/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.nifi.controller.repository.claim;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import org.apache.nifi.controller.repository.ContentRepository;
public class ContentClaimWriteCache {
private final ContentRepository contentRepo;
private final Map<ResourceClaim, OutputStream> streamMap = new HashMap<>();
private final Queue<ContentClaim> queue = new LinkedList<>();
private final int bufferSize;
public ContentClaimWriteCache(final ContentRepository contentRepo) {
this(contentRepo, 8192);
}
public ContentClaimWriteCache(final ContentRepository contentRepo, final int bufferSize) {
this.contentRepo = contentRepo;
this.bufferSize = bufferSize;
}
public void reset() throws IOException {
try {
forEachStream(OutputStream::close);
} finally {
streamMap.clear();
queue.clear();
}
}
public ContentClaim getContentClaim() throws IOException {
final ContentClaim contentClaim = queue.poll();
if (contentClaim != null) {
contentRepo.incrementClaimaintCount(contentClaim);
return contentClaim;
}
final ContentClaim claim = contentRepo.create(false);
registerStream(claim);
return claim;
}
private OutputStream registerStream(final ContentClaim contentClaim) throws IOException {
final OutputStream out = contentRepo.write(contentClaim);
final OutputStream buffered = new BufferedOutputStream(out, bufferSize);
streamMap.put(contentClaim.getResourceClaim(), buffered);
return buffered;
}
public OutputStream write(final ContentClaim claim) throws IOException {
OutputStream out = streamMap.get(claim.getResourceClaim());
if (out == null) {
out = registerStream(claim);
}
if (!(claim instanceof StandardContentClaim)) {
// we know that we will only create Content Claims that are of type StandardContentClaim, so if we get anything
// else, just throw an Exception because it is not valid for this Repository
throw new IllegalArgumentException("Cannot write to " + claim + " because that Content Claim does belong to this Claim Cache");
}
final StandardContentClaim scc = (StandardContentClaim) claim;
final long initialLength = Math.max(0L, scc.getLength());
final OutputStream bcos = out;
return new OutputStream() {
private long bytesWritten = 0L;
@Override
public void write(final int b) throws IOException {
bcos.write(b);
bytesWritten++;
scc.setLength(initialLength + bytesWritten);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
bcos.write(b, off, len);
bytesWritten += len;
scc.setLength(initialLength + bytesWritten);
}
@Override
public void write(final byte[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void flush() throws IOException {
// do nothing - do not flush underlying stream.
}
@Override
public void close() throws IOException {
queue.offer(claim);
}
};
}
public void flush(final ContentClaim contentClaim) throws IOException {
if (contentClaim == null) {
return;
}
flush(contentClaim.getResourceClaim());
}
public void flush(final ResourceClaim claim) throws IOException {
final OutputStream out = streamMap.get(claim);
if (out != null) {
out.flush();
}
}
public void flush() throws IOException {
forEachStream(OutputStream::flush);
}
private void forEachStream(final StreamProcessor proc) throws IOException {
IOException exception = null;
for (final OutputStream out : streamMap.values()) {
try {
proc.process(out);
} catch (final IOException ioe) {
if (exception == null) {
exception = ioe;
} else {
ioe.addSuppressed(exception);
exception = ioe;
}
}
}
if (exception != null) {
throw exception;
}
}
private interface StreamProcessor {
void process(final OutputStream out) throws IOException;
}
}