com.groupbyinc.common.jackson.dataformat.yaml.YAMLGenerator Maven / Gradle / Ivy
package com.fasterxml.jackson.dataformat.yaml;
import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.regex.Pattern;
import org.yaml.snakeyaml.DumperOptions;
import org.yaml.snakeyaml.DumperOptions.FlowStyle;
import org.yaml.snakeyaml.emitter.Emitter;
import org.yaml.snakeyaml.events.*;
import org.yaml.snakeyaml.nodes.Tag;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.base.GeneratorBase;
import com.fasterxml.jackson.core.json.JsonWriteContext;
import com.fasterxml.jackson.core.io.IOContext;
public class YAMLGenerator extends GeneratorBase
{
/**
* Enumeration that defines all togglable features for YAML generators
*/
public enum Feature implements FormatFeature // since 2.9
{
/**
* Whether we are to write an explicit document start marker ("---")
* or not.
*
* @since 2.3
*/
WRITE_DOC_START_MARKER(true),
/**
* Whether to use YAML native Object Id construct for indicating type (true);
* or "generic" Object Id mechanism (false). Former works better for systems that
* are YAML-centric; latter may be better choice for interoperability, when
* converting between formats or accepting other formats.
*
* @since 2.5
*/
USE_NATIVE_OBJECT_ID(true),
/**
* Whether to use YAML native Type Id construct for indicating type (true);
* or "generic" type property (false). Former works better for systems that
* are YAML-centric; latter may be better choice for interoperability, when
* converting between formats or accepting other formats.
*
* @since 2.5
*/
USE_NATIVE_TYPE_ID(true),
/**
* Do we try to force so-called canonical output or not.
*/
CANONICAL_OUTPUT(false),
/**
* Options passed to SnakeYAML that determines whether longer textual content
* gets automatically split into multiple lines or not.
*
* Feature is enabled by default to conform to SnakeYAML defaults as well as
* backwards compatibility with 2.5 and earlier versions.
*
* @since 2.6
*/
SPLIT_LINES(true),
/**
* Whether strings will be rendered without quotes (true) or
* with quotes (false, default).
*
* Minimized quote usage makes for more human readable output; however, content is
* limited to printable characters according to the rules of
* literal block style.
*
* @since 2.7
*/
MINIMIZE_QUOTES(false),
/**
* Whether numbers stored as strings will be rendered with quotes (true) or
* without quotes (false, default) when MINIMIZE_QUOTES is enabled.
*
* Minimized quote usage makes for more human readable output; however, content is
* limited to printable characters according to the rules of
* literal block style.
*
* @since 2.8.2
*/
ALWAYS_QUOTE_NUMBERS_AS_STRINGS(false),
/**
* Whether for string containing newlines a literal block style
* should be used. This automatically enabled when {@link #MINIMIZE_QUOTES} is set.
*
* The content of such strings is limited to printable characters according to the rules of
* literal block style.
*
* @since 2.9
*/
LITERAL_BLOCK_STYLE(false),
/**
* Feature enabling of which adds indentation for array entry generation
* (default indentation being 2 spaces).
*
* Default value is `false` for backwards compatibility
*
* @since 2.9
*/
INDENT_ARRAYS(false),
/**
* Option passed to SnakeYAML that determines if the line breaks used for
* serialization should be same as what the default is for current platform.
* If disabled, Unix linefeed ({@code \n}) will be used.
*
* Default value is `false` for backwards compatibility.
*
* @since 2.9.6
*/
USE_PLATFORM_LINE_BREAKS(false),
;
protected final boolean _defaultState;
protected final int _mask;
/**
* Method that calculates bit set (flags) of all features that
* are enabled by default.
*/
public static int collectDefaults()
{
int flags = 0;
for (Feature f : values()) {
if (f.enabledByDefault()) {
flags |= f.getMask();
}
}
return flags;
}
private Feature(boolean defaultState) {
_defaultState = defaultState;
_mask = (1 << ordinal());
}
@Override
public boolean enabledByDefault() { return _defaultState; }
@Override
public boolean enabledIn(int flags) { return (flags & _mask) != 0; }
@Override
public int getMask() { return _mask; }
}
/*
/**********************************************************
/* Internal constants
/**********************************************************
*/
protected final static long MIN_INT_AS_LONG = (long) Integer.MIN_VALUE;
protected final static long MAX_INT_AS_LONG = (long) Integer.MAX_VALUE;
protected final static Pattern PLAIN_NUMBER_P = Pattern.compile("[0-9]*(\\.[0-9]*)?");
protected final static String TAG_BINARY = Tag.BINARY.toString();
/*
/**********************************************************
/* Configuration
/**********************************************************
*/
final protected IOContext _ioContext;
/**
* Bit flag composed of bits that indicate which
* {@link YAMLGenerator.Feature}s
* are enabled.
