Prepare for java 11

final changes for java11 groovy compatibility
removed unnecessary dependencies and cleaned up poms
added missing jaxws-api dependency to pom.xml
java8 profile is now active by default in parent pom
update beans to have RemoteResource annotation
always use the compiler plugin from parent pom
Update external task timeout to longer value to hold lock
update remote resource annotation to match catalog db client
add remote resource annotation to bean for bowman
completely remove bowman from requests db client

Issue-ID: SO-2059
Signed-off-by: Benjamin, Max (mb388a) <mb388a@att.com>
Change-Id: If6f0df36e8077ccd703abce9f64290daed63955b

4 files changed, 119 insertions, 200 deletions

diff --git a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/InfraRequests.java b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/InfraRequests.java
index cf6cf687b0..cc721d38b6 100644
--- a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/InfraRequests.java
+++ b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/InfraRequests.java
@@ -40,8 +40,6 @@ import javax.persistence.TemporalType;
 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.onap.so.requestsdb.TimestampXMLAdapter;
-import uk.co.blackpepper.bowman.annotation.LinkedResource;
-import uk.co.blackpepper.bowman.annotation.ResourceId;
 
 @MappedSuperclass
 public abstract class InfraRequests implements java.io.Serializable {
@@ -164,7 +162,6 @@ public abstract class InfraRequests implements java.io.Serializable {
     @JoinColumn(name = "SO_REQUEST_ID", referencedColumnName = "REQUEST_ID", updatable = false)
     private List<CloudApiRequests> cloudApiRequests = new ArrayList<>();
 
-    @ResourceId
     public URI getRequestURI() {
         return URI.create(this.requestId);
     }
@@ -443,7 +440,6 @@ public abstract class InfraRequests implements java.io.Serializable {
         return requestAction;
     }
 
-    @LinkedResource
     public List<CloudApiRequests> getCloudApiRequests() {
         return cloudApiRequests;
     }
diff --git a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/OperationalEnvServiceModelStatus.java b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/OperationalEnvServiceModelStatus.java
index 2278c8cd9d..a7444a49d1 100644
--- a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/OperationalEnvServiceModelStatus.java
+++ b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/OperationalEnvServiceModelStatus.java
@@ -22,6 +22,7 @@ package org.onap.so.db.request.beans;
 
 import java.io.Serializable;
 import java.util.Date;
+import java.util.Objects;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.Id;
@@ -31,7 +32,6 @@ import javax.persistence.PreUpdate;
 import javax.persistence.Table;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
-import java.util.Objects;
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
 /**
diff --git a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/RequestProcessingData.java b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/RequestProcessingData.java
index e386789c7f..c52d311146 100644
--- a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/RequestProcessingData.java
+++ b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/beans/RequestProcessingData.java
@@ -48,7 +48,6 @@ import com.openpojo.business.annotation.BusinessKey;
  */
 
 @Entity
-
 @JsonInclude(Include.NON_NULL)
 @Table(name = "request_processing_data")
 public class RequestProcessingData implements Serializable {
diff --git a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/client/RequestsDbClient.java b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/client/RequestsDbClient.java
index 6aa00caeed..17b22ec216 100644
--- a/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/client/RequestsDbClient.java
+++ b/mso-api-handlers/mso-requests-db/src/main/java/org/onap/so/db/request/client/RequestsDbClient.java
@@ -22,32 +22,26 @@ package org.onap.so.db.request.client;
 
