Adding policy decoder to extract file from csar

* Adding decoder configuration parameters infrastructure to support
plugin based architecture. Adding a new policy decoder after this will be just
creating a new decoder class and its corresponding parameter class.

* Adding a new decoder which extracts policy file from given csar. It is
written in a generic way to extract file for any pdp like apex, drools.

* Adding configuration parameters for the new decoder. The policy file name and
policy type is passed as parameter to the decoder.

* Fixing few broken package declaration in pdpx decoder tests.
* Adding test cases for all code changes.

Change-Id: I95e68cebce0f9747ca63b090f9b9116ce8836939
Issue-ID: POLICY-1101
Signed-off-by: ramverma <ram.krishna.verma@ericsson.com>

7 files changed, 159 insertions, 2 deletions

diff --git a/reception/src/main/java/org/onap/policy/distribution/reception/decoding/PolicyDecoder.java b/reception/src/main/java/org/onap/policy/distribution/reception/decoding/PolicyDecoder.java
index 2a07ec72..9cd660a9 100644
--- a/reception/src/main/java/org/onap/policy/distribution/reception/decoding/PolicyDecoder.java
+++ b/reception/src/main/java/org/onap/policy/distribution/reception/decoding/PolicyDecoder.java
@@ -34,6 +34,14 @@ import org.onap.policy.distribution.model.PolicyInput;
 public interface PolicyDecoder<S extends PolicyInput, T extends Policy> {
 
     /**
+     * Configure the policy decoder. This method will be invoked immediately after instantiation in order for the policy
+     * decoder to configure itself.
+     *
+     * @param parameterGroupName the name of the parameter group which contains the configuration for the policy decoder
+     */
+    void configure(String parameterGroupName);
+
+    /**
      * Can the decoder handle input of the specified type.
      *
      * @param policyInput the type
diff --git a/reception/src/main/java/org/onap/policy/distribution/reception/handling/PluginHandler.java b/reception/src/main/java/org/onap/policy/distribution/reception/handling/PluginHandler.java
index e6bfefea..74b8eb16 100644
--- a/reception/src/main/java/org/onap/policy/distribution/reception/handling/PluginHandler.java
+++ b/reception/src/main/java/org/onap/policy/distribution/reception/handling/PluginHandler.java
@@ -92,6 +92,7 @@ public class PluginHandler {
                         (Class<PolicyDecoder<PolicyInput, Policy>>) Class
                                 .forName(decoderParameters.getDecoderClassName());
                 final PolicyDecoder<PolicyInput, Policy> decoder = policyDecoderClass.newInstance();
+                decoder.configure(decoderParameters.getDecoderConfigurationName());
                 policyDecoders.add(decoder);
             } catch (final ClassNotFoundException | InstantiationException | IllegalAccessException exp) {
                 LOGGER.error("exception occured while initializing decoders", exp);
diff --git a/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParameterGroup.java b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParameterGroup.java
new file mode 100644
index 00000000..00ae0a3a
--- /dev/null
+++ b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParameterGroup.java
@@ -0,0 +1,45 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. 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.distribution.reception.parameters;
+
+import org.onap.policy.common.parameters.ParameterGroup;
+import org.onap.policy.distribution.reception.decoding.PolicyDecoder;
+
+/**
+ * Base class of all {@link ParameterGroup} classes for configuration parameters for {@link PolicyDecoder} classes.
+ *
+ * @author Ram Krishna Verma (ram.krishna.verma@ericsson.com)
+ */
+public abstract class PolicyDecoderConfigurationParameterGroup implements ParameterGroup {
+
+    private String name;
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void setName(final String name) {
+        this.name = name;
+    }
+
+}
diff --git a/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParametersJsonAdapter.java b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParametersJsonAdapter.java
new file mode 100644
index 00000000..64eb4ed7
--- /dev/null
+++ b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderConfigurationParametersJsonAdapter.java
@@ -0,0 +1,84 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. 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.distribution.reception.parameters;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonPrimitive;
+
+import java.lang.reflect.Type;
+
+import org.slf4j.ext.XLogger;
+import org.slf4j.ext.XLoggerFactory;
+
+/**
+ * This class deserialises policy decoder parameters from JSON.
+ *
+ * @author Ram Krishna Verma (ram.krishna.verma@ericsson.com)
+ */
+public class PolicyDecoderConfigurationParametersJsonAdapter
+        implements JsonDeserializer<PolicyDecoderConfigurationParameterGroup> {
+    private static final XLogger LOGGER =
+            XLoggerFactory.getXLogger(PolicyDecoderConfigurationParametersJsonAdapter.class);
+
+    private static final String PARAMETER_CLASS_NAME = "parameterClassName";
+    private static final String POLICY_DECODER_PARAMETERS = "parameters";
+
+    @Override
+    public PolicyDecoderConfigurationParameterGroup deserialize(final JsonElement json, final Type typeOfT,
+            final JsonDeserializationContext context) {
+        final JsonObject jsonObject = json.getAsJsonObject();
+
+        final String policyDecoderParameterClassName = getParameterGroupClassName(jsonObject);
+        final Class<?> policyDecoderParameterClass = getParameterGroupClass(policyDecoderParameterClassName);
+
+        return context.deserialize(jsonObject.get(POLICY_DECODER_PARAMETERS), policyDecoderParameterClass);
+    }
+
+    private String getParameterGroupClassName(final JsonObject jsonObject) {
+        final JsonPrimitive classNameJsonPrimitive = ((JsonPrimitive) jsonObject.get(PARAMETER_CLASS_NAME));
+
+        if (classNameJsonPrimitive == null || classNameJsonPrimitive.getAsString().length() == 0) {
+            final String errorMessage = "parameter \"" + PARAMETER_CLASS_NAME + "\" value \""
+                    + (classNameJsonPrimitive != null ? classNameJsonPrimitive.getAsString() : "null")
+                    + "\" invalid in JSON file";
+            LOGGER.warn(errorMessage);
+            throw new IllegalArgumentException(errorMessage);
+        }
+        return classNameJsonPrimitive.getAsString().replaceAll("\\s+", "");
+    }
+
+    private Class<?> getParameterGroupClass(final String policyDecoderParameterClassName) {
+        Class<?> policyDecoderParameterClass = null;
+        try {
+            policyDecoderParameterClass = Class.forName(policyDecoderParameterClassName);
+        } catch (final ClassNotFoundException exp) {
+            final String errorMessage = "parameter \"" + PARAMETER_CLASS_NAME + "\" value \""
+                    + policyDecoderParameterClassName + "\", could not find class";
+            LOGGER.warn(errorMessage, exp);
+            throw new IllegalArgumentException(errorMessage, exp);
+        }
+        return policyDecoderParameterClass;
+    }
+
+}
diff --git a/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderParameters.java b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderParameters.java
index 0b7ae0b7..91ada5ff 100644
--- a/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderParameters.java
+++ b/reception/src/main/java/org/onap/policy/distribution/reception/parameters/PolicyDecoderParameters.java
@@ -37,16 +37,20 @@ public class PolicyDecoderParameters implements ParameterGroup {
 
