Package org.apache.avro

Class SchemaParser

java.lang.Object

org.apache.avro.SchemaParser

public class SchemaParser
extends Object

Avro schema parser for text-based formats like JSON, IDL, etc.

Parses formatted (i.e., text based) schemata from a given source using the available FormattedSchemaParser implementations, and returns the first result. This means it can transparently handle any schema format. The Avro project defines a JSON based format and an IDL format (the latter available as a separate dependency), but you can also provide your own.

The parser can handle various text based sources. If the source contains a UTF encoded latin text based format it can even detect which UTF encoding was used (UTF-8, UTF16BE, UTF16LE, UTF-32BE or UTF32LE).

See Also:

• FormattedSchemaParser
• UtfTextUtils

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	SchemaParser.ParseResult

Constructor Summary

Constructors

Constructor	Description
SchemaParser()	Create a schema parser that validates names using NameValidator.UTF_VALIDATOR.
SchemaParser(NameValidator nameValidator)	Create a schema parser with the specified name validator.

Method Summary

Modifier and Type	Method	Description
List<Schema>	getParsedNamedSchemas()	Get all parsed schemata.
SchemaParser.ParseResult	parse(File file)	Parse an Avro schema from a file.
SchemaParser.ParseResult	parse(File file, Charset charset)	Parse an Avro schema from a file written with a specific character set.
SchemaParser.ParseResult	parse(InputStream in)	Parse an Avro schema from an input stream.
SchemaParser.ParseResult	parse(InputStream in, Charset charset)	Parse an Avro schema from an input stream.
SchemaParser.ParseResult	parse(Reader in)	Parse an Avro schema from an input reader.
SchemaParser.ParseResult	parse(CharSequence text)	Parse an Avro schema from a string.
SchemaParser.ParseResult	parse(URI location, Charset charset)	Parse an Avro schema from a file written with a specific character set.
SchemaParser.ParseResult	parse(Path file)	Parse an Avro schema from a file.
SchemaParser.ParseResult	parse(Path file, Charset charset)	Parse an Avro schema from a file written with a specific character set.
static Schema	parseSingle(String schema)	Use a default SchemaParser to parse a single schema.
static Schema	parseSingle(Path schemaFile)	Use a default SchemaParser to parse a single schema from a file.
Schema	resolve(SchemaParser.ParseResult result)	Deprecated.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SchemaParser

public SchemaParser()

Create a schema parser that validates names using NameValidator.UTF_VALIDATOR. Initially, the list of known (named) schemata is empty.

SchemaParser

public SchemaParser(NameValidator nameValidator)

Create a schema parser with the specified name validator.

Initially, the list of known (named) schemata is empty.

Note: using NameValidator.STRICT_VALIDATOR to validate names is advised for maximum interoperability.

Parameters:

nameValidator - the name validator to use

Method Details

parseSingle

public static Schema parseSingle(String schema)
                          throws SchemaParseException

Use a default SchemaParser to parse a single schema. Equivalent to:

new SchemaParser().parse(schema).mainSchema()

Parameters:

schema - the formatted schema to parse

Returns:

the parsed schema

Throws:

SchemaParseException - when the schema is invalid

See Also:

• parse(CharSequence)

parseSingle

public static Schema parseSingle(Path schemaFile)
                          throws SchemaParseException,
IOException

Use a default SchemaParser to parse a single schema from a file. Equivalent to:

new SchemaParser().parse(schemaFile).mainSchema()

Parameters:

schemaFile - the formatted schema to parse

Returns:

the parsed schema

Throws:

SchemaParseException - when the schema is invalid

IOException

See Also:

• parse(Path)

parse

public SchemaParser.ParseResult parse(File file)
                               throws IOException,
SchemaParseException

Parse an Avro schema from a file. The file content is assumed to be UTF text.

Parameters:

file - the file to read

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

See Also:

• UTF detection algorithm in UtfTextUtils

parse

public SchemaParser.ParseResult parse(File file,
 Charset charset)
                               throws IOException,
SchemaParseException

Parse an Avro schema from a file written with a specific character set.

Parameters:

file - the file to read

charset - the character set of the file contents

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

parse

public SchemaParser.ParseResult parse(Path file)
                               throws IOException,
SchemaParseException

Parse an Avro schema from a file. The file content is assumed to be UTF text.

Parameters:

file - the file to read

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

See Also:

• UTF detection algorithm in UtfTextUtils

parse

public SchemaParser.ParseResult parse(Path file,
 Charset charset)
                               throws IOException,
SchemaParseException

Parse an Avro schema from a file written with a specific character set.

Parameters:

file - the file to read

charset - the character set of the file contents

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

parse

public SchemaParser.ParseResult parse(URI location,
 Charset charset)
                               throws IOException,
SchemaParseException

Parse an Avro schema from a file written with a specific character set.

Parameters:

location - the location of the schema resource

charset - the character set of the schema resource

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

parse

public SchemaParser.ParseResult parse(InputStream in)
                               throws IOException,
SchemaParseException

Parse an Avro schema from an input stream. The stream content is assumed to be UTF text. Note that the stream stays open after reading.

Parameters:

in - the stream to read

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

See Also:

• UTF detection algorithm in UtfTextUtils

parse

public SchemaParser.ParseResult parse(InputStream in,
 Charset charset)
                               throws IOException,
SchemaParseException

Parse an Avro schema from an input stream. Note that the stream stays open after reading.

Parameters:

in - the stream to read

charset - the character set of the stream contents

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

parse

public SchemaParser.ParseResult parse(Reader in)
                               throws IOException,
SchemaParseException

Parse an Avro schema from an input reader.

Parameters:

in - the stream to read

Returns:

the schema

Throws:

IOException - when the schema cannot be read

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

parse

public SchemaParser.ParseResult parse(CharSequence text)
                               throws SchemaParseException

Parse an Avro schema from a string.

Parameters:

text - the text to parse

Returns:

the schema

Throws:

SchemaParseException - if parsing the schema failed; contains suppressed underlying parse exceptions if available

getParsedNamedSchemas

public List<Schema> getParsedNamedSchemas()

Get all parsed schemata.

Returns:

all parsed schemas, in the order they were parsed

resolve

@Deprecated
public Schema resolve(SchemaParser.ParseResult result)

Deprecated.