6c9012bc68553b9ea1d13857d00853e475f9cc27
[ccsdk/oran.git] /
1 /*-
2  * ========================LICENSE_START=================================
3  * ONAP : ccsdk oran
4  * ======================================================================
5  * Copyright (C) 2019-2020 Nordix Foundation. All rights reserved.
6  * ======================================================================
7  * Licensed under the Apache License, Version 2.0 (the "License");
8  * you may not use this file except in compliance with the License.
9  * You may obtain a copy of the License at
10  *
11  *      http://www.apache.org/licenses/LICENSE-2.0
12  *
13  * Unless required by applicable law or agreed to in writing, software
14  * distributed under the License is distributed on an "AS IS" BASIS,
15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  * See the License for the specific language governing permissions and
17  * limitations under the License.
18  * ========================LICENSE_END===================================
19  */
20
21 package org.onap.ccsdk.oran.a1policymanagementservice.controllers.v2;
22
23 import com.google.gson.Gson;
24 import com.google.gson.GsonBuilder;
25
26 import io.swagger.annotations.Api;
27 import io.swagger.annotations.ApiOperation;
28 import io.swagger.annotations.ApiParam;
29 import io.swagger.annotations.ApiResponse;
30 import io.swagger.annotations.ApiResponses;
31
32 import java.lang.invoke.MethodHandles;
33 import java.time.Instant;
34 import java.util.ArrayList;
35 import java.util.Collection;
36 import java.util.List;
37
38 import lombok.Getter;
39
40 import org.onap.ccsdk.oran.a1policymanagementservice.clients.A1ClientFactory;
41 import org.onap.ccsdk.oran.a1policymanagementservice.controllers.VoidResponse;
42 import org.onap.ccsdk.oran.a1policymanagementservice.exceptions.ServiceException;
43 import org.onap.ccsdk.oran.a1policymanagementservice.repository.ImmutablePolicy;
44 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Lock.LockType;
45 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Policies;
46 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Policy;
47 import org.onap.ccsdk.oran.a1policymanagementservice.repository.PolicyType;
48 import org.onap.ccsdk.oran.a1policymanagementservice.repository.PolicyTypes;
49 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Ric;
50 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Rics;
51 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Service;
52 import org.onap.ccsdk.oran.a1policymanagementservice.repository.Services;
53 import org.slf4j.Logger;
54 import org.slf4j.LoggerFactory;
55 import org.springframework.beans.factory.annotation.Autowired;
56 import org.springframework.http.HttpStatus;
57 import org.springframework.http.MediaType;
58 import org.springframework.http.ResponseEntity;
59 import org.springframework.web.bind.annotation.DeleteMapping;
60 import org.springframework.web.bind.annotation.GetMapping;
61 import org.springframework.web.bind.annotation.PutMapping;
62 import org.springframework.web.bind.annotation.RequestBody;
63 import org.springframework.web.bind.annotation.RequestParam;
64 import org.springframework.web.bind.annotation.RestController;
65 import org.springframework.web.reactive.function.client.WebClientResponseException;
66 import reactor.core.publisher.Mono;
67
68 @RestController("PolicyControllerV2")
69 @Api(tags = {Consts.V2_API_NAME})
70 public class PolicyController {
71
72     public static class RejectionException extends Exception {
73         private static final long serialVersionUID = 1L;
74
75         @Getter
76         private final HttpStatus status;
77
78         public RejectionException(String message, HttpStatus status) {
79             super(message);
80             this.status = status;
81         }
82     }
83
84     @Autowired
85     private Rics rics;
86     @Autowired
87     private PolicyTypes policyTypes;
88     @Autowired
89     private Policies policies;
90     @Autowired
91     private A1ClientFactory a1ClientFactory;
92     @Autowired
93     private Services services;
94
95     private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
96     private static Gson gson = new GsonBuilder() //
97             .serializeNulls() //
98             .create(); //
99
100     @GetMapping(path = Consts.V2_API_ROOT + "/policy-schemas", produces = MediaType.APPLICATION_JSON_VALUE)
101     @ApiOperation(value = "Returns policy type schema definitions")
