implemented most of Field casting

README.md

@@ -131,6 +131,21 @@ System.out.println(isValid);
 Data values can be cast to native Java objects with a Field instance. This allows formats and constraints to be defined for the field in the [field descriptor](https://specs.frictionlessdata.io/table-schema/#field-descriptors):
 
 ```java
-// TODO: Casting has mostly been implemented in the TypeInferer class.
-// Need to hook up with Field class and document.
+Field intField = new Field("id", "integer");
+int intVal = intField.castValue("242");
+System.out.print(intVal);
+
+// 242
+
+Field datetimeField = new Field("date", "datetime");
+DateTime datetimeVal = datetimeField.castValue("2008-08-30T01:45:36.123Z");
+System.out.print(datetimeVal.getYear());
+
+// 2008
+
+Field geopointField = new Field("coordinates", "geopoint", "array");
+int[] geopointVal = geopointField.castValue("[12,21]");
+System.out.print("lon: " + geopointVal[0] + ", geopointVal: " + val[1]);
+
+// lon: 12, lat: 21
 ```

src/main/java/io/frictionlessdata/tableschema/Field.java

@@ -1,12 +1,16 @@
 package io.frictionlessdata.tableschema;
 
+import io.frictionlessdata.tableschema.exceptions.ConstraintsException;
+import io.frictionlessdata.tableschema.exceptions.InvalidCastException;
+import java.lang.reflect.Method;
 import org.json.JSONObject;
 
 /**
  *
  * 
  */
 public class Field {
+
     private String name = "";
     private String type = "";
     private String format = "default";
@@ -46,6 +50,36 @@ public Field(String name, String type, String format, String title, String descr
         this.constraints = constraints;
     }
 
+    /**
+     * Use the Field definition to cast a value into the Field type.
+     * @param <Any>
+     * @param value
+     * @return
+     * @throws InvalidCastException
+     * @throws ConstraintsException 
+     */
+    public <Any> Any castValue(String value) throws InvalidCastException, ConstraintsException{
+        if(this.type.isEmpty()){
+            throw new InvalidCastException();
+        }else{
+            try{
+                // Using reflection to invoke appropriate type casting method from the TypeInferrer class
+                String castMethodName = "cast" + (this.type.substring(0, 1).toUpperCase() + this.type.substring(1));
+                Method method = TypeInferrer.class.getMethod(castMethodName, String.class, String.class);
+                Object castValue = method.invoke(new TypeInferrer(), this.format, value);
+
+                return (Any)castValue;
+
+            }catch(Exception e){
+                throw new InvalidCastException();
+            }
+        } 
+    }
+
+    /**
+     * Get the JSON representation of the Field.
+     * @return 
+     */
     public JSONObject getJson(){
         JSONObject json = new JSONObject();
         json.put("name", this.name);
@@ -56,8 +90,5 @@ public JSONObject getJson(){
         json.put("constraints", this.constraints);
 
         return json;
-    }
-
-
-
+    }  
 }

src/main/java/io/frictionlessdata/tableschema/MainTest.java

@@ -6,6 +6,7 @@
 package io.frictionlessdata.tableschema;
 
 import java.net.URL;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
@@ -28,6 +29,7 @@ public static void main(String[] args) {
             URL url = new URL("https://raw.githubusercontent.com/frictionlessdata/tableschema-java/master/src/test/resources/fixtures/simple_data.csv");
             Table table = new Table(url);
 
+            /**
             // Iterate table
             Iterator<String[]> iter = table.iterator();
             while(iter.hasNext()){
@@ -52,7 +54,7 @@ public static void main(String[] args) {
             schema.addField(coordinatesField);
             
             System.out.println(schema.getJson());
-
+            **/
 
             // Build Schema with JSONObject instances
             /**
@@ -79,6 +81,7 @@ public static void main(String[] args) {
             System.out.println(schema2.getJson());
             **/
 
+            /**
             JSONObject schemaJsonObj3 = new JSONObject();
             Field nameField3 = new Field("id", "integer");
             schemaJsonObj3.put("fields", new JSONArray());
@@ -94,9 +97,27 @@ public static void main(String[] args) {
             
             isValid = schema3.validate();
             System.out.println(isValid);
+            **/
 
