add consumer support

README.adoc

@@ -15,15 +15,15 @@ In your Maven/Gradle project, first add the corresponding dependency:
 <dependency>
   <groupId>com.github.ozlerhakan</groupId>
   <artifactId>poiji</artifactId>
-  <version>1.13</version>
+  <version>1.14</version>
 </dependency>
 ----
 
 .gradle
 [source,groovy]
 ----
 dependencies {
-    compile 'com.github.ozlerhakan:poiji:1.13'
+    compile 'com.github.ozlerhakan:poiji:1.14'
 }
 ----
 
@@ -284,6 +284,59 @@ Car car = cars.get(0);
 // 4
 ----
 
+=== Example 4
+
+As of 1.14, Poiji supports Consumer Interface. As https://github.com/ozlerhakan/poiji/pull/39#issuecomment-409521808[@fmarazita] explained the usage, there are several benefits of having a Consumer:
+
+1. Huge excel file ( without you have all in memory)
+2. Run time processing/filtering data
+3. DB batch insertion
+
+For example, we have a Calculation entity class and want to insert each row while retrieving:
+
+[source, java]
+----
+class Calculation {
+
+  @ExcelCell(0)
+  String Name
+
+  @ExcelCell(1)
+  int a
+
+  @ExcelCell(2)
+  int b
+
+  public int getA(){
+    return a;
+  }
+
+  public int getB(){
+    return b;
+  }
+
+  public int getNanem){
+    return name;
+  }
+
+}
+----
+
+[source, java]
+----
+File fileCalculation = new File(example.xlsx);
+
+PoijiOptions options = PoijiOptionsBuilder.settings(1).sheetIndex(1).build();
+
+Poiji.fromExcel(fileCalculation, Calculation.class, options, this::dbInsertion);
+
+private void dbInsertion(Calculation siCalculation) {
+  int value= siCalculation.getA() + siCalculation.getB();
+  String name = siCalculation.getName();
+  return insertDB(name , value);
+}
+----
+
 === Try with JShell
 
 Since we have a new pedagogic tool, Java 9 REPL, you can try Poiji in JShell. Clone the repo and follow the steps below. JShell should open up a new jshell session once loading the startup scripts and the specified jars that must be in the classpath. You must first import and create related packages and classes before using Poiji. We are able to use directly Poiji and Employee classes because they are already imported from `jshell/snippets` with `try-with-jshell.sh`.

src/main/java/com/poiji/bind/Poiji.java

@@ -11,13 +11,13 @@
 
 import java.io.File;
 import java.io.InputStream;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.function.Consumer;
 
 import static com.poiji.util.PoijiConstants.XLSX_EXTENSION;
 import static com.poiji.util.PoijiConstants.XLS_EXTENSION;
-import java.util.ArrayList;
-import java.util.function.Consumer;
 
 /**
  * The entry point of the mapping process.
@@ -115,7 +115,7 @@ public static synchronized <T> List<T> fromExcel(final InputStream inputStream,
      * @param excelType type of the excel file, xls or xlsx
      * @param type type of the root object.
      * @param <T> type of the root object.
-     * @param consumer
+     * @param consumer represents an operation that accepts the type argument
      * @throws PoijiException if an internal exception occurs during the mapping process.
      * @throws InvalidExcelFileExtension if the specified excel file extension is invalid.
      * @throws IllegalCastException if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.
@@ -157,7 +157,7 @@ public static synchronized <T> List<T> fromExcel(final File file, final Class<T>
      * @param type type of the root object.
      * @param <T> type of the root object.
      * @param options specifies to change the default behaviour of the poiji.
-     * @param consumer output retrieves records
+     * @param consumer represents an operation that accepts the type argument
      * @throws PoijiException if an internal exception occurs during the mapping process.
      * @throws InvalidExcelFileExtension if the specified excel file extension is invalid.
      * @throws IllegalCastException if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.
@@ -200,7 +200,7 @@ public static synchronized <T> List<T> fromExcel(final InputStream inputStream,
      * @param type type of the root object.
      * @param <T> type of the root object.
      * @param options specifies to change the default behaviour of the poiji.
-     * @param consumer output retrieves records
+     * @param consumer represents an operation that accepts the type argument
      * @throws PoijiException if an internal exception occurs during the mapping process.
      * @throws InvalidExcelFileExtension if the specified excel file extension is invalid.
      * @throws IllegalCastException if this Field object is enforcing Java