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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. All rights reserved.
* Modifications Copyright (C) 2020-2021 Nordix Foundation.
* ================================================================================
* 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.service.engine.event.impl.filecarrierplugin.consumer;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Queue;
import java.util.concurrent.LinkedBlockingQueue;
import org.onap.policy.apex.core.infrastructure.threading.ApplicationThreadFactory;
import org.onap.policy.apex.core.infrastructure.threading.ThreadUtilities;
import org.onap.policy.apex.service.parameters.eventprotocol.EventProtocolTextTokenDelimitedParameters;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;
/**
* The Class TextBlockReader reads the next block of text from an input stream.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
public class HeaderDelimitedTextBlockReader implements TextBlockReader, Runnable {
// The logger for this class
private static final XLogger LOGGER = XLoggerFactory.getXLogger(HeaderDelimitedTextBlockReader.class);
// The amount of time to wait for input on the text block reader
private static final long TEXT_BLOCK_DELAY = 250;
// Tag for the start and end of text blocks
private final String blockStartToken;
private final String blockEndToken;
// Indicates that text block processing starts at the first block of text
private final boolean delimiterAtStart;
private boolean blockEndTokenUsed;
// The thread used to read the text from the stream
private Thread textConsumputionThread;
// The input stream for text
private InputStream inputStream;
// The lines of input read from the input stream
private final Queue<String> textLineQueue = new LinkedBlockingQueue<>();
// True while EOF has not been seen on input
private boolean eofOnInputStream = false;
/**
* Constructor, initialize the text block reader using token delimited event protocol parameters.
*
* @param tokenDelimitedParameters
* the token delimited event protocol parameters
*/
public HeaderDelimitedTextBlockReader(final EventProtocolTextTokenDelimitedParameters tokenDelimitedParameters) {
this(tokenDelimitedParameters.getStartDelimiterToken(), tokenDelimitedParameters.getEndDelimiterToken(),
tokenDelimitedParameters.isDelimiterAtStart());
}
/**
* Constructor, initialize the text block reader.
*
* @param blockStartToken
* the block start token for the start of a text block
* @param blockEndToken
* the block end token for the end of a text block
* @param delimiterAtStart
* indicates that text block processing starts at the first block of text
*/
public HeaderDelimitedTextBlockReader(final String blockStartToken, final String blockEndToken,
final boolean delimiterAtStart) {
this.blockStartToken = blockStartToken;
this.delimiterAtStart = delimiterAtStart;
if (blockEndToken == null) {
this.blockEndToken = blockStartToken;
this.blockEndTokenUsed = false;
} else {
this.blockEndToken = blockEndToken;
this.blockEndTokenUsed = true;
}
}
/**
* {@inheritDoc}.
*/
@Override
public void init(final InputStream incomingInputStream) {
this.inputStream = incomingInputStream;
// Configure and start the text reading thread
textConsumputionThread = new ApplicationThreadFactory(this.getClass().getName()).newThread(this);
textConsumputionThread.setDaemon(true);
textConsumputionThread.start();
}
/**
* {@inheritDoc}.
*/
@Override
public TextBlock readTextBlock() throws IOException {
// Holder for the current text block
final StringBuilder textBlockBuilder = new StringBuilder();
// Wait for the timeout period if there is no input
if (!eofOnInputStream && textLineQueue.isEmpty()) {
ThreadUtilities.sleep(TEXT_BLOCK_DELAY);
}
// Scan the lines in the queue
while (!textLineQueue.isEmpty()) {
// Scroll down in the available lines looking for the start of the text block
if (!delimiterAtStart || textLineQueue.peek().startsWith(blockStartToken)) {
// Process the input line header
textBlockBuilder.append(textLineQueue.remove());
textBlockBuilder.append('\n');
break;
} else {
String consumer = textLineQueue.remove();
LOGGER.warn("invalid input on consumer: {}", consumer);
}
}
// Get the rest of the text document
while (!textLineQueue.isEmpty() && !textLineQueue.peek().startsWith(blockEndToken)
&& !textLineQueue.peek().startsWith(blockStartToken)) {
// We just strip out block end tokens because we use block start tokens to delimit the blocks of text
textBlockBuilder.append(textLineQueue.remove());
textBlockBuilder.append('\n');
}
// Check if we should add the block end token to the end of the text block
if (!textLineQueue.isEmpty() && blockEndTokenUsed && textLineQueue.peek().startsWith(blockEndToken)) {
// Process the input line header
textBlockBuilder.append(textLineQueue.remove());
textBlockBuilder.append('\n');
}
// Condition the text block and return it
final String textBlock = textBlockBuilder.toString().trim();
final boolean endOfText = eofOnInputStream && textLineQueue.isEmpty();
if (textBlock.length() > 0) {
return new TextBlock(endOfText, textBlock);
} else {
return new TextBlock(endOfText, null);
}
}
/**
* {@inheritDoc}.
*/
@Override
public void run() {
try (BufferedReader textReader = new BufferedReader(new InputStreamReader(inputStream))) {
// Read the input line by line until we see end of file on the stream
String line;
while ((line = textReader.readLine()) != null) {
textLineQueue.add(line);
}
} catch (final IOException e) {
LOGGER.warn("I/O exception on text input on consumer: ", e);
} finally {
eofOnInputStream = true;
}
}
}
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