 import java.net.URI;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
 import javax.annotation.PostConstruct;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.UriBuilder;
 import org.apache.http.HttpStatus;
-import org.onap.logging.filter.spring.SpringClientPayloadFilter;
 import org.onap.so.db.request.beans.ArchivedInfraRequests;
 import org.onap.so.db.request.beans.InfraActiveRequests;
 import org.onap.so.db.request.beans.OperationStatus;
 import org.onap.so.db.request.beans.OperationalEnvDistributionStatus;
 import org.onap.so.db.request.beans.OperationalEnvServiceModelStatus;
+import org.onap.so.db.request.beans.OrchestrationTask;
 import org.onap.so.db.request.beans.RequestProcessingData;
 import org.onap.so.db.request.beans.ResourceOperationStatus;
 import org.onap.so.db.request.beans.SiteStatus;
 import org.onap.so.db.request.beans.WatchdogComponentDistributionStatus;
 import org.onap.so.db.request.beans.WatchdogDistributionStatus;
 import org.onap.so.db.request.beans.WatchdogServiceModVerIdLookup;
-import org.onap.so.db.request.beans.OrchestrationTask;
 import org.onap.so.db.request.data.controller.InstanceNameDuplicateCheckRequest;
-import org.onap.so.logging.jaxrs.filter.SOSpringClientFilter;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Primary;
@@ -56,14 +50,9 @@ import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.ResponseEntity;
-import org.springframework.http.client.BufferingClientHttpRequestFactory;
-import org.springframework.http.client.ClientHttpRequestFactory;
-import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
 import org.springframework.stereotype.Component;
 import org.springframework.web.client.HttpClientErrorException;
 import org.springframework.web.client.RestTemplate;
-import uk.co.blackpepper.bowman.ClientFactory;
-import uk.co.blackpepper.bowman.Configuration;
 
 @Component("RequestsDbClient")
 @Primary
@@ -166,25 +155,6 @@ public class RequestsDbClient {
         return endpoint;
     }
 
-    protected ClientFactory getClientFactory() {
-        URI baseUri = UriBuilder.fromUri(getEndpoint()).build();
-        ClientHttpRequestFactory factory =
-                new BufferingClientHttpRequestFactory(new HttpComponentsClientHttpRequestFactory());
-
-        return Configuration.builder().setBaseUri(baseUri).setClientHttpRequestFactory(factory)
-                .setRestTemplateConfigurer(restTemplate -> {
-                    restTemplate.getInterceptors().add((new SOSpringClientFilter()));
-                    restTemplate.getInterceptors().add((new SpringClientPayloadFilter()));
-
-                    restTemplate.getInterceptors().add((request, body, execution) -> {
-
-                        request.getHeaders().add(HttpHeaders.AUTHORIZATION, msoAdaptersAuth);
-                        return execution.execute(request, body);
-                    });
-                }).build().buildClientFactory();
-    }
-
-
     public List<InfraActiveRequests> getCloudOrchestrationFiltersFromInfraActive(Map<String, String> orchestrationMap) {
         URI uri = getUri(cloudOrchestrationFiltersFromInfraActive);
         HttpHeaders headers = getHttpHeaders();
@@ -201,30 +171,21 @@ public class RequestsDbClient {
     }
 
     public List<InfraActiveRequests> getInProgressVolumeGroupsAndVfModules() {
-        HttpHeaders headers = getHttpHeaders();
         URI uri = getUri(endpoint + getInProgressVolumeGroupsAndVfModules);
-        HttpEntity<Map<String, List<String>>> entity = new HttpEntity<>(headers);
-        return restTemplate
-                .exchange(uri, HttpMethod.GET, entity, new ParameterizedTypeReference<List<InfraActiveRequests>>() {})
-                .getBody();
+
+        return getMultipleResponse(uri, new ParameterizedTypeReference<List<InfraActiveRequests>>() {});
+
     }
 
     public InfraActiveRequests getInfraActiveRequestbyRequestId(String requestId) {
-        try {
-            HttpEntity<?> entity = getHttpEntity();
-            InfraActiveRequests infraActiveRequests =
-                    restTemplate.exchange(getUri(endpoint + "/infraActiveRequests/" + requestId), HttpMethod.GET,
-                            entity, InfraActiveRequests.class).getBody();
-            if (infraActiveRequests != null) {
-                infraActiveRequests.setRequestId(requestId);
-            }
-            return infraActiveRequests;
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
+
+
+        InfraActiveRequests infraActiveRequests =
+                getSingleResponse(getUri(endpoint + "/infraActiveRequests/" + requestId), InfraActiveRequests.class);
+        if (infraActiveRequests != null) {
+            infraActiveRequests.setRequestId(requestId);
         }
+        return infraActiveRequests;
     }
 
