+        this.addRic("ricXXX");
+
+        this.addPolicy("instance1", "type1", "service1", "ric1");
+        this.setRestErrorhandler();
+        String urlWrongRic = baseUrl() + "/policy?type=type1&instance=instance1&ric=ricXXX&service=service1";
+        ResponseEntity<String> entity = this.putForEntity(urlWrongRic, jsonString());
+        assertThat(entity.getStatusCode().equals(HttpStatus.METHOD_NOT_ALLOWED));
 
-    private String baseUrl() {
-        return "http://localhost:" + port;
+        Policy policy = policies.getPolicy("instance1");
+        assertThat(policy.ric().name()).isEqualTo("ric1"); // Not changed
     }
 
     @Test
@@ -246,10 +305,8 @@ public class ApplicationTest {
 
     @Test
     public void testDeletePolicy() throws Exception {
-        reset();
         String url = baseUrl() + "/policy?instance=id";
-        Policy policy = addPolicy("id", "typeName", "service1", "ric1");
-        policy.ric().setState(Ric.RicState.IDLE);
+        addPolicy("id", "typeName", "service1", "ric1");
         assertThat(policies.size()).isEqualTo(1);
 
         this.restTemplate.delete(url);
@@ -257,17 +314,8 @@ public class ApplicationTest {
         assertThat(policies.size()).isEqualTo(0);
     }
 
-    private static <T> List<T> parseList(String json, Class<T> clazz) {
-        if (null == json) {
-            return null;
-        }
-        return gson.fromJson(json, new TypeToken<T>() {}.getType());
-
-    }
-
     @Test
     public void testGetPolicySchemas() throws Exception {
-        reset();
         addPolicyType("type1", "ric1");
         addPolicyType("type2", "ric2");
 
@@ -275,22 +323,20 @@ public class ApplicationTest {
         String rsp = this.restTemplate.getForObject(url, String.class);
         System.out.println("*** " + rsp);
         assertThat(rsp).contains("type1");
-        assertThat(rsp).contains("type2");
-        assertThat(rsp).contains("title");
+        assertThat(rsp).contains("[{\"title\":\"type2\"}");
 
-        List<String> info = parseList(rsp, String.class);
-        assertEquals(2, info.size());
+        List<String> info = parseSchemas(rsp);
+        assertThat(info.size()).isEqualTo(2);
 
         url = baseUrl() + "/policy_schemas?ric=ric1";
         rsp = this.restTemplate.getForObject(url, String.class);
         assertThat(rsp).contains("type1");
-        info = parseList(rsp, String.class);
-        assertEquals(1, info.size());
+        info = parseSchemas(rsp);
+        assertThat(info.size()).isEqualTo(1);
     }
 
     @Test
     public void testGetPolicySchema() throws Exception {
-        reset();
         addPolicyType("type1", "ric1");
         addPolicyType("type2", "ric2");
 
@@ -303,7 +349,6 @@ public class ApplicationTest {
 
     @Test
     public void testGetPolicyTypes() throws Exception {
-        reset();
         addPolicyType("type1", "ric1");
         addPolicyType("type2", "ric2");
 
@@ -318,14 +363,19 @@ public class ApplicationTest {
 
     @Test
     public void testGetPolicies() throws Exception {
+        reset();
         String url = baseUrl() + "/policies";
         addPolicy("id1", "type1", "service1");
-        addPolicy("id2", "type2", "service2");
 
         String rsp = this.restTemplate.getForObject(url, String.class);
         System.out.println(rsp);
-        assertThat(rsp).contains("id1");
-        assertThat(rsp).contains("id2");
+        List<PolicyInfo> info = parseList(rsp, PolicyInfo.class);
+        assertThat(info).size().isEqualTo(1);
+        PolicyInfo policyInfo = info.get(0);
+        assert (policyInfo.validate());
+        assertThat(policyInfo.id).isEqualTo("id1");
+        assertThat(policyInfo.type).isEqualTo("type1");
+        assertThat(policyInfo.service).isEqualTo("service1");
     }
 