102     @ApiResponses(value = { //
103             @ApiResponse(code = 200, message = "Policy schemas", response = PolicySchemaList.class), //
104             @ApiResponse(code = 404, message = "Near-RT RIC is not found", response = ErrorResponse.ErrorInfo.class)})
105     public ResponseEntity<Object> getPolicySchemas( //
106             @ApiParam(name = Consts.RIC_ID_PARAM, required = false,
107                     value = "The identity of the Near-RT RIC to get the definitions for.") //
108             @RequestParam(name = Consts.RIC_ID_PARAM, required = false) String ricId,
109             @ApiParam(name = Consts.POLICY_TYPE_ID_PARAM, required = true,
110                     value = "The identity of the policy type to get the definition for. When this parameter is given, max one schema will be returned") //
111             @RequestParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false) String policyTypeId) {
112         try {
113             Ric ric = ricId == null ? null : rics.getRic(ricId);
114             if (ric == null && policyTypeId == null) {
115                 Collection<PolicyType> types = this.policyTypes.getAll();
116                 return new ResponseEntity<>(toPolicyTypeSchemasJson(types), HttpStatus.OK);
117             } else if (ric != null && policyTypeId != null) {
118                 synchronized (ric) {
119                     assertRicStateIdleSync(ric);
120                     Collection<PolicyType> types = new ArrayList<>();
121                     if (rics.getRic(ricId).isSupportingType(policyTypeId)) {
122                         types.add(policyTypes.getType(policyTypeId));
123                     }
124                     return new ResponseEntity<>(toPolicyTypeSchemasJson(types), HttpStatus.OK);
125                 }
126             } else if (ric != null) {
127                 synchronized (ric) {
128                     assertRicStateIdleSync(ric);
129                     Collection<PolicyType> types = rics.getRic(ricId).getSupportedPolicyTypes();
130                     return new ResponseEntity<>(toPolicyTypeSchemasJson(types), HttpStatus.OK);
131                 }
132             } else {
133                 Collection<PolicyType> types = new ArrayList<>();
134                 types.add(policyTypes.getType(policyTypeId));
135                 return new ResponseEntity<>(toPolicyTypeSchemasJson(types), HttpStatus.OK);
136             }
137         } catch (ServiceException e) {
138             return ErrorResponse.create(e, HttpStatus.NOT_FOUND);
139         }
140     }
141
142     @GetMapping(path = Consts.V2_API_ROOT + "/policy-types", produces = MediaType.APPLICATION_JSON_VALUE)
143     @ApiOperation(value = "Query policy type identities", produces = MediaType.APPLICATION_JSON_VALUE)
144     @ApiResponses(value = {@ApiResponse(code = 200, message = "Policy type IDs", response = PolicyTypeIdList.class),
145             @ApiResponse(code = 404, message = "Near-RT RIC is not found", response = ErrorResponse.ErrorInfo.class)})
146     public ResponseEntity<Object> getPolicyTypes( //
147             @ApiParam(name = Consts.RIC_ID_PARAM, required = false,
148                     value = "The identity of the Near-RT RIC to get types for.") //
149             @RequestParam(name = Consts.RIC_ID_PARAM, required = false) String ricId) {
150         if (ricId == null) {
151             Collection<PolicyType> types = this.policyTypes.getAll();
152             return new ResponseEntity<>(toPolicyTypeIdsJson(types), HttpStatus.OK);
153         } else {
154             try {
155                 Collection<PolicyType> types = rics.getRic(ricId).getSupportedPolicyTypes();
156                 return new ResponseEntity<>(toPolicyTypeIdsJson(types), HttpStatus.OK);
157             } catch (ServiceException e) {
158                 return ErrorResponse.create(e, HttpStatus.NOT_FOUND);
159             }
160         }
161     }
162
163     @GetMapping(path = Consts.V2_API_ROOT + "/policy", produces = MediaType.APPLICATION_JSON_VALUE)
164     @ApiOperation(value = "Returns a policy configuration") //
165     @ApiResponses(value = { //
166             @ApiResponse(code = 200, message = "Policy found", response = JsonObject.class), //
167             @ApiResponse(code = 404, message = "Policy is not found", response = ErrorResponse.ErrorInfo.class)} //
168     )
169     public ResponseEntity<Object> getPolicy( //