     public List<InfraActiveRequests> getOrchestrationFiltersFromInfraActive(
@@ -238,9 +199,8 @@ public class RequestsDbClient {
     }
 
     public InfraActiveRequests checkVnfIdStatus(String operationalEnvironmentId) {
-        HttpEntity<?> entity = getHttpEntity();
         URI uri = getUri(checkVnfIdStatus + operationalEnvironmentId);
-        return restTemplate.exchange(uri, HttpMethod.GET, entity, InfraActiveRequests.class).getBody();
+        return getSingleResponse(uri, InfraActiveRequests.class);
     }
 
     public InfraActiveRequests checkInstanceNameDuplicate(Map<String, String> instanceIdMap, String instanceName,
@@ -249,66 +209,40 @@ public class RequestsDbClient {
         URI uri = getUri(checkInstanceNameDuplicate);
         HttpEntity<InstanceNameDuplicateCheckRequest> entity = new HttpEntity<>(
                 new InstanceNameDuplicateCheckRequest(instanceIdMap, instanceName, requestScope), headers);
-        try {
-            ResponseEntity<InfraActiveRequests> response =
-                    restTemplate.exchange(uri, HttpMethod.POST, entity, InfraActiveRequests.class);
-            if (response != null && response.hasBody()) {
-                return restTemplate.exchange(uri, HttpMethod.POST, entity, InfraActiveRequests.class).getBody();
-            } else {
-                return null;
-            }
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
-        }
+
+        return postSingleResponse(uri, entity, InfraActiveRequests.class);
 
     }
 
     public OperationStatus getOneByServiceIdAndOperationId(String serviceId, String operationId) {
-        try {
-            HttpEntity<?> entity = getHttpEntity();
-            OperationStatus operationStatus = restTemplate.exchange(getUri(
-                    UriBuilder.fromUri(getUri(findOneByServiceIdAndOperationIdURI)).queryParam(SERVICE_ID, serviceId)
-                            .queryParam(OPERATION_ID, operationId).build().toString()),
-                    HttpMethod.GET, entity, OperationStatus.class).getBody();
-            if (operationStatus != null) {
-                operationStatus.setServiceId(serviceId);
-                operationStatus.setOperationId(operationId);
-            }
-
-            return operationStatus;
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
+        OperationStatus operationStatus = getSingleResponse(
+                getUri(UriBuilder.fromUri(getUri(findOneByServiceIdAndOperationIdURI)).queryParam(SERVICE_ID, serviceId)
+                        .queryParam(OPERATION_ID, operationId).build().toString()),
+                OperationStatus.class);
+        if (operationStatus != null) {
+            operationStatus.setServiceId(serviceId);
+            operationStatus.setOperationId(operationId);
         }
+        return operationStatus;
     }
 
     public OperationalEnvServiceModelStatus findOneByOperationalEnvIdAndServiceModelVersionIdAndRequestId(
             String operationalEnvironmentId, String serviceModelVersionId, String requestId) {
-        try {
-            HttpEntity<?> entity = getHttpEntity();
-            OperationalEnvServiceModelStatus modelStatus = restTemplate.exchange(
-                    getUri(UriBuilder.fromUri(findOneByOperationalEnvIdAndServiceModelVersionIdAndRequestIdURI)
-                            .queryParam(OPERATIONAL_ENVIRONMENT_ID, operationalEnvironmentId)
-                            .queryParam(SERVICE_MODEL_VERSION_ID, serviceModelVersionId)
-                            .queryParam(REQUEST_ID, requestId).build().toString()),
-                    HttpMethod.GET, entity, OperationalEnvServiceModelStatus.class).getBody();
-            if (null != modelStatus) {
-                modelStatus.setOperationalEnvId(operationalEnvironmentId);
-                modelStatus.setServiceModelVersionId(serviceModelVersionId);
-                modelStatus.setRequestId(requestId);
-            }
-            return modelStatus;
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
+
+        OperationalEnvServiceModelStatus modelStatus =
+                getSingleResponse(
+                        getUri(UriBuilder.fromUri(findOneByOperationalEnvIdAndServiceModelVersionIdAndRequestIdURI)
+                                .queryParam(OPERATIONAL_ENVIRONMENT_ID, operationalEnvironmentId)
+                                .queryParam(SERVICE_MODEL_VERSION_ID, serviceModelVersionId)
+                                .queryParam(REQUEST_ID, requestId).build().toString()),
+                        OperationalEnvServiceModelStatus.class);
+        if (null != modelStatus) {
+            modelStatus.setOperationalEnvId(operationalEnvironmentId);
+            modelStatus.setServiceModelVersionId(serviceModelVersionId);
+            modelStatus.setRequestId(requestId);
         }
+        return modelStatus;
+
     }
 
