Get policy type from policy-api

Added a class to retrieve a policy type from the policy-api.
Updated property files to include parameters that are needed
to configure it.
Updates per review comments:
- change PolicyApi to PolicyApiCaller
- use HttpClientFactory
- removed superfluous constructors from exception classes
- changed parameters to use RestServerParameters instead of BusTopicParams

Change-Id: I8aad6ca5a733c8ad9cc983496e745ebe7400dd17
Issue-ID: POLICY-1911
Signed-off-by: Jim Hahn <jrh3@att.com>

3 files changed, 187 insertions, 0 deletions

diff --git a/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/NotFoundException.java b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/NotFoundException.java
new file mode 100644
index 00000000..260d16f2
--- /dev/null
+++ b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/NotFoundException.java
@@ -0,0 +1,41 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.pdp.xacml.application.common;
+
+/**
+ * Exception indicating that the data of interest was not found when querying the
+ * policy-api.
+ */
+public class NotFoundException extends PolicyApiException {
+    private static final long serialVersionUID = 1L;
+
+    public NotFoundException(String message) {
+        super(message);
+    }
+
+    public NotFoundException(Throwable cause) {
+        super(cause);
+    }
+
+    public NotFoundException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
diff --git a/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiCaller.java b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiCaller.java
new file mode 100644
index 00000000..9d47517a
--- /dev/null
+++ b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiCaller.java
@@ -0,0 +1,106 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.pdp.xacml.application.common;
+
+import java.net.HttpURLConnection;
+import javax.ws.rs.core.Response;
+import org.onap.policy.common.endpoints.event.comm.bus.internal.BusTopicParams;
+import org.onap.policy.common.endpoints.http.client.HttpClient;
+import org.onap.policy.common.endpoints.http.client.HttpClientConfigException;
+import org.onap.policy.common.endpoints.http.client.HttpClientFactoryInstance;
+import org.onap.policy.common.endpoints.parameters.RestServerParameters;
+import org.onap.policy.common.gson.GsonMessageBodyHandler;
+import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyType;
+import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyTypeIdentifier;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Methods to access policy-api via REST service calls.
+ */
+public class PolicyApiCaller {
+    private static Logger logger = LoggerFactory.getLogger(PolicyApiCaller.class);
+
+    private static final String POLICY_TYPE_URI = "/policy/api/v1/policytypes/";
+    private static final String POLICY_TYPE_VERSION_URI = "/versions/";
+
+    private final HttpClient httpClient;
+
+    /**
+     * Constructs the object.
+     *
+     * @param params target specification
+     * @throws PolicyApiException if an error occurs
+     */
+    public PolicyApiCaller(RestServerParameters params) throws PolicyApiException {
+        BusTopicParams busParams = new BusTopicParams();
+        busParams.setClientName("policy-api");
+        busParams.setHostname(params.getHost());
+        busParams.setManaged(false);
+        busParams.setPassword(params.getPassword());
+        busParams.setPort(params.getPort());
+        busParams.setSerializationProvider(GsonMessageBodyHandler.class.getName());
+        busParams.setUseHttps(params.isHttps());
+        busParams.setUserName(params.getUserName());
+
+        try {
+            httpClient = makeClient(busParams);
+        } catch (HttpClientConfigException e) {
+            throw new PolicyApiException("connection to host: " + busParams.getHostname(), e);
+        }
+    }
+
+    /**
+     * Gets a policy type from policy-api.
+     *
+     * @param type policy type of interest
+     * @return the desired policy type
+     * @throws PolicyApiException if an error occurs
+     */
+    public ToscaPolicyType getPolicyType(ToscaPolicyTypeIdentifier type) throws PolicyApiException {
+
+        try {
+            Response resp = httpClient
+                            .get(POLICY_TYPE_URI + type.getName() + POLICY_TYPE_VERSION_URI + type.getVersion());
+
+            switch (resp.getStatus()) {
+                case HttpURLConnection.HTTP_OK:
+                    return resp.readEntity(ToscaPolicyType.class);
+                case HttpURLConnection.HTTP_NOT_FOUND:
+                    logger.warn("policy-api not found {}", resp);
+                    throw new NotFoundException(type.toString());
+                default:
+                    logger.warn("policy-api request error {}", resp);
+                    throw new PolicyApiException(type.toString());
+            }
+
+        } catch (RuntimeException e) {
+            logger.warn("policy-api connection error");
+            throw new PolicyApiException(type.toString(), e);
+        }
+    }
+
+    // these methods may be overridden by junit tests
+
+    protected HttpClient makeClient(BusTopicParams busParams) throws HttpClientConfigException {
+        return HttpClientFactoryInstance.getClientFactory().build(busParams);
+    }
+}
diff --git a/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiException.java b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiException.java
new file mode 100644
index 00000000..380bd19a
--- /dev/null
+++ b/applications/common/src/main/java/org/onap/policy/pdp/xacml/application/common/PolicyApiException.java
@@ -0,0 +1,40 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.pdp.xacml.application.common;
+
+/**
+ * Exception occurring while accessing the policy-api.
+ */
+public class PolicyApiException extends Exception {
+    private static final long serialVersionUID = 1L;
+
+    public PolicyApiException(String message) {
+        super(message);
+    }
+
+    public PolicyApiException(Throwable cause) {
+        super(cause);
+    }
+
+    public PolicyApiException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}