170             @ApiParam(name = Consts.POLICY_ID_PARAM, required = true, value = "The identity of the policy instance.") //
171             @RequestParam(name = Consts.POLICY_ID_PARAM, required = true) String id) {
172         try {
173             Policy p = policies.getPolicy(id);
174             return new ResponseEntity<>(p.json(), HttpStatus.OK);
175         } catch (ServiceException e) {
176             return ErrorResponse.create(e, HttpStatus.NOT_FOUND);
177         }
178     }
179
180     @DeleteMapping(Consts.V2_API_ROOT + "/policy")
181     @ApiOperation(value = "Delete a policy")
182     @ApiResponses(value = { //
183             @ApiResponse(code = 200, message = "Not used", response = VoidResponse.class),
184             @ApiResponse(code = 204, message = "Policy deleted", response = VoidResponse.class),
185             @ApiResponse(code = 404, message = "Policy is not found", response = ErrorResponse.ErrorInfo.class),
186             @ApiResponse(code = 423, message = "Near-RT RIC is not operational",
187                     response = ErrorResponse.ErrorInfo.class)})
188     public Mono<ResponseEntity<Object>> deletePolicy( //
189             @ApiParam(name = Consts.POLICY_ID_PARAM, required = true, value = "The identity of the policy instance.") //
190             @RequestParam(name = Consts.POLICY_ID_PARAM, required = true) String id) {
191         try {
192             Policy policy = policies.getPolicy(id);
193             keepServiceAlive(policy.ownerServiceId());
194             Ric ric = policy.ric();
195             return ric.getLock().lock(LockType.SHARED) //
196                     .flatMap(notUsed -> assertRicStateIdle(ric)) //
197                     .flatMap(notUsed -> a1ClientFactory.createA1Client(policy.ric())) //
198                     .doOnNext(notUsed -> policies.remove(policy)) //
199                     .flatMap(client -> client.deletePolicy(policy)) //
200                     .doOnNext(notUsed -> ric.getLock().unlockBlocking()) //
201                     .doOnError(notUsed -> ric.getLock().unlockBlocking()) //
202                     .flatMap(notUsed -> Mono.just(new ResponseEntity<>(HttpStatus.NO_CONTENT)))
203                     .onErrorResume(this::handleException);
204         } catch (ServiceException e) {
205             return ErrorResponse.createMono(e, HttpStatus.NOT_FOUND);
206         }
207     }
208
209     @PutMapping(path = Consts.V2_API_ROOT + "/policy", produces = MediaType.APPLICATION_JSON_VALUE)
210     @ApiOperation(value = "Create or update a policy")
211     @ApiResponses(value = { //
212             @ApiResponse(code = 201, message = "Policy created", response = VoidResponse.class), //
213             @ApiResponse(code = 200, message = "Policy updated", response = VoidResponse.class), //
214             @ApiResponse(code = 423, message = "Near-RT RIC is not operational",
215                     response = ErrorResponse.ErrorInfo.class), //
216             @ApiResponse(code = 404, message = "Near-RT RIC or policy type is not found",
217                     response = ErrorResponse.ErrorInfo.class) //
218     })
219     public Mono<ResponseEntity<Object>> putPolicy( //
220             @ApiParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false, value = "The identity of the policy type.") //
221             @RequestParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false, defaultValue = "") String policyTypeId, //
222             @ApiParam(name = Consts.POLICY_ID_PARAM, required = true, value = "The identity of the policy instance.") //
223             @RequestParam(name = Consts.POLICY_ID_PARAM, required = true) String instanceId, //
224             @ApiParam(name = Consts.RIC_ID_PARAM, required = true,
225                     value = "The identity of the Near-RT RIC where the policy will be " + //
226                             "created.") //
227             @RequestParam(name = Consts.RIC_ID_PARAM, required = true) String ricId, //
228             @ApiParam(name = Consts.SERVICE_ID_PARAM, required = true,
229                     value = "The identity of the service creating the policy.") //
230             @RequestParam(name = Consts.SERVICE_ID_PARAM, required = true) String serviceId, //
231             @ApiParam(name = Consts.TRANSIENT_PARAM, required = false,
232                     value = "If the policy is transient or not (boolean " + //
233                             "defaulted to false). A policy is transient if it will not be recreated in the Near-RT RIC "