     public List<OperationalEnvServiceModelStatus> getAllByOperationalEnvIdAndRequestId(String operationalEnvironmentId,
@@ -320,30 +254,18 @@ public class RequestsDbClient {
     }
 
     public OperationalEnvDistributionStatus getDistributionStatusById(String distributionId) {
-        try {
-            HttpEntity<?> entity = getHttpEntity();
-            OperationalEnvDistributionStatus distributionStatus =
-                    restTemplate.exchange(getUri(operationalEnvDistributionStatusURI + distributionId), HttpMethod.GET,
-                            entity, OperationalEnvDistributionStatus.class).getBody();
-            if (null != distributionStatus) {
-                distributionStatus.setDistributionId(distributionId);
-            }
-            return distributionStatus;
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
+
+        OperationalEnvDistributionStatus distributionStatus = getSingleResponse(
+                getUri(operationalEnvDistributionStatusURI + distributionId), OperationalEnvDistributionStatus.class);
+        if (null != distributionStatus) {
+            distributionStatus.setDistributionId(distributionId);
         }
+        return distributionStatus;
+
     }
 
     private List<OperationalEnvServiceModelStatus> getMultipleOperationalEnvServiceModelStatus(URI uri) {
-        Iterable<OperationalEnvServiceModelStatus> iterable =
-                getClientFactory().create(OperationalEnvServiceModelStatus.class).getAll(uri);
-        List<OperationalEnvServiceModelStatus> serviceModelStatuses = new ArrayList<>();
-        Iterator<OperationalEnvServiceModelStatus> statusIterator = iterable.iterator();
-        statusIterator.forEachRemaining(serviceModelStatuses::add);
-        return serviceModelStatuses;
+        return getMultipleResponse(uri, new ParameterizedTypeReference<List<OperationalEnvServiceModelStatus>>() {});
     }
 
     public void save(InfraActiveRequests infraActiveRequests) {
@@ -376,38 +298,16 @@ public class RequestsDbClient {
     }
 
     public InfraActiveRequests getInfraActiveRequests(String requestId, String basicAuth, String host) {
-        RestTemplate template = new RestTemplate();
-        HttpHeaders headers = new HttpHeaders();
-        headers.set(HttpHeaders.AUTHORIZATION, basicAuth);
-        headers.set(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON);
-        headers.set(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON);
+
         URI uri = getUri(host + "/infraActiveRequests/" + requestId);
-        try {
-            InfraActiveRequests infraActiveRequests = template
-                    .exchange(uri, HttpMethod.GET, new HttpEntity<>(headers), InfraActiveRequests.class).getBody();
-            if (infraActiveRequests != null) {
-                infraActiveRequests.setRequestId(requestId);
-            }
-            return infraActiveRequests;
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
-        }
+
+        return getSingleResponse(uri, InfraActiveRequests.class);
     }
 
     public void updateInfraActiveRequests(InfraActiveRequests request, String basicAuth, String host) {
-        RestTemplate template = new RestTemplate();
-        template.getInterceptors().add(new SOSpringClientFilter());
-        template.getInterceptors().add(new SpringClientPayloadFilter());
-        HttpHeaders headers = new HttpHeaders();
-        headers.set(HttpHeaders.AUTHORIZATION, basicAuth);
-        headers.set(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON);
-        headers.set(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON);
         URI uri = getUri(host + "/infraActiveRequests/" + request.getRequestId());
-        HttpEntity<InfraActiveRequests> entity = new HttpEntity<>(request, headers);
-        template.put(uri, entity);
+        HttpEntity<InfraActiveRequests> entity = new HttpEntity<>(request, getHttpHeaders());
+        restTemplate.put(uri, entity);
     }
 
