org.marc4j.util

Class JsonParser

java.lang.Object

org.marc4j.util.JsonParser

public class JsonParser
extends Object

A pull-event parser for JSON data.

Note that the event and member values are only valid while the parser is not searching for the next event.

Threading Design : [x] Single Threaded [ ] Thread-safe [ ] Immutable [ ] Isolated

Since:

Build 2007.0726.0032

Author:

Lawrence Dol

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JsonParser.Escape
static class	JsonParser.Location

Field Summary

Fields

Modifier and Type	Field and Description
static int	EVT_ARRAY_BEGIN Returned from next() when the beginning of a declared array is read.
static int	EVT_ARRAY_ENDED Returned from next() when the end of a declared array is read.
static int	EVT_INPUT_ENDED Returned from next() when the end of the input source is reached.
static int	EVT_OBJECT_BEGIN Returned from next() when the beginning of an object is read.
static int	EVT_OBJECT_ENDED Returned from next() when the end of an object is read.
static int	EVT_OBJECT_MEMBER Returned from next() when a simple object member (Name:Value pair or array element) is read.
static int	OPT_ALL All options on.
static int	OPT_CONFIG Recommended for config parsing mode - OPT_UNQUOTED_KEYWORDS, OPT_EOL_IS_COMMA, OPT_MULTILINE_COMMENTS, OPT_SINGLE_QUOTE_STRINGS, OPT_INTERN_KEYWORDS, OPT_INTERN_VALUES.
static int	OPT_EOL_IS_COMMA Option to allow an end-of-line to be treated as a comma.
static int	OPT_INTERN_KEYWORDS Option to cause keywords to be interned (String.intern()) - this is not a JSON compliance option.
static int	OPT_INTERN_VALUES Option to cause keywords to be interned (String.intern()) - this is not a JSON compliance option.
static int	OPT_MESSAGING Recommended options for messaging parsing mode - OPT_UNQUOTED_KEYWORDS, OPT_INTERN_KEYWORDS.
static int	OPT_MULTILINE_COMMENTS Option to allow multiline comments using /* and */.
static int	OPT_MULTILINE_STRINGS Option to allow mutiline strings - this permits strings to be broken over multiple lines in an unambigous manner.
static int	OPT_PRELOAD_INPUT Option to preload file input data when the input source is set - this is not a JSON compliance option.
static int	OPT_SINGLE_QUOTE_STRINGS Option to allow single-quotes to be used for strings.
static int	OPT_STRICT All options off.
static int	OPT_UNQUOTED_KEYWORDS Option to allow keywords to be unquoted.

Constructor Summary

Constructors

Constructor and Description
JsonParser(int opt) Construct a JSON parser from a character input source.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Reset this parser, and clear any internal caches or pools used to improve performance.
static Object	createTypedValue(String val) Create a typed member value applying JSON typing rules.
int	getEventCode() Get the code for the current event.
int	getEventColumn() Get the input source column number for the current event.
int	getEventLine() Get the input source line number for the current event.
JsonParser.Location	getEventLocation() Get the input source location for the current event.
String	getEventName() Get the name for the current event.
static String	getEventName(int cod) Get a text name for the event code.
JsonParser.Location	getInputLocation() Get the current location in the input source.
String	getInputName() Get the name assigned to the input source at construction.
boolean	getMemberArray() Get the current object member array flag.
String	getMemberName() Get the current object member name.
String	getMemberValue() Get the current object member value (valid only if the current event is EVT_OBJECT_MEMBER).
String	getObjectName() Get the name of the current object.
static Object	getTypedMemberValue(String val) Get the current object member value applying JSON typing rules (valid only if the current event is EVT_OBJECT_MEMBER).
static boolean	isQuoted(String val) Test if the member value is enclosed in text-value-indicating quotes.
int	next() Parse next event from input source.
void	reset() Reset this parser to be ready for more input after completing the parsing of some input.
JsonParser	setInput(File inpfil, String inpenc, int bufsiz) Construct a JSON parser from a file input source.
JsonParser	setInput(String inpnam, InputStream inpsrc, String inpenc, boolean inpcls) Construct a JSON parser from a byte input source.
JsonParser	setInput(String inpnam, Reader inpsrc, boolean inpcls) Construct a JSON parser from a character input source.
JsonParser	setInput(String inpfil, String inpenc, int bufsiz) Construct a JSON parser from a file input source.
void	skipArray() Skip the array that the parser is currently positioned at.
void	skipObject() Skip the object that the parser is currently positioned at.
static String	stripQuotes(String val) Strip the text-value-indicating quotes from the supplied member value, if any.

