org.springframework.core.codec.CharSequenceEncoder Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* 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
*
* https://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.springframework.core.codec;
import java.nio.charset.Charset;
import java.nio.charset.CoderMalfunctionError;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import org.springframework.core.ResolvableType;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.log.LogFormatUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.MimeType;
import org.springframework.util.MimeTypeUtils;
/**
* Encode from a {@code CharSequence} stream to a bytes stream.
*
* @author Sebastien Deleuze
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @since 5.0
* @see StringDecoder
*/
public final class CharSequenceEncoder extends AbstractEncoder {
/**
* The default charset used by the encoder.
*/
public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
private final ConcurrentMap charsetToMaxBytesPerChar =
new ConcurrentHashMap<>(3);
private CharSequenceEncoder(MimeType... mimeTypes) {
super(mimeTypes);
}
@Override
public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType) {
Class clazz = elementType.toClass();
return super.canEncode(elementType, mimeType) && CharSequence.class.isAssignableFrom(clazz);
}
@Override
public Flux encode(Publisher inputStream,
DataBufferFactory bufferFactory, ResolvableType elementType,
@Nullable MimeType mimeType, @Nullable Map hints) {
Charset charset = getCharset(mimeType);
return Flux.from(inputStream).map(charSequence -> {
if (!Hints.isLoggingSuppressed(hints)) {
LogFormatUtils.traceDebug(logger, traceOn -> {
String formatted = LogFormatUtils.formatValue(charSequence, !traceOn);
return Hints.getLogPrefix(hints) + "Writing " + formatted;
});
}
boolean release = true;
int capacity = calculateCapacity(charSequence, charset);
DataBuffer dataBuffer = bufferFactory.allocateBuffer(capacity);
try {
dataBuffer.write(charSequence, charset);
release = false;
}
catch (CoderMalfunctionError ex) {
throw new EncodingException("String encoding error: " + ex.getMessage(), ex);
}
finally {
if (release) {
DataBufferUtils.release(dataBuffer);
}
}
return dataBuffer;
});
}
int calculateCapacity(CharSequence sequence, Charset charset) {
float maxBytesPerChar = this.charsetToMaxBytesPerChar
.computeIfAbsent(charset, cs -> cs.newEncoder().maxBytesPerChar());
float maxBytesForSequence = sequence.length() * maxBytesPerChar;
return (int) Math.ceil(maxBytesForSequence);
}
private Charset getCharset(@Nullable MimeType mimeType) {
if (mimeType != null && mimeType.getCharset() != null) {
return mimeType.getCharset();
}
else {
return DEFAULT_CHARSET;
}
}
/**
* Create a {@code CharSequenceEncoder} that supports only "text/plain".
*/
public static CharSequenceEncoder textPlainOnly() {
return new CharSequenceEncoder(new MimeType("text", "plain", DEFAULT_CHARSET));
}
/**
* Create a {@code CharSequenceEncoder} that supports all MIME types.
*/
public static CharSequenceEncoder allMimeTypes() {
return new CharSequenceEncoder(new MimeType("text", "plain", DEFAULT_CHARSET), MimeTypeUtils.ALL);
}
}