     protected URI getUri(String uri) {
@@ -437,41 +337,30 @@ public class RequestsDbClient {
     public List<RequestProcessingData> getExternalRequestProcessingDataBySoRequestId(String soRequestId) {
         URI uri = getUri(UriBuilder.fromUri(getEndpoint() + findBySoRequestIdAndIsDataInternalOrderByGroupingIdDesc)
                 .queryParam(SO_REQUEST_ID, soRequestId).queryParam(IS_INTERNAL_DATA, false).build().toString());
-        ResponseEntity<RequestProcessingData[]> array =
-                restTemplate.exchange(uri, HttpMethod.GET, getHttpEntity(), RequestProcessingData[].class);
-        if (array != null) {
-            return Arrays.asList(array.getBody());
-        } else {
-            return null;
-        }
+        return getMultipleResponse(uri, new ParameterizedTypeReference<List<RequestProcessingData>>() {});
     }
 
     public RequestProcessingData getRequestProcessingDataBySoRequestIdAndNameAndGrouping(String soRequestId,
             String name, String groupingId) {
-        return getClientFactory().create(RequestProcessingData.class)
-                .get(getUri(UriBuilder.fromUri(endpoint + findBySoRequestIdAndGroupIdAndName)
-                        .queryParam(SO_REQUEST_ID, soRequestId).queryParam(NAME, name)
-                        .queryParam(GROUPING_ID, groupingId).build().toString()));
+        return getSingleResponse(getUri(
+                UriBuilder.fromUri(endpoint + findBySoRequestIdAndGroupIdAndName).queryParam(SO_REQUEST_ID, soRequestId)
+                        .queryParam(NAME, name).queryParam(GROUPING_ID, groupingId).build().toString()),
+                RequestProcessingData.class);
     }
 
     public List<RequestProcessingData> getRequestProcessingDataByGroupingIdAndNameAndTag(String groupingId, String name,
             String tag) {
-        Iterable<RequestProcessingData> requestProcessingDataListIt =
-                getClientFactory().create(RequestProcessingData.class)
-                        .getAll(getUri(UriBuilder.fromUri(endpoint + findByGroupingIdAndNameAndTag)
-                                .queryParam(GROUPING_ID, groupingId).queryParam(NAME, name).queryParam(TAG, tag).build()
-                                .toString()));
-
-        List<RequestProcessingData> requestProcessingDataList =
-                StreamSupport.stream(requestProcessingDataListIt.spliterator(), false).collect(Collectors.toList());
 
-        return requestProcessingDataList;
+        return getMultipleResponse(
+                getUri(UriBuilder.fromUri(endpoint + findByGroupingIdAndNameAndTag).queryParam(GROUPING_ID, groupingId)
+                        .queryParam(NAME, name).queryParam(TAG, tag).build().toString()),
+                new ParameterizedTypeReference<List<RequestProcessingData>>() {});
     }
 
     public RequestProcessingData getRequestProcessingDataBySoRequestIdAndName(String soRequestId, String name) {
-        return getClientFactory().create(RequestProcessingData.class)
-                .get(getUri(UriBuilder.fromUri(endpoint + findBySoRequestIdAndName)
-                        .queryParam(SO_REQUEST_ID, soRequestId).queryParam(NAME, name).build().toString()));
+        return getSingleResponse(getUri(UriBuilder.fromUri(endpoint + findBySoRequestIdAndName)
+                .queryParam(SO_REQUEST_ID, soRequestId).queryParam(NAME, name).build().toString()),
+                RequestProcessingData.class);
     }
 