Methods inherited from class java.lang.Object

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

Field Detail

EVT_OBJECT_BEGIN

public static final int EVT_OBJECT_BEGIN

Returned from next() when the beginning of an object is read.

See Also:

Constant Field Values

EVT_OBJECT_ENDED

public static final int EVT_OBJECT_ENDED

Returned from next() when the end of an object is read.

See Also:

Constant Field Values

EVT_ARRAY_BEGIN

public static final int EVT_ARRAY_BEGIN

Returned from next() when the beginning of a declared array is read.

See Also:

Constant Field Values

EVT_ARRAY_ENDED

public static final int EVT_ARRAY_ENDED

Returned from next() when the end of a declared array is read.

See Also:

Constant Field Values

EVT_INPUT_ENDED

public static final int EVT_INPUT_ENDED

Returned from next() when the end of the input source is reached.

See Also:

Constant Field Values

EVT_OBJECT_MEMBER

public static final int EVT_OBJECT_MEMBER

Returned from next() when a simple object member (Name:Value pair or array element) is read.

See Also:

Constant Field Values

OPT_UNQUOTED_KEYWORDS

public static final int OPT_UNQUOTED_KEYWORDS

Option to allow keywords to be unquoted.

See Also:

Constant Field Values

OPT_EOL_IS_COMMA

public static final int OPT_EOL_IS_COMMA

Option to allow an end-of-line to be treated as a comma.

See Also:

Constant Field Values

OPT_MULTILINE_COMMENTS

public static final int OPT_MULTILINE_COMMENTS

Option to allow multiline comments using /* and */.

See Also:

Constant Field Values

OPT_MULTILINE_STRINGS

public static final int OPT_MULTILINE_STRINGS

Option to allow mutiline strings - this permits strings to be broken over multiple lines in an unambigous manner.

See Also:

Constant Field Values

OPT_SINGLE_QUOTE_STRINGS

public static final int OPT_SINGLE_QUOTE_STRINGS

Option to allow single-quotes to be used for strings.

See Also:

Constant Field Values

OPT_PRELOAD_INPUT

public static final int OPT_PRELOAD_INPUT

Option to preload file input data when the input source is set - this is not a JSON compliance option. Preloading file contents can be useful in order to overlap loading and processing of multiple files using a deferred processing pipeline.

See Also:

Constant Field Values

OPT_INTERN_KEYWORDS

public static final int OPT_INTERN_KEYWORDS

Option to cause keywords to be interned (String.intern()) - this is not a JSON compliance option. Interning keywords is typically a good idea and is generally recommended.

See Also:

Constant Field Values

OPT_INTERN_VALUES

public static final int OPT_INTERN_VALUES

Option to cause keywords to be interned (String.intern()) - this is not a JSON compliance option. Interning values is typically a good idea and is generally recommended.

See Also:

Constant Field Values

OPT_STRICT

public static final int OPT_STRICT

All options off. Input must conform strictly to the JSON spec.

See Also:

Constant Field Values

OPT_MESSAGING

public static final int OPT_MESSAGING

Recommended options for messaging parsing mode - OPT_UNQUOTED_KEYWORDS, OPT_INTERN_KEYWORDS.

See Also:

Constant Field Values

OPT_CONFIG

public static final int OPT_CONFIG

Recommended for config parsing mode - OPT_UNQUOTED_KEYWORDS, OPT_EOL_IS_COMMA, OPT_MULTILINE_COMMENTS, OPT_SINGLE_QUOTE_STRINGS, OPT_INTERN_KEYWORDS, OPT_INTERN_VALUES.

See Also:

Constant Field Values

OPT_ALL

public static final int OPT_ALL

All options on.

See Also:

Constant Field Values

Constructor Detail

JsonParser

public JsonParser(int opt)

Construct a JSON parser from a character input source.

Parameters:

opt - Parsing option flags, combined from OPT_xxx values.

