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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.lob;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;
import com.amazon.carbonado.FetchException;
import com.amazon.carbonado.PersistException;
/**
* A Clob implementation which is backed by a Blob. Data is stored in the Blob
* using UTF-16BE encoding.
*
* @author Brian S O'Neill
* @author Bob Loblaw
*/
public class BlobClob extends AbstractClob {
private static final Charset UTF_16BE = Charset.forName("UTF-16BE");
private final Blob mBlob;
/**
* @param blob blob to wrap
*/
public BlobClob(Blob blob) {
mBlob = blob;
}
public Reader openReader() throws FetchException {
return new BufferedReader(new InputStreamReader(mBlob.openInputStream(), UTF_16BE));
}
public Reader openReader(long pos) throws FetchException {
return openReader(pos, -1);
}
public Reader openReader(long pos, int bufferSize) throws FetchException {
rangeCheck(pos, "Position");
Reader reader = new InputStreamReader(mBlob.openInputStream(pos << 1, 0), UTF_16BE);
if (bufferSize < 0) {
reader = new BufferedReader(reader);
} else if (bufferSize > 0) {
reader = new BufferedReader(reader, bufferSize);
}
return reader;
}
public long getLength() throws FetchException {
return mBlob.getLength() >> 1;
}
public Writer openWriter() throws PersistException {
return new BufferedWriter(new OutputStreamWriter(mBlob.openOutputStream(), UTF_16BE));
}
public Writer openWriter(long pos) throws PersistException {
return openWriter(pos, -1);
}
public Writer openWriter(long pos, int bufferSize) throws PersistException {
rangeCheck(pos, "Position");
Writer writer = new OutputStreamWriter(mBlob.openOutputStream(pos << 1, 0), UTF_16BE);
if (bufferSize < 0) {
writer = new BufferedWriter(writer);
} else if (bufferSize > 0) {
writer = new BufferedWriter(writer, bufferSize);
}
return writer;
}
public void setLength(long length) throws PersistException {
rangeCheck(length, "Length");
mBlob.setLength(length << 1);
}
public Object getLocator() {
return mBlob.getLocator();
}
protected Blob getWrappedBlob() {
return mBlob;
}
private void rangeCheck(long value, String type) {
if (value < 0) {
throw new IllegalArgumentException(type + " is negative: " + value);
}
if (value > (Long.MAX_VALUE >> 1)) {
throw new IllegalArgumentException(type + " too large: " + value);
}
}
}
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