     @Test
@@ -339,48 +389,212 @@ public class ApplicationTest {
         System.out.println(rsp);
         assertThat(rsp).contains("id1");
         assertThat(rsp).contains("id2");
-        assertFalse(rsp.contains("id3"));
+        assertThat(rsp.contains("id3")).isFalse();
 
         url = baseUrl() + "/policies?type=type1&service=service2";
         rsp = this.restTemplate.getForObject(url, String.class);
         System.out.println(rsp);
-        assertFalse(rsp.contains("id1"));
+        assertThat(rsp.contains("id1")).isFalse();
         assertThat(rsp).contains("id2");
-        assertFalse(rsp.contains("id3"));
+        assertThat(rsp.contains("id3")).isFalse();
+    }
+
+    @Test
+    public void testPutAndGetService() throws Exception {
+        // PUT
+        putService("name");
+
+        // GET
+        String url = baseUrl() + "/services?serviceName=name";
+        String rsp = this.restTemplate.getForObject(url, String.class);
+        List<ServiceStatus> info = parseList(rsp, ServiceStatus.class);
+        assertThat(info.size()).isEqualTo(1);
+        ServiceStatus status = info.iterator().next();
+        assertThat(status.keepAliveIntervalSeconds).isEqualTo(1);
+        assertThat(status.serviceName).isEqualTo("name");
+
+        // GET (all)
+        url = baseUrl() + "/services";
+        rsp = this.restTemplate.getForObject(url, String.class);
+        assertThat(rsp.contains("name")).isTrue();
+        System.out.println(rsp);
+
+        // Keep alive
+        url = baseUrl() + "/services/keepalive?name=name";
+        ResponseEntity<String> entity = this.restTemplate.postForEntity(url, null, String.class);
+        assertThat(entity.getStatusCode().equals(HttpStatus.OK));
+
+        // DELETE
+        assertThat(services.size()).isEqualTo(1);
+        url = baseUrl() + "/services?name=name";
+        this.restTemplate.delete(url);
+        assertThat(services.size()).isEqualTo(0);
+
+        // Keep alive, no registerred service
+        url = baseUrl() + "/services/keepalive?name=name";
+        setRestErrorhandler();
+        entity = this.restTemplate.postForEntity(url, null, String.class);
+        assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
+    }
+
+    @Test
+    public void testGetPolicyStatus() throws Exception {
+        addPolicy("id", "typeName", "service1", "ric1");
+        assertThat(policies.size()).isEqualTo(1);
+
+        String url = baseUrl() + "/policy_status?instance=id";
+        String rsp = this.restTemplate.getForObject(url, String.class);
+        assertThat(rsp.equals("OK")).isTrue();
+    }
+
+    private Policy addPolicy(String id, String typeName, String service, String ric) throws ServiceException {
+        addRic(ric);
+        Policy p = ImmutablePolicy.builder().id(id) //
+                .json(jsonString()) //
+                .ownerServiceName(service) //
+                .ric(rics.getRic(ric)) //
+                .type(addPolicyType(typeName, ric)) //
+                .lastModified("lastModified").build();
+        policies.put(p);
+        return p;
+    }
+
+    private Policy addPolicy(String id, String typeName, String service) throws ServiceException {
+        return addPolicy(id, typeName, service, "ric");
     }
 
     private String createServiceJson(String name) {
-        ServiceRegistrationInfo service = ImmutableServiceRegistrationInfo.builder() //
-            .keepAliveInterval(1) //
-            .name(name) //
-            .callbackUrl("callbackUrl") //
-            .build();
+        ServiceRegistrationInfo service = new ServiceRegistrationInfo(name, 1, "callbackUrl");
+
         String json = gson.toJson(service);
         return json;
     }
 
     private void putService(String name) {
         String url = baseUrl() + "/service";
-        this.restTemplate.put(url, createServiceJson(name));
+        HttpEntity<String> entity = createJsonHttpEntity(createServiceJson(name));
+        this.restTemplate.put(url, entity);
+    }
+
+    private String baseUrl() {
+        return "http://localhost:" + port;
+    }
+
+    private String jsonString() {
+        return "{\n  \"servingCellNrcgi\": \"1\"\n }";
+    }
+
+    private static class ConcurrencyTestRunnable implements Runnable {
+        private final RestTemplate restTemplate = new RestTemplate();
+        private final String baseUrl;
+        static AtomicInteger nextCount = new AtomicInteger(0);
+        private final int count;
+        private final RepositorySupervision supervision;
+
+        ConcurrencyTestRunnable(String baseUrl, RepositorySupervision supervision) {
+            this.baseUrl = baseUrl;
+            this.count = nextCount.incrementAndGet();
+            this.supervision = supervision;
+        }
+
+        public void run() {
+            for (int i = 0; i < 100; ++i) {
+                if (i % 10 == 0) {
+                    this.supervision.checkAllRics();
+                }
+                String name = "policy:" + count + ":" + i;
+                putPolicy(name);
+                deletePolicy(name);
+            }
+        }
+
+        private void putPolicy(String name) {
+            String putUrl = baseUrl + "/policy?type=type1&instance=" + name + "&ric=ric1&service=service1";
+            this.restTemplate.put(putUrl, createJsonHttpEntity("{}"));
+        }
+
+        private void deletePolicy(String name) {
+            String deleteUrl = baseUrl + "/policy?instance=" + name;
+            this.restTemplate.delete(deleteUrl);
+        }
     }
 
