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/*
* Copyright 2006 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.qe;
import java.io.IOException;
import java.lang.reflect.UndeclaredThrowableException;
import com.amazon.carbonado.Cursor;
import com.amazon.carbonado.FetchException;
import com.amazon.carbonado.FetchMultipleException;
import com.amazon.carbonado.FetchNoneException;
import com.amazon.carbonado.PersistException;
import com.amazon.carbonado.PersistNoneException;
import com.amazon.carbonado.Query;
import com.amazon.carbonado.Storable;
import com.amazon.carbonado.filter.Filter;
import com.amazon.carbonado.util.Appender;
/**
* AbstractQuery implements a small set of common Query methods. Subclasses
* should consider overriding some of these methods, if it provides better
* performance.
*
* @author Brian S O'Neill
*/
public abstract class AbstractQuery<S extends Storable> implements Query<S>, Appender {
protected AbstractQuery() {
}
public Query<S> and(String filter) throws FetchException {
return and(Filter.filterFor(getStorableType(), filter));
}
public Query<S> or(String filter) throws FetchException {
return or(Filter.filterFor(getStorableType(), filter));
}
public S loadOne() throws FetchException {
S obj = tryLoadOne();
if (obj == null) {
throw new FetchNoneException(toString());
}
return obj;
}
public S tryLoadOne() throws FetchException {
Cursor<S> cursor = fetch();
try {
if (cursor.hasNext()) {
S obj = cursor.next();
if (cursor.hasNext()) {
throw new FetchMultipleException(toString());
}
return obj;
} else {
return null;
}
} finally {
cursor.close();
}
}
public void deleteOne() throws PersistException {
if (!tryDeleteOne()) {
throw new PersistNoneException(toString());
}
}
public boolean printNative() {
try {
return printNative(System.out);
} catch (IOException e) {
// Shouldn't happen since PrintStream suppresses exceptions.
throw new UndeclaredThrowableException(e);
}
}
public boolean printNative(Appendable app) throws IOException {
return printNative(app, 0);
}
public boolean printPlan() {
try {
return printPlan(System.out);
} catch (IOException e) {
// Shouldn't happen since PrintStream suppresses exceptions.
throw new UndeclaredThrowableException(e);
}
}
public boolean printPlan(Appendable app) throws IOException {
return printPlan(app, 0);
}
/**
* Implementation calls appendTo.
*/
@Override
public String toString() {
StringBuilder b = new StringBuilder();
try {
appendTo(b);
} catch (IOException e) {
// Not gonna happen
}
return b.toString();
}
}
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