     private String decoderType;
     private String decoderClassName;
+    private String decoderConfigurationName;
 
     /**
      * Constructor for instantiating PolicyDecoderParameters.
      *
      * @param decoderType the policy decoder type
      * @param decoderClassName the policy decoder class name
+     * @param decoderConfigurationName the policy decoder configuration name
      */
-    public PolicyDecoderParameters(final String decoderType, final String decoderClassName) {
+    public PolicyDecoderParameters(final String decoderType, final String decoderClassName,
+            final String decoderConfigurationName) {
         this.decoderType = decoderType;
         this.decoderClassName = decoderClassName;
+        this.decoderConfigurationName = decoderConfigurationName;
     }
 
     /**
@@ -68,6 +72,15 @@ public class PolicyDecoderParameters implements ParameterGroup {
     }
 
     /**
+     * Return the name of the decoder configuration of this {@link PolicyDecoderParameters} instance.
+     *
+     * @return the the name of the decoder configuration
+     */
+    public String getDecoderConfigurationName() {
+        return decoderConfigurationName;
+    }
+
+    /**
      * {@inheritDoc}
      */
     @Override
diff --git a/reception/src/test/java/org/onap/policy/distribution/reception/handling/AbstractReceptionHandlerTest.java b/reception/src/test/java/org/onap/policy/distribution/reception/handling/AbstractReceptionHandlerTest.java
index d339507c..8dc84621 100644
--- a/reception/src/test/java/org/onap/policy/distribution/reception/handling/AbstractReceptionHandlerTest.java
+++ b/reception/src/test/java/org/onap/policy/distribution/reception/handling/AbstractReceptionHandlerTest.java
@@ -29,6 +29,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+
 import org.junit.Test;
 import org.onap.policy.common.parameters.ParameterService;
 import org.onap.policy.distribution.forwarding.PolicyForwarder;
@@ -57,6 +58,7 @@ public class AbstractReceptionHandlerTest {
     private static final String FORWARDER_CLASS_NAME =
             "org.onap.policy.distribution.reception.handling.DummyPolicyForwarder";
     private static final String FORWARDER_CONFIGURATION_PARAMETERS = "DummyConfiguration";
+    private static final String DECODER_CONFIGURATION_PARAMETERS = "DummyDecoderConfiguration";
 
     @Test
     public void testInputReceived() throws PolicyDecodingException, NoSuchFieldException, SecurityException,
@@ -171,7 +173,8 @@ public class AbstractReceptionHandlerTest {
 
     private Map<String, PolicyDecoderParameters> getPolicyDecoders() {
         final Map<String, PolicyDecoderParameters> policyDecoders = new HashMap<String, PolicyDecoderParameters>();
-        final PolicyDecoderParameters pDParameters = new PolicyDecoderParameters(DECODER_TYPE, DECODER_CLASS_NAME);
+        final PolicyDecoderParameters pDParameters =
+                new PolicyDecoderParameters(DECODER_TYPE, DECODER_CLASS_NAME, DECODER_CONFIGURATION_PARAMETERS);
         policyDecoders.put(DECODER_KEY, pDParameters);
         return policyDecoders;
     }
diff --git a/reception/src/test/java/org/onap/policy/distribution/reception/handling/DummyDecoder.java b/reception/src/test/java/org/onap/policy/distribution/reception/handling/DummyDecoder.java
index 2de1737e..74792b1e 100644
--- a/reception/src/test/java/org/onap/policy/distribution/reception/handling/DummyDecoder.java
+++ b/reception/src/test/java/org/onap/policy/distribution/reception/handling/DummyDecoder.java
@@ -56,4 +56,7 @@ public class DummyDecoder implements PolicyDecoder<PolicyInput, Policy> {
     public Collection<Policy> decode(final PolicyInput input) throws PolicyDecodingException {
         return policesToReturn;
     }
+
+    @Override
+    public void configure(final String parameterGroupName) {}
 }