*/
protected int _formatFeatures;
protected Writer _writer;
protected DumperOptions _outputOptions;
// for field names, leave out quotes
private final static Character STYLE_NAME = null;
// numbers, booleans, should use implicit
private final static Character STYLE_SCALAR = null;
// Strings quoted for fun
private final static Character STYLE_QUOTED = Character.valueOf('"');
// Strings in literal (block) style
private final static Character STYLE_LITERAL = Character.valueOf('|');
// Which flow style to use for Base64? Maybe basic quoted?
// 29-Nov-2017, tatu: Actually SnakeYAML uses block style so:
private final static Character STYLE_BASE64 = STYLE_LITERAL;
private final static Character STYLE_PLAIN = null;
/*
/**********************************************************
/* Output state
/**********************************************************
*/
protected Emitter _emitter;
/**
* YAML supports native Object identifiers, so databinder may indicate
* need to output one.
*/
protected String _objectId;
/**
* YAML supports native Type identifiers, so databinder may indicate
* need to output one.
*/
protected String _typeId;
/*
/**********************************************************
/* Life-cycle
/**********************************************************
*/
public YAMLGenerator(IOContext ctxt, int jsonFeatures, int yamlFeatures,
ObjectCodec codec, Writer out,
org.yaml.snakeyaml.DumperOptions.Version version)
throws IOException
{
super(jsonFeatures, codec);
_ioContext = ctxt;
_formatFeatures = yamlFeatures;
_writer = out;
_outputOptions = buildDumperOptions(jsonFeatures, yamlFeatures, version);
_emitter = new Emitter(_writer, _outputOptions);
// should we start output now, or try to defer?
_emitter.emit(new StreamStartEvent(null, null));
Map noTags = Collections.emptyMap();
boolean startMarker = Feature.WRITE_DOC_START_MARKER.enabledIn(yamlFeatures);
_emitter.emit(new DocumentStartEvent(null, null, startMarker,
version, // for 1.10 was: ((version == null) ? null : version.getArray()),
noTags));
}
protected DumperOptions buildDumperOptions(int jsonFeatures, int yamlFeatures,
org.yaml.snakeyaml.DumperOptions.Version version)
{
DumperOptions opt = new DumperOptions();
// would we want canonical?
if (Feature.CANONICAL_OUTPUT.enabledIn(_formatFeatures)) {
opt.setCanonical(true);
} else {
opt.setCanonical(false);
// if not, MUST specify flow styles
opt.setDefaultFlowStyle(FlowStyle.BLOCK);
}
// split-lines for text blocks?
opt.setSplitLines(Feature.SPLIT_LINES.enabledIn(_formatFeatures));
// array indentation?
if (Feature.INDENT_ARRAYS.enabledIn(_formatFeatures)) {
// But, wrt [dataformats-text#34]: need to set both to diff values to work around bug
// (otherwise indentation level is "invisible". Note that this should NOT be necessary
// but is needed up to at least SnakeYAML 1.18.
// Also looks like all kinds of values do work, except for both being 2... weird.
opt.setIndicatorIndent(1);
opt.setIndent(2);
}
// 14-May-2018: [dataformats-text#84] allow use of platform linefeed
if (Feature.USE_PLATFORM_LINE_BREAKS.enabledIn(_formatFeatures)) {
opt.setLineBreak(DumperOptions.LineBreak.getPlatformLineBreak());
}
return opt;
}
/*
/**********************************************************
/* Versioned
/**********************************************************
*/
@Override
public Version version() {
return PackageVersion.VERSION;
}
/*
/**********************************************************
/* Overridden methods, configuration
/**********************************************************
*/
/**
* Not sure what to do here; could reset indentation to some value maybe?
