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/*
* Copyright 2006-2012 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.amazon.carbonado.cursor;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.NoSuchElementException;
import com.amazon.carbonado.Cursor;
import com.amazon.carbonado.FetchException;
/**
* AbstractCursor implements a small set of common Cursor methods.
*
* @author Brian S O'Neill
*/
public abstract class AbstractCursor<S> implements Cursor<S> {
// Note: Since constructor takes no parameters, this class is called
// Abstract instead of Base.
protected AbstractCursor() {
}
public int copyInto(Collection<? super S> c) throws FetchException {
try {
int count = 0;
try {
while (hasNext()) {
c.add(next());
count++;
}
} catch (NoSuchElementException e) {
// Race condition cause by concurrent repository close.
silentClose();
}
return count;
} catch (FetchException e) {
silentClose();
throw e;
}
}
public int copyInto(Collection<? super S> c, int limit) throws FetchException {
try {
int count = 0;
try {
while (--limit >= 0 && hasNext()) {
c.add(next());
count++;
}
} catch (NoSuchElementException e) {
// Race condition cause by concurrent repository close.
silentClose();
}
return count;
} catch (FetchException e) {
silentClose();
throw e;
}
}
public List<S> toList() throws FetchException {
try {
List<S> list = new ArrayList<S>();
copyInto(list);
return list;
} catch (FetchException e) {
silentClose();
throw e;
}
}
public List<S> toList(int limit) throws FetchException {
try {
List<S> list = new ArrayList<S>();
copyInto(list, limit);
return list;
} catch (FetchException e) {
silentClose();
throw e;
}
}
public int skipNext(int amount) throws FetchException {
if (amount <= 0) {
if (amount < 0) {
throw new IllegalArgumentException("Cannot skip negative amount: " + amount);
}
return 0;
}
try {
int count = 0;
try {
while (--amount >= 0 && hasNext()) {
next();
count++;
}
} catch (NoSuchElementException e) {
// Race condition cause by concurrent repository close.
silentClose();
}
return count;
} catch (FetchException e) {
silentClose();
throw e;
}
}
private void silentClose() {
try {
close();
} catch (Exception e2) {
// Don't care.
}
}
}
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