add HttpEntityFactory (android-async-http#1333)

Author: saeed-rz

library/src/main/java/com/loopj/android/http/HttpEntityFactory.java

@@ -0,0 +1,66 @@
+package com.loopj.android.http;
+
+import com.loopj.android.http.interfaces.RequestParamInterface;
+import com.loopj.android.http.interfaces.RequestParamsInterface;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import cz.msebera.android.httpclient.HttpEntity;
+import cz.msebera.android.httpclient.NameValuePair;
+import cz.msebera.android.httpclient.client.entity.EntityBuilder;
+import cz.msebera.android.httpclient.client.entity.UrlEncodedFormEntity;
+import cz.msebera.android.httpclient.message.BasicNameValuePair;
+import cz.msebera.android.httpclient.util.EntityUtils;
+
+public class HttpEntityFactory {
+
+    /**
+     * convert and mix @RequestParams and @HttpEntity into one @HttpEntity
+     * @param requestParams
+     * @param httpEntity
+     * @return
+     */
+    public static HttpEntity getHttpEntity(RequestParams requestParams, HttpEntity httpEntity) {
+        List<NameValuePair> pairs = new ArrayList<>();
+        for (Map.Entry<String, RequestParamInterface> param : requestParams.getParams()) {
+            pairs.add(new BasicNameValuePair(param.getKey(), param.getValue().getValue()));
+        }
+
+        String sEntity = "";
+        try {
+            sEntity = EntityUtils.toString(httpEntity);
+            sEntity = sEntity.concat(EntityUtils.toString(new UrlEncodedFormEntity(pairs)));
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        try {
+            return EntityBuilder.create().setText(sEntity).build();
+        } catch (Exception e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    /**
+     * get @UrlEncodedFormEntity from @RequestParams object
+     * @param params
+     * @return
+     */
+    public static HttpEntity getFormEntity(RequestParamsInterface params) {
+        List<NameValuePair> pairs = new ArrayList<NameValuePair>();
+        for (Map.Entry<String, RequestParamInterface> param : params.getParams()) {
+            pairs.add(new BasicNameValuePair(param.getKey(), param.getValue().getValue()));
+        }
+        try {
+            return new UrlEncodedFormEntity(pairs);
+        } catch (UnsupportedEncodingException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+}