*/
@Override
public YAMLGenerator useDefaultPrettyPrinter()
{
return this;
}
/**
* Not sure what to do here; will always indent, but uses
* YAML-specific settings etc.
*/
@Override
public YAMLGenerator setPrettyPrinter(PrettyPrinter pp) {
return this;
}
@Override
public Object getOutputTarget() {
return _writer;
}
/**
* SnakeYAML does not expose buffered content amount, so we can only return
* -1 from here
*/
@Override
public int getOutputBuffered() {
return -1;
}
@Override
public int getFormatFeatures() {
return _formatFeatures;
}
@Override
public JsonGenerator overrideFormatFeatures(int values, int mask) {
// 14-Mar-2016, tatu: Should re-configure, but unfortunately most
// settings passed via options passed to constructor of Emitter
_formatFeatures = (_formatFeatures & ~mask) | (values & mask);
return this;
}
@Override
public boolean canUseSchema(FormatSchema schema) {
return false;
}
@Override
public boolean canWriteFormattedNumbers() { return true; }
//@Override public void setSchema(FormatSchema schema)
/*
/**********************************************************
/* Extended API, configuration
/**********************************************************
*/
public YAMLGenerator enable(Feature f) {
_formatFeatures |= f.getMask();
return this;
}
public YAMLGenerator disable(Feature f) {
_formatFeatures &= ~f.getMask();
return this;
}
public final boolean isEnabled(Feature f) {
return (_formatFeatures & f.getMask()) != 0;
}
public YAMLGenerator configure(Feature f, boolean state) {
if (state) {
enable(f);
} else {
disable(f);
}
return this;
}
/*
/**********************************************************************
/* Overridden methods; writing field names
/**********************************************************************
*/
/* And then methods overridden to make final, streamline some
* aspects...
*/
@Override
public final void writeFieldName(String name) throws IOException
{
if (_writeContext.writeFieldName(name) == JsonWriteContext.STATUS_EXPECT_VALUE) {
_reportError("Can not write a field name, expecting a value");
}
_writeFieldName(name);
}
@Override
public final void writeFieldName(SerializableString name)
throws IOException
{
// Object is a value, need to verify it's allowed
if (_writeContext.writeFieldName(name.getValue()) == JsonWriteContext.STATUS_EXPECT_VALUE) {
_reportError("Can not write a field name, expecting a value");
}
_writeFieldName(name.getValue());
}
@Override
public final void writeStringField(String fieldName, String value)
throws IOException
{
if (_writeContext.writeFieldName(fieldName) == JsonWriteContext.STATUS_EXPECT_VALUE) {
_reportError("Can not write a field name, expecting a value");
}
_writeFieldName(fieldName);
writeString(value);
}
private final void _writeFieldName(String name)
throws IOException
{
_writeScalar(name, "string", STYLE_NAME);
}
/*
/**********************************************************
/* Public API: low-level I/O
/**********************************************************
*/
@Override
public final void flush() throws IOException
{
_writer.flush();
}
@Override
public void close() throws IOException
{
if (!isClosed()) {
_emitter.emit(new DocumentEndEvent(null, null, false));
_emitter.emit(new StreamEndEvent(null, null));
super.close();
_writer.close();
}
}
/*
/**********************************************************
/* Public API: structural output
/**********************************************************
*/
@Override
public final void writeStartArray() throws IOException
{
_verifyValueWrite("start an array");
_writeContext = _writeContext.createChildArrayContext();
Boolean style = _outputOptions.getDefaultFlowStyle().getStyleBoolean();
String yamlTag = _typeId;
boolean implicit = (yamlTag == null);
String anchor = _objectId;
if (anchor != null) {
_objectId = null;
}
_emitter.emit(new SequenceStartEvent(anchor, yamlTag,
implicit, null, null, style));
}
@Override
public final void writeEndArray() throws IOException
{
if (!_writeContext.inArray()) {
_reportError("Current context not Array but "+_writeContext.typeDesc());
}
// just to make sure we don't "leak" type ids
_typeId = null;
_writeContext = _writeContext.getParent();
_emitter.emit(new SequenceEndEvent(null, null));
}
@Override
public final void writeStartObject() throws IOException
{
_verifyValueWrite("start an object");
_writeContext = _writeContext.createChildObjectContext();
Boolean style = _outputOptions.getDefaultFlowStyle().getStyleBoolean();
String yamlTag = _typeId;
boolean implicit = (yamlTag == null);
String anchor = _objectId;
if (anchor != null) {
_objectId = null;
}
_emitter.emit(new MappingStartEvent(anchor, yamlTag,
implicit, null, null, style));
}
@Override
public final void writeEndObject() throws IOException
{
if (!_writeContext.inObject()) {
_reportError("Current context not Object but "+_writeContext.typeDesc());
}
// just to make sure we don't "leak" type ids
_typeId = null;
_writeContext = _writeContext.getParent();
_emitter.emit(new MappingEndEvent(null, null));
}
/*
/**********************************************************
/* Output method implementations, textual
/**********************************************************
*/
@Override
public void writeString(String text) throws IOException,JsonGenerationException
{
if (text == null) {
writeNull();
return;
}
_verifyValueWrite("write String value");
Character style = STYLE_QUOTED;
if (Feature.MINIMIZE_QUOTES.enabledIn(_formatFeatures) && !isBooleanContent(text)) {
// If this string could be interpreted as a number, it must be quoted.
