ReferenceResolver.java
/*
* The contents of this file are subject to the terms of the Common Development and
* Distribution License (the License). You may not use this file except in compliance with the
* License.
*
* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
* specific language governing permission and limitations under the License.
*
* When distributing Covered Software, include this CDDL Header Notice in each file and include
* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
* Header, with the fields enclosed by brackets [] replaced by your own identifying
* information: "Portions copyright [year] [name of copyright owner]".
*
* Copyright 2016 ForgeRock AS.
*/
package org.forgerock.api.util;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.forgerock.api.models.ApiDescription;
import org.forgerock.api.models.ApiError;
import org.forgerock.api.models.Reference;
import org.forgerock.api.models.Resource;
import org.forgerock.api.models.Schema;
import org.forgerock.util.Reject;
/**
* Helper that registers one or more {@link ApiDescription} instances and provides a means to resolve
* {@link Reference}s.
*/
public class ReferenceResolver {
private static final String DEFINITIONS_REF = "#/definitions/";
private static final String ERRORS_REF = "#/errors/";
private static final String SERVICES_REF = "#/services/";
private final ApiDescription local;
private final Map<String, ApiDescription> map;
/**
* Creates a reference-resolver and defines the one {@link ApiDescription} that can be used for local
* (non-namespaced) reference lookups.
*
* @param local {@link ApiDescription} to use for local (non-namespaced) reference lookups
*/
public ReferenceResolver(final ApiDescription local) {
this.local = Reject.checkNotNull(local);
map = new HashMap<>();
register(local);
}
/**
* Registers an external {@link ApiDescription}, for {@link org.forgerock.api.models.Reference} lookup, and
* must not have previously been registered.
*
* @param apiDescription {@link ApiDescription} to register, which has not previously been registered
* @return self
*/
public ReferenceResolver register(final ApiDescription apiDescription) {
if (map.containsKey(apiDescription.getId())) {
throw new IllegalStateException("Already registered ID = " + apiDescription.getId());
}
map.put(apiDescription.getId(), apiDescription);
return this;
}
/**
* Registers external {@link ApiDescription}s, for {@link org.forgerock.api.models.Reference} lookup, and each
* must not have previously been registered.
*
* @param apiDescriptions List of {@link ApiDescription}s to register, which have not previously been registered
* @return self
*/
public ReferenceResolver registerAll(final ApiDescription... apiDescriptions) {
for (final ApiDescription item : apiDescriptions) {
register(item);
}
return this;
}
/**
* Gets a {@link org.forgerock.api.models.Definitions} {@link Schema} by JSON reference.
*
* @param reference JSON reference
* @return {@link Schema} or {@code null} if not found
*/
public Schema getDefinition(final Reference reference) {
return resolveDefinition(reference, new HashSet<String>());
}
private Schema resolveDefinition(final Reference reference, final Set<String> visitedRefs) {
final int nameStart = reference.getValue().indexOf(DEFINITIONS_REF);
if (nameStart != -1) {
final String name = reference.getValue().substring(nameStart + DEFINITIONS_REF.length());
if (!name.isEmpty()) {
if (!visitedRefs.add(reference.getValue())) {
throw new IllegalStateException("Reference loop detected: " + reference.getValue());
}
if (nameStart == 0) {
// there is no namespace, so do a local lookup
if (local.getDefinitions() != null) {
final Schema schema = local.getDefinitions().get(name);
if (schema != null && schema.getReference() != null) {
// reference chain
return resolveDefinition(schema.getReference(), visitedRefs);
}
return schema;
}
} else {
final String namespace = reference.getValue().substring(0, nameStart);
final ApiDescription apiDescription = map.get(namespace);
if (apiDescription != null && apiDescription.getDefinitions() != null) {
final Schema schema = apiDescription.getDefinitions().get(name);
if (schema != null && schema.getReference() != null) {
// reference chain
return resolveDefinition(schema.getReference(), visitedRefs);
}
return schema;
}
}
}
}
return null;
}
/**
* Gets and {@link org.forgerock.api.models.Errors} {@link ApiError} by JSON reference.
*
* @param reference JSON reference
* @return {@link ApiError} or {@code null} if not found
*/
public ApiError getError(final Reference reference) {
return resolveError(reference, new HashSet<String>());
}
private ApiError resolveError(final Reference reference, final Set<String> visitedRefs) {
final int nameStart = reference.getValue().indexOf(ERRORS_REF);
if (nameStart != -1) {
final String name = reference.getValue().substring(nameStart + ERRORS_REF.length());
if (!name.isEmpty()) {
if (!visitedRefs.add(reference.getValue())) {
throw new IllegalStateException("Reference loop detected: " + reference.getValue());
}
if (nameStart == 0) {
// there is no namespace, so do a local lookup
if (local.getErrors() != null) {
final ApiError error = local.getErrors().get(name);
if (error != null && error.getReference() != null) {
// reference chain
return resolveError(error.getReference(), visitedRefs);
}
return error;
}
} else {
final String namespace = reference.getValue().substring(0, nameStart);
final ApiDescription apiDescription = map.get(namespace);
if (apiDescription != null && apiDescription.getErrors() != null) {
final ApiError error = apiDescription.getErrors().get(name);
if (error != null && error.getReference() != null) {
// reference chain
return resolveError(error.getReference(), visitedRefs);
}
return error;
}
}
}
}
return null;
}
/**
* Get a {@link org.forgerock.api.models.Services} {@link Resource} by JSON reference.
*
* @param reference JSON reference
* @return {@link Resource} or {@code null} if not found
*/
public Resource getService(final Reference reference) {
return resolveService(reference, new HashSet<String>());
}
private Resource resolveService(final Reference reference, final Set<String> visitedRefs) {
final int nameStart = reference.getValue().indexOf(SERVICES_REF);
if (nameStart != -1) {
final String name = reference.getValue().substring(nameStart + SERVICES_REF.length());
if (!name.isEmpty()) {
if (!visitedRefs.add(reference.getValue())) {
throw new IllegalStateException("Reference loop detected: " + reference.getValue());
}
if (nameStart == 0) {
// there is no namespace, so do a local lookup
if (local.getServices() != null) {
final Resource service = local.getServices().get(name);
if (service != null && service.getReference() != null) {
// reference chain
return resolveService(service.getReference(), visitedRefs);
}
return service;
}
} else {
final String namespace = reference.getValue().substring(0, nameStart);
final ApiDescription apiDescription = map.get(namespace);
if (apiDescription != null && apiDescription.getServices() != null) {
final Resource service = apiDescription.getServices().get(name);
if (service != null && service.getReference() != null) {
// reference chain
return resolveService(service.getReference(), visitedRefs);
}
return service;
}
}
}
}
return null;
}
}