Method Detail

close

public void close()

Reset this parser, and clear any internal caches or pools used to improve performance. The parser may be reused if desired. This should be called after completing the parsing of all input sources.

reset

public void reset()

Reset this parser to be ready for more input after completing the parsing of some input. This includes closing the input source if it was set with the flag which requests this behavior. This should be called between input sources.

getInputName

public String getInputName()

Get the name assigned to the input source at construction. This is informational only.

getInputLocation

public JsonParser.Location getInputLocation()

Get the current location in the input source.

getObjectName

public String getObjectName()

Get the name of the current object.

getEventCode

public int getEventCode()

Get the code for the current event.

getEventName

public String getEventName()

Get the name for the current event.

getEventLine

public int getEventLine()

Get the input source line number for the current event.

getEventColumn

public int getEventColumn()

Get the input source column number for the current event.

getEventLocation

public JsonParser.Location getEventLocation()

Get the input source location for the current event.

getMemberName

public String getMemberName()

Get the current object member name.

getMemberValue

public String getMemberValue()

Get the current object member value (valid only if the current event is EVT_OBJECT_MEMBER).

NOTE

All values are returned with EMCA-262 unescaping already applied. However if the value was specified in quotes it is return enclosed in quotes in order to reflect the explicit indication of a text value. This means that the string may contain ambiguous quotes when observed at face value, which situation is easily resolve using the static methods isQuoted() and stripQuotes. Alternatively, the methods getTypedMemberValue() or createTypeValue() may be used to get a Java typed object, which may be identified using instanceof.

getMemberArray

public boolean getMemberArray()

Get the current object member array flag. This indicates that the current member is an array.

getTypedMemberValue

public static Object getTypedMemberValue(String val)

Get the current object member value applying JSON typing rules (valid only if the current event is EVT_OBJECT_MEMBER). All text values must be quoted, otherwise they will be treated as a special value or number.

Actual return types are as follows:

• "..." - String value after quotes are stripped.
• true - Boolean.TRUE (not case sensitive, unlike strict JSON specification requirement)
• false - Boolean.FALSE (not case sensitive, unlike strict JSON specification requirement)
• null - null (not case sensitive, unlike strict JSON specification requirement)
• Anything else - BigDecimal (exception thrown from the BigDecimal constructor if not a valid number)

Throws:

NumberFormatException - If an unquoted value which is no null, true or false is not a valid decimal number.

setInput

public JsonParser setInput(String inpnam,
                  Reader inpsrc,
                  boolean inpcls)

Construct a JSON parser from a character input source.

Parameters:

inpnam - A text description of the source, used only for location text.

inpsrc - Input source.

inpcls - Whether to close the input source at end-of-input.

setInput

public JsonParser setInput(String inpnam,
                  InputStream inpsrc,
                  String inpenc,
                  boolean inpcls)

Construct a JSON parser from a byte input source.

Parameters:

inpnam - A text description of the source, used only for location text.

inpsrc - Input source.

inpenc - Character encoding used by the input source.

inpcls - Whether to close the input source at end-of-input.

setInput

public JsonParser setInput(String inpfil,
                  String inpenc,
                  int bufsiz)

Construct a JSON parser from a file input source.

Parameters:

inpfil - Input source.

inpenc - Character encoding used by the input source.

bufsiz - Size of input buffer for reading from the file.

setInput

public JsonParser setInput(File inpfil,
                  String inpenc,
                  int bufsiz)

Construct a JSON parser from a file input source.

Parameters:

inpfil - Input source.

inpenc - Character encoding used by the input source.

bufsiz - Size of input buffer for reading from the file.

next

public int next()

Parse next event from input source.

skipObject

public void skipObject()

Skip the object that the parser is currently positioned at. The current event must be EVT_OBJECT_BEGIN.

skipArray

public void skipArray()

Skip the array that the parser is currently positioned at. The current event must be EVT_ARRAY_BEGIN.

createTypedValue

public static Object createTypedValue(String val)

Create a typed member value applying JSON typing rules. All text values must be quoted.

Actual return types are as follows:

• true - Boolean.TRUE (not case sensitive)
• false - Boolean.FALSE (not case sensitive)
• null - Java null (not case sensitive)
• "..." - String value after quotes are stripped
• Anything else - BigDecimal (exception thrown from the BigDecimal constructor if not a valid number)

Throws:

NumberFormatException - If an unquoted value which is no null, true or false is not a valid decimal number.

getEventName

public static String getEventName(int cod)

Get a text name for the event code.

stripQuotes

public static String stripQuotes(String val)

Strip the text-value-indicating quotes from the supplied member value, if any.

isQuoted

public static boolean isQuoted(String val)

Test if the member value is enclosed in text-value-indicating quotes.