1 files changed, 79 insertions, 0 deletions
diff --git a/participant/participant-impl/participant-impl-policy/src/main/java/org/onap/policy/clamp/controlloop/participant/policy/main/parameters/ParticipantPolicyParameterHandler.java b/participant/participant-impl/participant-impl-policy/src/main/java/org/onap/policy/clamp/controlloop/participant/policy/main/parameters/ParticipantPolicyParameterHandler.java
new file mode 100644
index 000000000..98cea821a
--- /dev/null
+++ b/participant/participant-impl/participant-impl-policy/src/main/java/org/onap/policy/clamp/controlloop/participant/policy/main/parameters/ParticipantPolicyParameterHandler.java
@@ -0,0 +1,79 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2021 Nordix Foundation.
+ * ================================================================================
+ * 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.clamp.controlloop.participant.policy.main.parameters;
+
+import java.io.File;
+import javax.ws.rs.core.Response;
+import org.onap.policy.clamp.controlloop.common.exception.ControlLoopException;
+import org.onap.policy.clamp.controlloop.participant.policy.main.startstop.ParticipantPolicyCommandLineArguments;
+import org.onap.policy.common.parameters.ValidationResult;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+
+/**
+ * This class handles reading, parsing and validating of policy participant parameters from JSON files.
+ */
+public class ParticipantPolicyParameterHandler {
+
+    private static final Coder CODER = new StandardCoder();
+
+    /**
+     * Read the parameters from the parameter file.
+     *
+     * @param arguments the arguments passed to policy
+     * @return the parameters read from the configuration file
+     * @throws ControlLoopException on parameter exceptions
+     */
+    public ParticipantPolicyParameters getParameters(final ParticipantPolicyCommandLineArguments arguments)
+            throws ControlLoopException {
+        ParticipantPolicyParameters parameters = null;
+
+        // Read the parameters
+        try {
+            // Read the parameters from JSON
+            File file = new File(arguments.getFullConfigurationFilePath());
+            parameters = CODER.decode(file, ParticipantPolicyParameters.class);
+        } catch (final CoderException e) {
+            final String errorMessage = "error reading parameters from \"" + arguments.getConfigurationFilePath()
+                    + "\"\n" + "(" + e.getClass().getSimpleName() + ")";
+            throw new ControlLoopException(Response.Status.NOT_ACCEPTABLE, errorMessage, e);
+        }
+
+        // The JSON processing returns null if there is an empty file
+        if (parameters == null) {
+            final String errorMessage = "no parameters found in \"" + arguments.getConfigurationFilePath() + "\"";
+            throw new ControlLoopException(Response.Status.NOT_ACCEPTABLE, errorMessage);
+        }
+
+        // validate the parameters
+        final ValidationResult validationResult = parameters.validate();
+        if (!validationResult.isValid()) {
+            String returnMessage =
+                    "validation error(s) on parameters from \"" + arguments.getConfigurationFilePath() + "\"\n";
+            returnMessage += validationResult.getResult();
+
+            throw new ControlLoopException(Response.Status.NOT_ACCEPTABLE, returnMessage);
+        }
+
+        return parameters;
+    }
+}