+            Field field = new Field("name", "geopoint", "default");
+            int[] val = field.castValue("12,21");
+            System.out.print("YPYOOY: " + val[0]);
+
+            /**
+            Field field2 = new Field("name", "geopoint", "array");
+            int[] val2 = field2.castValue("[12,21]");
+            System.out.print(val2[0]);
+            
+            Field field3 = new Field("name", "geopoint", "object");
+            int[] val3 = field3.castValue("{\"lon\": 12, \"lat\": 21}");
+            System.out.print(val[30]);
+   
+            Field field4 = new Field("name", "duration");
+            Duration val4 = field4.castValue("P2DT3H4M");
+            System.out.print(val4.getSeconds());
+            **/
 
-         
+
         }catch(Exception e){
             e.printStackTrace();
         }

src/main/java/io/frictionlessdata/tableschema/Table.java

@@ -1,5 +1,6 @@
 package io.frictionlessdata.tableschema;
 
+import io.frictionlessdata.tableschema.exceptions.TypeInferringException;
 import io.frictionlessdata.tableschema.datasources.CsvDataSource;
 import io.frictionlessdata.tableschema.datasources.DataSource;
 import org.json.*;

src/main/java/io/frictionlessdata/tableschema/TypeInferrer.java

@@ -1,5 +1,6 @@
 package io.frictionlessdata.tableschema;
 
+import io.frictionlessdata.tableschema.exceptions.TypeInferringException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -173,8 +174,10 @@ public JSONObject infer(List<String[]> data, String[] headers, int rowLimit) thr
 
     private void findType(String header, String datum){
 
+        // Invoke all the type casting methods using reflection.
         for(String[] typeInferralDefinition: TYPE_INFERRAL_ORDER_LIST){
             try{
+                // Keep invoking the type casting methods until one doesn't throw an exception
                 String dataType = typeInferralDefinition[0];
                 String castMethodName = "cast" + (dataType.substring(0, 1).toUpperCase() + dataType.substring(1));
                 String format = typeInferralDefinition[1];
@@ -238,8 +241,7 @@ public Duration castDuration(String format, String value) throws TypeInferringEx
             return Duration.parse(value); 
         }catch(Exception e){
             throw new TypeInferringException();
-        }    
-
+        }
     }
 
     /**

src/main/java/io/frictionlessdata/tableschema/exceptions/ConstraintsException.java

@@ -0,0 +1,30 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package io.frictionlessdata.tableschema.exceptions;
+
+/**
+ *
+ * @author pechorin
+ */
+public class ConstraintsException extends Exception {
+
+    /**
+     * Creates a new instance of <code>ConstraintsException</code> without
+     * detail message.
+     */
+    public ConstraintsException() {
+    }
+
+    /**
+     * Constructs an instance of <code>ConstraintsException</code> with the
+     * specified detail message.
+     *
+     * @param msg the detail message.
+     */
+    public ConstraintsException(String msg) {
+        super(msg);
+    }
+}

src/main/java/io/frictionlessdata/tableschema/exceptions/InvalidCastException.java

@@ -0,0 +1,30 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package io.frictionlessdata.tableschema.exceptions;
+
+/**
+ *
+ * @author pechorin
+ */
+public class InvalidCastException extends Exception {
+
+    /**
+     * Creates a new instance of <code>InvalidCastException</code> without
+     * detail message.
+     */
+    public InvalidCastException() {
+    }
+
+    /**
+     * Constructs an instance of <code>InvalidCastException</code> with the
+     * specified detail message.
+     *
+     * @param msg the detail message.
+     */
+    public InvalidCastException(String msg) {
+        super(msg);
+    }
+}

src/main/java/io/frictionlessdata/tableschema/TypeInferringException.java → src/main/java/io/frictionlessdata/tableschema/exceptions/TypeInferringException.java

@@ -3,7 +3,7 @@
  * To change this template file, choose Tools | Templates
  * and open the template in the editor.
  */
-package io.frictionlessdata.tableschema;
+package io.frictionlessdata.tableschema.exceptions;
 
 /**
  *