[ML][docs][minor] Define LabeledDocument/Document classes in CV example

To easier copy/paste Cross-Validation example code snippet need to define LabeledDocument/Document in it, since they difined in a previous example.

Author: Peter Rudenko <petro.rudenko@gmail.com>

Closes #5135 from petro-rudenko/patch-3 and squashes the following commits:

5190c75 [Peter Rudenko] Fix primitive types for java examples.
1d35383 [Peter Rudenko] [SQL][docs][minor] Define LabeledDocument/Document classes in CV example

docs/ml-guide.md

@@ -408,31 +408,31 @@ import org.apache.spark.sql.SQLContext;
 // Labeled and unlabeled instance types.
 // Spark SQL can infer schema from Java Beans.
 public class Document implements Serializable {
-  private Long id;
+  private long id;
   private String text;
 
-  public Document(Long id, String text) {
+  public Document(long id, String text) {
     this.id = id;
     this.text = text;
   }
 
-  public Long getId() { return this.id; }
-  public void setId(Long id) { this.id = id; }
+  public long getId() { return this.id; }
+  public void setId(long id) { this.id = id; }
 
   public String getText() { return this.text; }
   public void setText(String text) { this.text = text; }
 }
 
 public class LabeledDocument extends Document implements Serializable {
-  private Double label;
+  private double label;
 
-  public LabeledDocument(Long id, String text, Double label) {
+  public LabeledDocument(long id, String text, double label) {
     super(id, text);
     this.label = label;
   }
 
-  public Double getLabel() { return this.label; }
-  public void setLabel(Double label) { this.label = label; }
+  public double getLabel() { return this.label; }
+  public void setLabel(double label) { this.label = label; }
 }
 
 // Set up contexts.
@@ -565,6 +565,11 @@ import org.apache.spark.ml.tuning.{ParamGridBuilder, CrossValidator}
 import org.apache.spark.mllib.linalg.Vector
 import org.apache.spark.sql.{Row, SQLContext}
 
+// Labeled and unlabeled instance types.
+// Spark SQL can infer schema from case classes.
+case class LabeledDocument(id: Long, text: String, label: Double)
+case class Document(id: Long, text: String)
+
 val conf = new SparkConf().setAppName("CrossValidatorExample")
 val sc = new SparkContext(conf)
 val sqlContext = new SQLContext(sc)
@@ -655,6 +660,36 @@ import org.apache.spark.sql.DataFrame;
 import org.apache.spark.sql.Row;
 import org.apache.spark.sql.SQLContext;
 
+// Labeled and unlabeled instance types.
+// Spark SQL can infer schema from Java Beans.
+public class Document implements Serializable {
+  private long id;
+  private String text;
+
+  public Document(long id, String text) {
+    this.id = id;
+    this.text = text;
+  }
+
+  public long getId() { return this.id; }
+  public void setId(long id) { this.id = id; }
+
+  public String getText() { return this.text; }
+  public void setText(String text) { this.text = text; }
+}
+
+public class LabeledDocument extends Document implements Serializable {
+  private double label;
+
+  public LabeledDocument(long id, String text, double label) {
+    super(id, text);
+    this.label = label;
+  }
+
+  public double getLabel() { return this.label; }
+  public void setLabel(double label) { this.label = label; }
+}
+
 SparkConf conf = new SparkConf().setAppName("JavaCrossValidatorExample");
 JavaSparkContext jsc = new JavaSparkContext(conf);
 SQLContext jsql = new SQLContext(jsc);