Add velocity engine template service

Change-Id: Idde39b587b41328e5a5e2e32ab32c29cd27d4855
Issue-ID: CCSDK-941
Signed-off-by: Muthuramalingam, Brinda Santh <bs2796@att.com>

2 files changed, 107 insertions, 1 deletions

diff --git a/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/service/BluePrintTemplateService.kt b/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/service/BluePrintTemplateService.kt
new file mode 100644
index 00000000..d175fdde
--- /dev/null
+++ b/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/service/BluePrintTemplateService.kt
@@ -0,0 +1,94 @@
+/*
+ * Copyright © 2017-2018 AT&T Intellectual Property.
+ *
+ * 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.
+ */
+
+package org.onap.ccsdk.apps.controllerblueprints.core.service
+
+import com.fasterxml.jackson.core.io.CharTypes
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.node.JsonNodeFactory
+import com.fasterxml.jackson.databind.node.TextNode
+import org.apache.commons.lang3.BooleanUtils
+import org.apache.commons.lang3.StringUtils
+import org.apache.velocity.VelocityContext
+import org.apache.velocity.app.Velocity
+import org.onap.ccsdk.apps.controllerblueprints.core.BluePrintProcessorException
+import org.onap.ccsdk.apps.controllerblueprints.core.utils.JacksonUtils
+import java.io.StringWriter
+
+open class BluePrintTemplateService {
+
+    companion object {
+
+        /**
+         * Generate Content from Velocity Template and JSON Content.
+         */
+        fun generateContent(template: String, json: String,
+                            ignoreJsonNull: Boolean = false,
+                            additionalContext: MutableMap<String, Any> = hashMapOf()): String {
+            Velocity.init()
+            val mapper = ObjectMapper()
+            val nodeFactory = BluePrintJsonNodeFactory()
+            mapper.setNodeFactory(nodeFactory)
+
+            val jsonNode = mapper.readValue<JsonNode>(json, JsonNode::class.java)
+                    ?: throw BluePrintProcessorException("couldn't get json node from json")
+
+            if (ignoreJsonNull)
+                JacksonUtils.removeJsonNullNode(jsonNode)
+
+            val velocityContext = VelocityContext()
+            velocityContext.put("StringUtils", StringUtils::class.java)
+            velocityContext.put("BooleanUtils", BooleanUtils::class.java)
+            /**
+             * Add the Custom Velocity Context API
+             */
+            additionalContext.forEach { name, value -> velocityContext.put(name, value) }
+            /**
+             * Add the JSON Data to the context
+             */
+            jsonNode.fields().forEach { entry ->
+                velocityContext.put(entry.key, entry.value)
+            }
+
+            val stringWriter = StringWriter()
+            Velocity.evaluate(velocityContext, stringWriter, "TemplateData", template)
+            stringWriter.flush()
+            return stringWriter.toString()
+        }
+    }
+}
+
+/**
+ * Customise JsonNodeFactory adn TextNode, Since it introduces quotes for string data.
+ */
+open class BluePrintJsonNodeFactory : JsonNodeFactory() {
+    override fun textNode(text: String): TextNode {
+        return BluePrintTextNode(text)
+    }
+}
+
+open class BluePrintTextNode(v: String) : TextNode(v) {
+    override fun toString(): String {
+        var len = this._value.length
+        len = len + 2 + (len shr 4)
+        val sb = StringBuilder(len)
+        CharTypes.appendQuoted(sb, this._value)
+        return sb.toString()
+    }
+
+}
+
diff --git a/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/utils/JacksonUtils.kt b/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/utils/JacksonUtils.kt
index 58a82079..6321a838 100644
--- a/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/utils/JacksonUtils.kt
+++ b/components/core/src/main/kotlin/org/onap/ccsdk/apps/controllerblueprints/core/utils/JacksonUtils.kt
@@ -21,10 +21,10 @@ import com.att.eelf.configuration.EELFManager
 import com.fasterxml.jackson.annotation.JsonInclude

 import com.fasterxml.jackson.core.type.TypeReference

 import com.fasterxml.jackson.databind.JsonNode

+import com.fasterxml.jackson.databind.SerializationFeature

 import com.fasterxml.jackson.databind.node.ArrayNode

 import com.fasterxml.jackson.databind.node.NullNode

 import com.fasterxml.jackson.databind.node.ObjectNode

-import com.fasterxml.jackson.databind.SerializationFeature

 import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper

 import kotlinx.coroutines.Dispatchers

 import kotlinx.coroutines.async

@@ -56,6 +56,18 @@ class JacksonUtils {
             return jacksonObjectMapper().treeToValue(node, valueType)

         }

 

+        fun removeJsonNullNode(node: JsonNode) {

+            val it = node.iterator()

+            while (it.hasNext()) {

+                val child = it.next()

+                if (child.isNull) {

+                    it.remove()

+                } else {

+                    removeJsonNullNode(child)

+                }

+            }

+        }

+

         fun getContent(fileName: String): String = runBlocking {

             async {

                 try {