org.gridkit.jvmtool.jackson
Class JsonGenerator

java.lang.Object
  org.gridkit.jvmtool.jackson.JsonGenerator

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

WriterBasedGenerator

public abstract class JsonGenerator
extends Object
implements Closeable

Base class that defines public API for writing JSON content. Instances are created using factory methods of a JsonFactory instance.

Author:

Tatu Saloranta

Nested Class Summary

static class

JsonGenerator.Feature Enumeration that defines all togglable features for generators.

Field Summary

protected PrettyPrinter

_cfgPrettyPrinter Object that handles pretty-printing (usually additional white space to make results more human-readable) during output.

Constructor Summary

protected

JsonGenerator()

Method Summary

abstract void	close() Method called to close this generator, so that no more content can be written.
JsonGenerator	configure(JsonGenerator.Feature f, boolean state) Method for enabling or disabling specified feature: check JsonGenerator.Feature for list of available features.
abstract JsonGenerator	disable(JsonGenerator.Feature f) Method for disabling specified features (check JsonGenerator.Feature for list of features)
abstract JsonGenerator	enable(JsonGenerator.Feature f) Method for enabling specified parser features: check JsonGenerator.Feature for list of available features.
abstract void	flush() Method called to flush any buffered content to the underlying target (output stream, writer), and to flush the target itself as well.
CharacterEscapes	getCharacterEscapes() Method for accessing custom escapes factory uses for JsonGenerators it creates.
int	getHighestEscapedChar() Accessor method for testing what is the highest unescaped character configured for this generator.
abstract JsonStreamContext	getOutputContext()
Object	getOutputTarget() Method that can be used to get access to object that is used as target for generated output; this is usually either OutputStream or Writer, depending on what generator was constructed with.
abstract boolean	isClosed() Method that can be called to determine whether this generator is closed or not.
abstract boolean	isEnabled(JsonGenerator.Feature f) Method for checking whether given feature is enabled.
JsonGenerator	setCharacterEscapes(CharacterEscapes esc) Method for defining custom escapes factory uses for JsonGenerators it creates.
JsonGenerator	setHighestNonEscapedChar(int charCode) Method that can be called to request that generator escapes all character codes above specified code point (if positive value); or, to not escape any characters except for ones that must be escaped for the data format (if -1).
JsonGenerator	setPrettyPrinter(PrettyPrinter pp) Method for setting a custom pretty printer, which is usually used to add indentation for improved human readability.
abstract JsonGenerator	useDefaultPrettyPrinter() Convenience method for enabling pretty-printing using the default pretty printer (org.codehaus.jackson.util.DefaultPrettyPrinter).
void	writeArrayFieldStart(String fieldName) Convenience method for outputting a field entry ("member") (that will contain a JSON Array value), and the START_ARRAY marker.
abstract void	writeBoolean(boolean state) Method for outputting literal Json boolean value (one of Strings 'true' and 'false').
void	writeBooleanField(String fieldName, boolean value) Convenience method for outputting a field entry ("member") that has a boolean value.
abstract void	writeEndArray() Method for writing closing marker of a JSON Array value (character ']'; plus possible white space decoration if pretty-printing is enabled).
abstract void	writeEndObject() Method for writing closing marker of a JSON Object value (character '}'; plus possible white space decoration if pretty-printing is enabled).
abstract void	writeFieldName(String name) Method for writing a field name (JSON String surrounded by double quotes: syntactically identical to a JSON String value), possibly decorated by white space if pretty-printing is enabled.
abstract void	writeNull() Method for outputting literal Json null value.
void	writeNullField(String fieldName) Convenience method for outputting a field entry ("member") that has JSON literal value null.
abstract void	writeNumber(BigDecimal dec) Method for outputting indicate Json numeric value.
abstract void	writeNumber(BigInteger v) Method for outputting given value as Json number.
abstract void	writeNumber(double d) Method for outputting indicate Json numeric value.
abstract void	writeNumber(float f) Method for outputting indicate Json numeric value.
abstract void	writeNumber(int v) Method for outputting given value as Json number.
abstract void	writeNumber(long v) Method for outputting given value as Json number.
abstract void	writeNumber(String encodedValue) Write method that can be used for custom numeric types that can not be (easily?) converted to "standard" Java number types.
void	writeNumberField(String fieldName, BigDecimal value) Convenience method for outputting a field entry ("member") that has the specified numeric value.
void	writeNumberField(String fieldName, double value) Convenience method for outputting a field entry ("member") that has the specified numeric value.
void	writeNumberField(String fieldName, float value) Convenience method for outputting a field entry ("member") that has the specified numeric value.
void	writeNumberField(String fieldName, int value) Convenience method for outputting a field entry ("member") that has the specified numeric value.
void	writeNumberField(String fieldName, long value) Convenience method for outputting a field entry ("member") that has the specified numeric value.
void	writeObjectFieldStart(String fieldName) Convenience method for outputting a field entry ("member") (that will contain a JSON Object value), and the START_OBJECT marker.
abstract void	writeRaw(char c) Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such).
abstract void	writeRaw(char[] text, int offset, int len) Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such).
abstract void	writeRaw(String text) Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such).
abstract void	writeRaw(String text, int offset, int len) Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such).
abstract void	writeRawUTF8String(byte[] text, int offset, int length) Method similar to writeString(String) but that takes as its input a UTF-8 encoded String that is to be output as-is, without additional escaping (type of which depends on data format; backslashes for JSON).
abstract void	writeRawValue(char[] text, int offset, int len)
abstract void	writeRawValue(String text) Method that will force generator to copy input text verbatim without any modifications, but assuming it must constitute a single legal JSON value (number, string, boolean, null, Array or List).
abstract void	writeRawValue(String text, int offset, int len)
abstract void	writeStartArray() Method for writing starting marker of a JSON Array value (character '['; plus possible white space decoration if pretty-printing is enabled).
abstract void	writeStartObject() Method for writing starting marker of a JSON Object value (character '{'; plus possible white space decoration if pretty-printing is enabled).
abstract void	writeString(char[] text, int offset, int len) Method for outputting a String value.
abstract void	writeString(String text) Method for outputting a String value.
void	writeStringField(String fieldName, String value) Convenience method for outputting a field entry ("member") that has a String value.
abstract void	writeUTF8String(byte[] text, int offset, int length) Method similar to writeString(String) but that takes as its input a UTF-8 encoded String which has not been escaped using whatever escaping scheme data format requires (for JSON that is backslash-escaping for control characters and double-quotes; for other formats something else).

