OPEN - issue BATCH-767: Update documentation for M2

http://jira.springframework.org/browse/BATCH-767

First pass through chapters 2, 3 and Appendix A.

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ItemReader.java

@@ -46,6 +46,6 @@ public interface ItemReader<T> {
 	 * 
 	 * @throws Exception if an underlying resource is unavailable.
 	 */
-	T read() throws Exception, UnexpectedInputException, NoWorkFoundException, ParseException;
+	T read() throws Exception, UnexpectedInputException, ParseException;
 
 }

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/database/JpaPagingItemReader.java

@@ -43,7 +43,7 @@ import org.springframework.util.ClassUtils;
  * better performance.
  *
  * In order to reduce the memory usage for large results the persistence context is flushed and cleared
- * after each page is read.  This cuases any entities read to be detached. If you make changes to the
+ * after each page is read.  This causes any entities read to be detached. If you make changes to the
  * entities and want the changes persisted then you must explicitly merge the entities.
  *
  * The reader must be configured with an {@link javax.persistence.EntityManagerFactory}.  All entity access

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/mapping/LineMapper.java

@@ -1,13 +1,33 @@
 package org.springframework.batch.item.file.mapping;
 
+import org.springframework.batch.item.file.FlatFileItemReader;
+import org.springframework.batch.item.file.transform.LineTokenizer;
+
+
 /**
- * Interface for mapping lines (strings) to domain objects.
+ * Interface for mapping lines (strings) to domain objects typically used by
+ * {@link FlatFileItemReader} to map lines read from a file to domain objects
+ * on a per line basis.  Implementations of this interface perform the actual
+ * work of parsing a line without having to deal with how the line was
+ * obtained.  
  * 
  * @author Robert Kasanicky
- *
  * @param <T> type of the domain object
+ * @see FieldSetMapper
+ * @see LineTokenizer
+ * @since 2.0
  */
 public interface LineMapper<T> {
 
+	/**
+	 * Implementations must implement this method to map the provided line to 
+	 * the parameter type T.  The line number represents the number of lines
+	 * into a file the current line resides.
+	 * 
+	 * @param line to be mapped
+	 * @param lineNumber of the current line
+	 * @return mapped object of type T
+	 * @throws Exception if error occured while parsing.
+	 */
 	T mapLine(String line, int lineNumber) throws Exception;
 }

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/AbstractItemCountingItemStreamItemReader.java

@@ -4,7 +4,6 @@ import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemStream;
 import org.springframework.batch.item.ItemStreamException;
-import org.springframework.batch.item.NoWorkFoundException;
 import org.springframework.batch.item.ParseException;
 import org.springframework.batch.item.UnexpectedInputException;
 import org.springframework.batch.item.util.ExecutionContextUserSupport;
@@ -57,7 +56,7 @@ public abstract class AbstractItemCountingItemStreamItemReader<T> implements Ite
 		}
 	}
 
-	public T read() throws Exception, UnexpectedInputException, NoWorkFoundException, ParseException {
+	public T read() throws Exception, UnexpectedInputException, ParseException {
 		currentItemCount++;
 		return doRead();
 	}