if (Feature.ALWAYS_QUOTE_NUMBERS_AS_STRINGS.enabledIn(_formatFeatures)
&& PLAIN_NUMBER_P.matcher(text).matches()) {
style = STYLE_QUOTED;
} else if (text.indexOf('\n') >= 0) {
style = STYLE_LITERAL;
} else {
style = STYLE_PLAIN;
}
} else if (Feature.LITERAL_BLOCK_STYLE.enabledIn(_formatFeatures) && text.indexOf('\n') >= 0) {
style = STYLE_LITERAL;
}
_writeScalar(text, "string", style);
}
private boolean isBooleanContent(String text) {
return text.equals("true") || text.equals("false");
}
@Override
public void writeString(char[] text, int offset, int len) throws IOException
{
writeString(new String(text, offset, len));
}
@Override
public final void writeString(SerializableString sstr)
throws IOException
{
writeString(sstr.toString());
}
@Override
public void writeRawUTF8String(byte[] text, int offset, int len)
throws IOException
{
_reportUnsupportedOperation();
}
@Override
public final void writeUTF8String(byte[] text, int offset, int len)
throws IOException
{
writeString(new String(text, offset, len, "UTF-8"));
}
/*
/**********************************************************
/* Output method implementations, unprocessed ("raw")
/**********************************************************
*/
@Override
public void writeRaw(String text) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRaw(String text, int offset, int len) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRaw(char[] text, int offset, int len) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRaw(char c) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRawValue(String text) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRawValue(String text, int offset, int len) throws IOException {
_reportUnsupportedOperation();
}
@Override
public void writeRawValue(char[] text, int offset, int len) throws IOException {
_reportUnsupportedOperation();
}
/*
/**********************************************************
/* Output method implementations, base64-encoded binary
/**********************************************************
*/
@Override
public void writeBinary(Base64Variant b64variant, byte[] data, int offset, int len) throws IOException
{
if (data == null) {
writeNull();
return;
}
_verifyValueWrite("write Binary value");
if (offset > 0 || (offset+len) != data.length) {
data = Arrays.copyOfRange(data, offset, offset+len);
}
_writeScalarBinary(b64variant, data);
}
/*
/**********************************************************
/* Output method implementations, scalars
/**********************************************************
*/
@Override
public void writeBoolean(boolean state) throws IOException
{
_verifyValueWrite("write boolean value");
_writeScalar(state ? "true" : "false", "bool", STYLE_SCALAR);
}
@Override
public void writeNumber(int i) throws IOException
{
_verifyValueWrite("write number");
_writeScalar(String.valueOf(i), "int", STYLE_SCALAR);
}
@Override
public void writeNumber(long l) throws IOException
{
// First: maybe 32 bits is enough?
