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IN PROGRESS - BATCH-712: Upgrade ItemReaders to use Parameterized types

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the problematic AggregateItemReader - used wildcards (not to give false promises to clients)
This commit is contained in:
robokaso
2008-07-21 12:51:29 +00:00
parent b39ba55bcc
commit 05f94e5a15
1 changed files with 32 additions and 14 deletions
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46
spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/AggregateItemReader.java
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@@ -17,19 +17,22 @@
package org.springframework.batch.item.support;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.MarkFailedException;
import org.springframework.batch.item.ResetFailedException;
import org.springframework.batch.item.file.mapping.FieldSetMapper;
/**
* An {@link ItemReader} that delivers a list as its item, storing up objects
* from the injected {@link ItemReader} until they are ready to be packed out
* as a collection. The {@link ItemReader} should mark the beginning and end of
* records with the constant values in {@link FieldSetMapper} ({@link AggregateItemReader#BEGIN_RECORD}
* and {@link AggregateItemReader#END_RECORD}).<br/>
* from the injected {@link ItemReader} until they are ready to be packed out as
* a collection. The {@link ItemReader} should mark the beginning and end of
* records with the constant values in {@link FieldSetMapper} (
* {@link AggregateItemReader#BEGIN_RECORD} and
* {@link AggregateItemReader#END_RECORD}).<br/>
*
* This class is thread safe (it can be used concurrently by multiple threads)
* as long as the {@link ItemReader} is also thread safe.
@@ -37,10 +40,9 @@ import org.springframework.batch.item.file.mapping.FieldSetMapper;
* @author Dave Syer
*
*/
public class AggregateItemReader extends DelegatingItemReader {
public class AggregateItemReader implements ItemReader<List<?>> {
private static final Log log = LogFactory
.getLog(AggregateItemReader.class);
private static final Log log = LogFactory.getLog(AggregateItemReader.class);
/**
* Marker for the end of a multi-object record.
@@ -52,22 +54,25 @@ public class AggregateItemReader extends DelegatingItemReader {
*/
public static final Object BEGIN_RECORD = new Object();
private ItemReader<?> itemReader;
/**
* Get the next list of records.
* @throws Exception
* @throws Exception
*
* @see org.springframework.batch.item.ItemReader#read()
*/
public Object read() throws Exception {
public List<?> read() throws Exception {
ResultHolder holder = new ResultHolder();
while (process(super.read(), holder)) {
while (process(itemReader.read(), holder)) {
continue;
}
if (!holder.exhausted) {
return holder.records;
} else {
}
else {
return null;
}
}
@@ -98,6 +103,18 @@ public class AggregateItemReader extends DelegatingItemReader {
return true;
}
public void mark() throws MarkFailedException {
itemReader.mark();
}
public void reset() throws ResetFailedException {
itemReader.reset();
}
public void setItemReader(ItemReader<?> itemReader) {
this.itemReader = itemReader;
}
/**
* Private class for temporary state management while item is being
* collected.
@@ -105,8 +122,9 @@ public class AggregateItemReader extends DelegatingItemReader {
* @author Dave Syer
*
*/
private static class ResultHolder {
Collection<Object> records = new ArrayList<Object>();
private class ResultHolder {
List<Object> records = new ArrayList<Object>();
boolean exhausted = false;
}