234                             + //
235                             "when it has been lost (for instance due to a restart)") //
236             @RequestParam(name = Consts.TRANSIENT_PARAM, required = false, defaultValue = "false") boolean isTransient, //
237             @RequestBody Object jsonBody) {
238
239         String jsonString = gson.toJson(jsonBody);
240         Ric ric = rics.get(ricId);
241         PolicyType type = policyTypes.get(policyTypeId);
242         keepServiceAlive(serviceId);
243         if (ric == null || type == null) {
244             return ErrorResponse.createMono("Near-RT RIC or policy type not found", HttpStatus.NOT_FOUND);
245         }
246         Policy policy = ImmutablePolicy.builder() //
247                 .id(instanceId) //
248                 .json(jsonString) //
249                 .type(type) //
250                 .ric(ric) //
251                 .ownerServiceId(serviceId) //
252                 .lastModified(Instant.now()) //
253                 .isTransient(isTransient) //
254                 .build();
255
256         final boolean isCreate = this.policies.get(policy.id()) == null;
257
258         return ric.getLock().lock(LockType.SHARED) //
259                 .flatMap(notUsed -> assertRicStateIdle(ric)) //
260                 .flatMap(notUsed -> checkSupportedType(ric, type)) //
261                 .flatMap(notUsed -> validateModifiedPolicy(policy)) //
262                 .flatMap(notUsed -> a1ClientFactory.createA1Client(ric)) //
263                 .flatMap(client -> client.putPolicy(policy)) //
264                 .doOnNext(notUsed -> policies.put(policy)) //
265                 .doOnNext(notUsed -> ric.getLock().unlockBlocking()) //
266                 .doOnError(trowable -> ric.getLock().unlockBlocking()) //
267                 .flatMap(notUsed -> Mono.just(new ResponseEntity<>(isCreate ? HttpStatus.CREATED : HttpStatus.OK))) //
268                 .onErrorResume(this::handleException);
269     }
270
271     private Mono<ResponseEntity<Object>> handleException(Throwable throwable) {
272         if (throwable instanceof WebClientResponseException) {
273             WebClientResponseException e = (WebClientResponseException) throwable;
274             return ErrorResponse.createMono(e.getResponseBodyAsString(), e.getStatusCode());
275         } else if (throwable instanceof RejectionException) {
276             RejectionException e = (RejectionException) throwable;
277             return ErrorResponse.createMono(e.getMessage(), e.getStatus());
278         } else {
279             return ErrorResponse.createMono(throwable.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
280         }
281     }
282
283     private Mono<Object> validateModifiedPolicy(Policy policy) {
284         // Check that ric is not updated
285         Policy current = this.policies.get(policy.id());
286         if (current != null && !current.ric().id().equals(policy.ric().id())) {
287             RejectionException e = new RejectionException("Policy cannot change RIC, policyId: " + current.id() + //
288                     ", RIC ID: " + current.ric().id() + //
289                     ", new ID: " + policy.ric().id(), HttpStatus.CONFLICT);
290             logger.debug("Request rejected, {}", e.getMessage());
291             return Mono.error(e);
292         }
293         return Mono.just("{}");
294     }
295
296     private Mono<Object> checkSupportedType(Ric ric, PolicyType type) {
297         if (!ric.isSupportingType(type.id())) {
298             logger.debug("Request rejected, type not supported, RIC: {}", ric);
299             RejectionException e = new RejectionException("Type: " + type.id() + " not supported by RIC: " + ric.id(),
300                     HttpStatus.NOT_FOUND);
301             return Mono.error(e);
302         }
303         return Mono.just("{}");
304     }
305
306     private void assertRicStateIdleSync(Ric ric) throws ServiceException {
307         if (ric.getState() != Ric.RicState.AVAILABLE) {
308             throw new ServiceException("Near-RT RIC: " + ric.id() + " is " + ric.getState());
309         }
310     }
311
312     private Mono<Object> assertRicStateIdle(Ric ric) {
313         if (ric.getState() == Ric.RicState.AVAILABLE) {
314             return Mono.just("{}");
315         } else {
316             logger.debug("Request rejected Near-RT RIC not IDLE, ric: {}", ric);
317             RejectionException e = new RejectionException(