     @Test
-    public void testPutAndGetService() throws Exception {
-        putService("name");
+    public void testConcurrency() throws Exception {
+        final Instant startTime = Instant.now();
+        List<Thread> threads = new ArrayList<>();
+        addRic("ric1");
+        addPolicyType("type1", "ric1");
 
-        String url = baseUrl() + "/service?name=name";
-        String rsp = this.restTemplate.getForObject(url, String.class);
-        ServiceStatus status = gson.fromJson(rsp, ImmutableServiceStatus.class);
-        assertThat(status.keepAliveInterval() == 1);
-        assertThat(status.name().equals("name"));
+        for (int i = 0; i < 100; ++i) {
+            Thread t = new Thread(new ConcurrencyTestRunnable(baseUrl(), this.supervision), "TestThread_" + i);
+            t.start();
+            threads.add(t);
+        }
+        for (Thread t : threads) {
+            t.join();
+        }
+        assertThat(policies.size()).isEqualTo(0);
+        System.out.println("Concurrency test took " + Duration.between(startTime, Instant.now()));
+    }
 
-        url = baseUrl() + "/services";
-        rsp = this.restTemplate.getForObject(url, String.class);
-        assertThat(rsp.contains("name"));
-        System.out.println(rsp);
+    private MockA1Client getA1Client(String ricName) throws ServiceException {
+        return a1ClientFactory.getOrCreateA1Client(ricName);
+    }
 
-        url = baseUrl() + "/service/ping";
-        this.restTemplate.put(url, "name");
+    private PolicyType addPolicyType(String policyTypeName, String ricName) {
+        PolicyType type = ImmutablePolicyType.builder() //
+                .name(policyTypeName) //
+                .schema("{\"title\":\"" + policyTypeName + "\"}") //
+                .build();
+
+        policyTypes.put(type);
+        addRic(ricName).addSupportedPolicyType(type);
+        return type;
     }
 
+    private Ric addRic(String ricName) {
+        if (rics.get(ricName) != null) {
+            return rics.get(ricName);
+        }
+        Vector<String> mes = new Vector<>();
+        RicConfig conf = ImmutableRicConfig.builder() //
+                .name(ricName) //
+                .baseUrl(ricName) //
+                .managedElementIds(mes) //
+                .build();
+        Ric ric = new Ric(conf);
+        ric.setState(Ric.RicState.IDLE);
+        this.rics.put(ric);
+        return ric;
+    }
+
+    private static HttpEntity<String> createJsonHttpEntity(String content) {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_JSON);
+        return new HttpEntity<String>(content, headers);
+    }
+
+    private ResponseEntity<String> putForEntity(String url, String jsonBody) {
+        return restTemplate.exchange(url, HttpMethod.PUT, createJsonHttpEntity(jsonBody), String.class);
+    }
+
+    private static <T> List<T> parseList(String jsonString, Class<T> clazz) {
+        List<T> result = new ArrayList<>();
+        JsonArray jsonArr = JsonParser.parseString(jsonString).getAsJsonArray();
+        for (JsonElement jsonElement : jsonArr) {
+            T o = gson.fromJson(jsonElement.toString(), clazz);
+            result.add(o);
+        }
+        return result;
+    }
+
+    private static List<String> parseSchemas(String jsonString) {
+        JsonArray arrayOfSchema = JsonParser.parseString(jsonString).getAsJsonArray();
+        List<String> result = new ArrayList<>();
+        for (JsonElement schemaObject : arrayOfSchema) {
+            result.add(schemaObject.toString());
+        }
+        return result;
+    }
 }