 
@@ -491,26 +380,14 @@ public class RequestsDbClient {
     }
 
     private List<RequestProcessingData> getRequestProcessingData(URI uri) {
-        Iterable<RequestProcessingData> requestProcessingDataIterator =
-                getClientFactory().create(RequestProcessingData.class).getAll(uri);
-        List<RequestProcessingData> requestProcessingDataList = new ArrayList<>();
-        Iterator<RequestProcessingData> it = requestProcessingDataIterator.iterator();
-        it.forEachRemaining(requestProcessingDataList::add);
-        return requestProcessingDataList;
+        return getMultipleResponse(uri, new ParameterizedTypeReference<List<RequestProcessingData>>() {});
     }
 
     public InfraActiveRequests findOneByRequestId(String requestId) {
-        try {
-            HttpEntity<?> entity = getHttpEntity();
-            return restTemplate.exchange(
-                    getUri(UriBuilder.fromUri(findOneByRequestId).queryParam(REQUEST_ID, requestId).build().toString()),
-                    HttpMethod.GET, entity, InfraActiveRequests.class).getBody();
-        } catch (HttpClientErrorException e) {
-            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
-                return null;
-            }
-            throw e;
-        }
+        return getSingleResponse(
+                getUri(UriBuilder.fromUri(findOneByRequestId).queryParam(REQUEST_ID, requestId).build().toString()),
+                InfraActiveRequests.class);
+
     }
 
     // From and To are defaulted to ignore start/endtime on query to database
@@ -525,11 +402,8 @@ public class RequestsDbClient {
     }
 
     public List<OrchestrationTask> getAllOrchestrationTasks() {
-        String url = UriBuilder.fromUri(getUri(orchestrationTasksURI)).build().toString();
-        HttpEntity<?> entity = getHttpEntity();
-        return restTemplate
-                .exchange(url, HttpMethod.GET, entity, new ParameterizedTypeReference<List<OrchestrationTask>>() {})
-                .getBody();
+        return getMultipleResponse(getUri(orchestrationTasksURI),
+                new ParameterizedTypeReference<List<OrchestrationTask>>() {});
     }
 
     public OrchestrationTask getOrchestrationTask(String taskId) {
@@ -605,4 +479,54 @@ public class RequestsDbClient {
         return new HttpEntity<>(headers);
     }
 
+    private <T> T getSingleResponse(URI uri, Class<T> clazz) {
+        try {
+            HttpEntity<?> entity = getHttpEntity();
+            return restTemplate.exchange(uri, HttpMethod.GET, entity, clazz).getBody();
+        } catch (HttpClientErrorException e) {
+            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
+                return null;
+            }
+            throw e;
+        }
+    }
+
+    private <T> List<T> getMultipleResponse(URI uri, ParameterizedTypeReference<List<T>> type) {
+        try {
+            HttpEntity<?> entity = getHttpEntity();
+            return restTemplate.exchange(uri, HttpMethod.GET, entity, type).getBody();
+        } catch (HttpClientErrorException e) {
+            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
+                return new ArrayList<T>();
+            }
+            throw e;
+        }
+    }
+
+    private <T> T postSingleResponse(URI uri, HttpEntity<?> payload, Class<T> clazz) {
+        try {
+            HttpEntity<?> entity = new HttpEntity<>(payload.getBody(), getHttpHeaders());
+            return restTemplate.exchange(uri, HttpMethod.POST, entity, clazz).getBody();
+        } catch (HttpClientErrorException e) {
+            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
+                return null;
+            }
+            throw e;
+        }
+    }
+
+    private <T> List<T> postMultipleResponse(URI uri, HttpEntity<?> payload, ParameterizedTypeReference<List<T>> type) {
+        try {
+            HttpEntity<?> entity = new HttpEntity<>(payload.getBody(), getHttpHeaders());
+            ResponseEntity<List<T>> result = restTemplate.exchange(uri, HttpMethod.POST, entity, type);
+
+            return result.getBody();
+        } catch (HttpClientErrorException e) {
+            if (HttpStatus.SC_NOT_FOUND == e.getStatusCode().value()) {
+                return new ArrayList<T>();
+            }
+            throw e;
+        }
+    }
+
 }