318                     "Near-RT RIC: is not operational, id: " + ric.id() + ", state: " + ric.getState(),
319                     HttpStatus.LOCKED);
320             return Mono.error(e);
321         }
322     }
323
324     static final String GET_POLICIES_QUERY_DETAILS =
325             "Returns a list of A1 policies matching given search criteria. <br>" //
326                     + "If several query parameters are defined, the policies matching all conditions are returned.";
327
328     @GetMapping(path = Consts.V2_API_ROOT + "/policies", produces = MediaType.APPLICATION_JSON_VALUE)
329     @ApiOperation(value = "Query for existing A1 policies", notes = GET_POLICIES_QUERY_DETAILS)
330     @ApiResponses(value = { //
331             @ApiResponse(code = 200, message = "Policies", response = PolicyInfoList.class),
332             @ApiResponse(code = 404, message = "Near-RT RIC, policy type or service not found",
333                     response = ErrorResponse.ErrorInfo.class)})
334     public ResponseEntity<Object> getPolicies( //
335             @ApiParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false,
336                     value = "The identity of the policy type to get policies for.") //
337             @RequestParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false) String type, //
338             @ApiParam(name = Consts.RIC_ID_PARAM, required = false,
339                     value = "The identity of the Near-RT RIC to get policies for.") //
340             @RequestParam(name = Consts.RIC_ID_PARAM, required = false) String ric, //
341             @ApiParam(name = Consts.SERVICE_ID_PARAM, required = false,
342                     value = "The identity of the service to get policies for.") //
343             @RequestParam(name = Consts.SERVICE_ID_PARAM, required = false) String service) //
344     {
345         if ((type != null && this.policyTypes.get(type) == null)) {
346             return ErrorResponse.create("Policy type not found", HttpStatus.NOT_FOUND);
347         }
348         if ((ric != null && this.rics.get(ric) == null)) {
349             return ErrorResponse.create("Near-RT RIC not found", HttpStatus.NOT_FOUND);
350         }
351
352         String filteredPolicies = policiesToJson(filter(type, ric, service));
353         return new ResponseEntity<>(filteredPolicies, HttpStatus.OK);
354     }
355
356     @GetMapping(path = Consts.V2_API_ROOT + "/policy-ids", produces = MediaType.APPLICATION_JSON_VALUE)
357     @ApiOperation(value = "Query policies, only policy identities are returned", notes = GET_POLICIES_QUERY_DETAILS)
358     @ApiResponses(value = { //
359             @ApiResponse(code = 200, message = "Policy identities", response = PolicyIdList.class), @ApiResponse(
360                     code = 404, message = "Near-RT RIC or type not found", response = ErrorResponse.ErrorInfo.class)})
361     public ResponseEntity<Object> getPolicyIds( //
362             @ApiParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false,
363                     value = "The identity of the policy type to get policies for.") //
364             @RequestParam(name = Consts.POLICY_TYPE_ID_PARAM, required = false) String policyTypeId, //
365             @ApiParam(name = Consts.RIC_ID_PARAM, required = false,
366                     value = "The identity of the Near-RT RIC to get policies for.") //
367             @RequestParam(name = Consts.RIC_ID_PARAM, required = false) String ricId, //
368             @ApiParam(name = Consts.SERVICE_ID_PARAM, required = false,
369                     value = "The identity of the service to get policies for.") //
370             @RequestParam(name = Consts.SERVICE_ID_PARAM, required = false) String serviceId) //
371     {
372         if ((policyTypeId != null && this.policyTypes.get(policyTypeId) == null)) {
373             return ErrorResponse.create("Policy type not found", HttpStatus.NOT_FOUND);
374         }
375         if ((ricId != null && this.rics.get(ricId) == null)) {
376             return ErrorResponse.create("Near-RT RIC not found", HttpStatus.NOT_FOUND);
377         }
378
379         String policyIdsJson = toPolicyIdsJson(filter(policyTypeId, ricId, serviceId));
380         return new ResponseEntity<>(policyIdsJson, HttpStatus.OK);
381     }
382
383     @GetMapping(path = Consts.V2_API_ROOT + "/policy-status", produces = MediaType.APPLICATION_JSON_VALUE)
384     @ApiOperation(value = "Returns a policy status") //
