Feat/dx 746 variants implementation

contentstack/build.gradle

@@ -10,7 +10,7 @@ android.buildFeatures.buildConfig true
 mavenPublishing {
     publishToMavenCentral(SonatypeHost.DEFAULT)
     signAllPublications()
-    coordinates("com.contentstack.sdk", "android", "3.16.1")
+    coordinates("com.contentstack.sdk", "android", "4.0.0")
 
     pom {
         name = "contentstack-android"
@@ -112,18 +112,27 @@ android {
 
     def localProperties = new Properties()
     localProperties.load(new FileInputStream(rootProject.file("local.properties")))
+    def getPropertyOrEmpty = { key ->
+        def value = localProperties.getProperty(key)
+        return value != null ? "$value" : "\"\""
+    }
+    def variantsArray = localProperties.getProperty('variantsUID')?.split(",")?.collect { it.trim() }
+    def variantsAsArrayString = variantsArray ? 'new String[] {' + variantsArray.collect { "\"$it\"" }.join(", ") + '}' : "new String[0]"
     buildTypes {
         debug {
             debuggable true
             testCoverageEnabled true
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
 
-           buildConfigField "String", "host", localProperties['host']
-           buildConfigField "String", "APIKey", localProperties['APIKey']
-           buildConfigField "String", "deliveryToken", localProperties['deliveryToken']
-           buildConfigField "String", "environment", localProperties['environment']
-           buildConfigField "String", "contentTypeUID", localProperties['contentType']
-           buildConfigField "String", "assetUID", localProperties['assetUid']
+            buildConfigField "String", "host", getPropertyOrEmpty('host')
+            buildConfigField "String", "APIKey", getPropertyOrEmpty('APIKey')
+            buildConfigField "String", "deliveryToken", getPropertyOrEmpty('deliveryToken')
+            buildConfigField "String", "environment", getPropertyOrEmpty('environment')
+            buildConfigField "String", "contentTypeUID", getPropertyOrEmpty('contentType')
+            buildConfigField "String", "assetUID", getPropertyOrEmpty('assetUid')
+            buildConfigField "String", "variantUID", getPropertyOrEmpty('variantUID')
+            buildConfigField "String", "variantEntryUID", getPropertyOrEmpty('variantEntryUID')
+            buildConfigField "String[]", "variantsUID", variantsAsArrayString
         }
         release {
             minifyEnabled false

contentstack/src/androidTest/java/com/contentstack/sdk/EntryTestCase.java

@@ -27,6 +27,9 @@ public class EntryTestCase {
     private static final String CONTENT_TYPE_UID = BuildConfig.contentTypeUID;
     private static CountDownLatch latch;
     private static Stack stack;
+    private static String variantUID = BuildConfig.variantUID;
+    private static String variantEntryUID = BuildConfig.variantEntryUID;
+    private static String[] variantsUID = BuildConfig.variantsUID;
 
 
     @BeforeClass
@@ -319,4 +322,26 @@ public void onCompletion(ResponseType responseType, Error error) {
         latch.await();
     }
 
+    @Test
+    public void VariantsTestSingleUid(){
+        final Entry entry = stack.contentType("product").entry(variantEntryUID).variants(variantUID);
+        entry.fetch(new EntryResultCallBack() {
+            @Override
+            public void onCompletion(ResponseType responseType, Error error) {
+                assertEquals(variantUID, entry.getHeaders().get("x-cs-variant-uid"));
+                System.out.println(entry.toJSON());
+            }
+        });
+    }
+    @Test
+    public void VariantsTestArray(){
+        final Entry entry = stack.contentType("product").entry(variantEntryUID).variants(variantsUID);
+        entry.fetch(new EntryResultCallBack() {
+            @Override
+            public void onCompletion(ResponseType responseType, Error error) {
+                System.out.println(entry.toJSON());
+            }
+        });
+    }
+
 }

contentstack/src/main/java/com/contentstack/sdk/Entry.java

@@ -1494,4 +1494,40 @@ public Entry includeMetadata() {
         }
         return this;
     }
+    /**
+     * method variants
+     * memberof Entry
+     * description The variant header will be added to client
+     * returns {Entry}
+     * example
+     *          import contentstack from '@contentstack/delivery-sdk'
+     *
+     *          Stack stack = contentstack.Stack("apiKey", "deliveryToken",
+     *          "environment");
+     *          Entry entry =
+     *          stack.contentType("user").entry("entry_uid").variant("variant_uid").fetch();
+     */
+    public Entry variants(String variants){
+        if (variants != null && variants.length() > 0) {
+            this.localHeader.put("x-cs-variant-uid", variants.trim());
+        }
+        return this;
+
+    }
+    public Entry variants(String[] variants){
+        if (variants != null && variants.length > 0) {
+            List<String> variantList = new ArrayList<>();
+            for (String variant : variants) {
+                if(variant != null && !variant.trim().isEmpty())
+                    variantList.add(variant.trim());
+            }
+            if(!variantList.isEmpty()){
+                this.localHeader.put("x-cs-variant-uid", String.join(", ", variantList));
+            }
+        }
+        return this;
+    }
+    public ArrayMap<String, Object> getHeaders() {
+        return localHeader;
+    }
 }