if (l <= MAX_INT_AS_LONG && l >= MIN_INT_AS_LONG) {
writeNumber((int) l);
return;
}
_verifyValueWrite("write number");
_writeScalar(String.valueOf(l), "long", STYLE_SCALAR);
}
@Override
public void writeNumber(BigInteger v) throws IOException
{
if (v == null) {
writeNull();
return;
}
_verifyValueWrite("write number");
_writeScalar(String.valueOf(v.toString()), "java.math.BigInteger", STYLE_SCALAR);
}
@Override
public void writeNumber(double d) throws IOException
{
_verifyValueWrite("write number");
_writeScalar(String.valueOf(d), "double", STYLE_SCALAR);
}
@Override
public void writeNumber(float f) throws IOException
{
_verifyValueWrite("write number");
_writeScalar(String.valueOf(f), "float", STYLE_SCALAR);
}
@Override
public void writeNumber(BigDecimal dec) throws IOException
{
if (dec == null) {
writeNull();
return;
}
_verifyValueWrite("write number");
String str = isEnabled(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN) ? dec.toPlainString() : dec.toString();
_writeScalar(str, "java.math.BigDecimal", STYLE_SCALAR);
}
@Override
public void writeNumber(String encodedValue) throws IOException,JsonGenerationException, UnsupportedOperationException
{
if (encodedValue == null) {
writeNull();
return;
}
_verifyValueWrite("write number");
_writeScalar(encodedValue, "number", STYLE_SCALAR);
}
@Override
public void writeNull() throws IOException
{
_verifyValueWrite("write null value");
// no real type for this, is there?
_writeScalar("null", "object", STYLE_SCALAR);
}
/*
/**********************************************************
/* Public API, write methods, Native Ids
/**********************************************************
*/
@Override
public boolean canWriteObjectId() {
// yes, YAML does support Native Type Ids!
// 10-Sep-2014, tatu: Except as per [#23] might not want to...
return Feature.USE_NATIVE_OBJECT_ID.enabledIn(_formatFeatures);
}
@Override
public boolean canWriteTypeId() {
// yes, YAML does support Native Type Ids!
// 10-Sep-2014, tatu: Except as per [#22] might not want to...
return Feature.USE_NATIVE_TYPE_ID.enabledIn(_formatFeatures);
}
@Override
public void writeTypeId(Object id)
throws IOException
{
// should we verify there's no preceding type id?
_typeId = String.valueOf(id);
}
@Override
public void writeObjectRef(Object id)
throws IOException
{
_verifyValueWrite("write Object reference");
AliasEvent evt = new AliasEvent(String.valueOf(id), null, null);
_emitter.emit(evt);
}
@Override
public void writeObjectId(Object id)
throws IOException
{
// should we verify there's no preceding id?
_objectId = String.valueOf(id);
}
/*
/**********************************************************
/* Implementations for methods from base class
/**********************************************************
*/
@Override
protected final void _verifyValueWrite(String typeMsg)
throws IOException
{
int status = _writeContext.writeValue();
if (status == JsonWriteContext.STATUS_EXPECT_NAME) {
_reportError("Can not "+typeMsg+", expecting field name");
}
}
@Override
protected void _releaseBuffers() {
// nothing special to do...
}
/*
/**********************************************************
/* Internal methods
/**********************************************************
*/
// Implicit means that (type) tags won't be shown, right?
private final static ImplicitTuple NO_TAGS = new ImplicitTuple(true, true);
// ... and sometimes we specifically DO want explicit tag:
private final static ImplicitTuple EXPLICIT_TAGS = new ImplicitTuple(false, false);
protected void _writeScalar(String value, String type, Character style) throws IOException
{
_emitter.emit(_scalarEvent(value, style));
}
private void _writeScalarBinary(Base64Variant b64variant,
byte[] data) throws IOException
{
// 15-Dec-2017, tatu: as per [dataformats-text#62], can not use SnakeYAML's internal
// codec. Also: force use of linefeed variant if using default
if (b64variant == Base64Variants.getDefaultVariant()) {
b64variant = Base64Variants.MIME;
}
String encoded = b64variant.encode(data);
_emitter.emit(new ScalarEvent(null, TAG_BINARY, EXPLICIT_TAGS, encoded,
null, null, STYLE_BASE64));
}
protected ScalarEvent _scalarEvent(String value, Character style)
{
String yamlTag = _typeId;
if (yamlTag != null) {
_typeId = null;
}
String anchor = _objectId;
if (anchor != null) {
_objectId = null;
}
// 29-Nov-2017, tatu: Not 100% sure why we don't force explicit tags for
// type id, but trying to do so seems to double up tag output...
return new ScalarEvent(anchor, yamlTag, NO_TAGS, value,
null, null, style);
}
}