385     @ApiResponses(value = { //
386             @ApiResponse(code = 200, message = "Policy status", response = JsonObject.class), //
387             @ApiResponse(code = 404, message = "Policy is not found", response = ErrorResponse.ErrorInfo.class)} //
388     )
389     public Mono<ResponseEntity<Object>> getPolicyStatus( //
390             @ApiParam(name = Consts.POLICY_ID_PARAM, required = true, value = "The identity of the policy.") //
391             @RequestParam(name = Consts.POLICY_ID_PARAM, required = true) String policyId) {
392         try {
393             Policy policy = policies.getPolicy(policyId);
394
395             return a1ClientFactory.createA1Client(policy.ric()) //
396                     .flatMap(client -> client.getPolicyStatus(policy)) //
397                     .flatMap(status -> Mono.just(new ResponseEntity<>((Object) status, HttpStatus.OK)))
398                     .onErrorResume(this::handleException);
399         } catch (ServiceException e) {
400             return ErrorResponse.createMono(e, HttpStatus.NOT_FOUND);
401         }
402     }
403
404     private void keepServiceAlive(String name) {
405         Service s = this.services.get(name);
406         if (s != null) {
407             s.keepAlive();
408         }
409     }
410
411     private boolean include(String filter, String value) {
412         return filter == null || value.equals(filter);
413     }
414
415     private Collection<Policy> filter(Collection<Policy> collection, String type, String ric, String service) {
416         if (type == null && ric == null && service == null) {
417             return collection;
418         }
419         List<Policy> filtered = new ArrayList<>();
420         for (Policy p : collection) {
421             if (include(type, p.type().id()) && include(ric, p.ric().id()) && include(service, p.ownerServiceId())) {
422                 filtered.add(p);
423             }
424         }
425         return filtered;
426     }
427
428     private Collection<Policy> filter(String type, String ric, String service) {
429         if (type != null) {
430             return filter(policies.getForType(type), null, ric, service);
431         } else if (service != null) {
432             return filter(policies.getForService(service), type, ric, null);
433         } else if (ric != null) {
434             return filter(policies.getForRic(ric), type, null, service);
435         } else {
436             return policies.getAll();
437         }
438     }
439
440     private String policiesToJson(Collection<Policy> policies) {
441         List<PolicyInfo> v = new ArrayList<>(policies.size());
442         for (Policy p : policies) {
443             PolicyInfo policyInfo = new PolicyInfo();
444             policyInfo.policyId = p.id();
445             policyInfo.policyData = fromJson(p.json());
446             policyInfo.ricId = p.ric().id();
447             policyInfo.policyTypeId = p.type().id();
448             policyInfo.serviceId = p.ownerServiceId();
449             policyInfo.lastModified = p.lastModified().toString();
450             if (!policyInfo.validate()) {
451                 logger.error("BUG, all fields must be set");
452             }
453             v.add(policyInfo);
454         }
455         PolicyInfoList list = new PolicyInfoList(v);
456         return gson.toJson(list);
457     }
458
459     private Object fromJson(String jsonStr) {
460         return gson.fromJson(jsonStr, Object.class);
461     }
462
463     private String toPolicyTypeSchemasJson(Collection<PolicyType> types) {
464
465         Collection<String> schemas = new ArrayList<>();
466         for (PolicyType t : types) {
467             schemas.add(t.schema());
468         }
469         PolicySchemaList res = new PolicySchemaList(schemas);
470         return gson.toJson(res);
471     }
472
473     private String toPolicyTypeIdsJson(Collection<PolicyType> types) {
474         List<String> v = new ArrayList<>(types.size());
475         for (PolicyType t : types) {
476             v.add(t.id());
477         }
478         PolicyTypeIdList ids = new PolicyTypeIdList(v);
479         return gson.toJson(ids);
480     }
481
482     private String toPolicyIdsJson(Collection<Policy> policies) {
483         List<String> v = new ArrayList<>(policies.size());
484         for (Policy p : policies) {
485             v.add(p.id());
486         }
487         return gson.toJson(new PolicyIdList(v));
488     }
489
490 }