Methods inherited from class java.lang.Object

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

Field Detail

_cfgPrettyPrinter

protected PrettyPrinter _cfgPrettyPrinter

Object that handles pretty-printing (usually additional white space to make results more human-readable) during output. If null, no pretty-printing is done.

Constructor Detail

JsonGenerator

protected JsonGenerator()

Method Detail

getOutputTarget

public Object getOutputTarget()

Method that can be used to get access to object that is used as target for generated output; this is usually either OutputStream or Writer, depending on what generator was constructed with. Note that returned value may be null in some cases; including case where implementation does not want to exposed raw source to caller. In cases where output has been decorated, object returned here is the decorated version; this allows some level of interaction between users of generator and decorator object.

In general use of this accessor should be considered as "last effort", i.e. only used if no other mechanism is applicable.

Since:

1.8

enable

public abstract JsonGenerator enable(JsonGenerator.Feature f)

Method for enabling specified parser features: check JsonGenerator.Feature for list of available features.

Returns:

Generator itself (this), to allow chaining

Since:

1.2

disable

public abstract JsonGenerator disable(JsonGenerator.Feature f)

Method for disabling specified features (check JsonGenerator.Feature for list of features)

Returns:

Generator itself (this), to allow chaining

Since:

1.2

configure

public JsonGenerator configure(JsonGenerator.Feature f,
                               boolean state)

Method for enabling or disabling specified feature: check JsonGenerator.Feature for list of available features.

Returns:

Generator itself (this), to allow chaining

Since:

1.2

isEnabled

public abstract boolean isEnabled(JsonGenerator.Feature f)

Method for checking whether given feature is enabled. Check JsonGenerator.Feature for list of available features.

Since:

1.2

setPrettyPrinter

public JsonGenerator setPrettyPrinter(PrettyPrinter pp)

Method for setting a custom pretty printer, which is usually used to add indentation for improved human readability. By default, generator does not do pretty printing.

To use the default pretty printer that comes with core Jackson distribution, call useDefaultPrettyPrinter() instead.

Returns:

Generator itself (this), to allow chaining

useDefaultPrettyPrinter

public abstract JsonGenerator useDefaultPrettyPrinter()

Convenience method for enabling pretty-printing using the default pretty printer (org.codehaus.jackson.util.DefaultPrettyPrinter).

Returns:

Generator itself (this), to allow chaining

setHighestNonEscapedChar

public JsonGenerator setHighestNonEscapedChar(int charCode)

Method that can be called to request that generator escapes all character codes above specified code point (if positive value); or, to not escape any characters except for ones that must be escaped for the data format (if -1). To force escaping of all non-ASCII characters, for example, this method would be called with value of 127.

Note that generators are NOT required to support setting of value higher than 127, because there are other ways to affect quoting (or lack thereof) of character codes between 0 and 127. Not all generators support concept of escaping, either; if so, calling this method will have no effect.

Default implementation does nothing; sub-classes need to redefine it according to rules of supported data format.

Parameters:

charCode - Either -1 to indicate that no additional escaping is to be done; or highest code point not to escape (meaning higher ones will be), if positive value.

Since:

1.8

getHighestEscapedChar

public int getHighestEscapedChar()

Accessor method for testing what is the highest unescaped character configured for this generator. This may be either positive value (when escaping configuration has been set and is in effect), or 0 to indicate that no additional escaping is in effect. Some generators may not support additional escaping: for example, generators for binary formats that do not use escaping should simply return 0.

Returns:

Currently active limitation for highest non-escaped character, if defined; or -1 to indicate no additional escaping is performed.

getCharacterEscapes

public CharacterEscapes getCharacterEscapes()

Method for accessing custom escapes factory uses for JsonGenerators it creates.

Since:

1.8

setCharacterEscapes

public JsonGenerator setCharacterEscapes(CharacterEscapes esc)

Method for defining custom escapes factory uses for JsonGenerators it creates.

Since:

1.8

writeStartArray

public abstract void writeStartArray()
                              throws IOException,
                                     JsonGenerationException

Method for writing starting marker of a JSON Array value (character '['; plus possible white space decoration if pretty-printing is enabled).

Array values can be written in any context where values are allowed: meaning everywhere except for when a field name is expected.

Throws:

IOException

JsonGenerationException

writeEndArray

public abstract void writeEndArray()
                            throws IOException,
                                   JsonGenerationException

Method for writing closing marker of a JSON Array value (character ']'; plus possible white space decoration if pretty-printing is enabled).

Marker can be written if the innermost structured type is Array.

Throws:

IOException

JsonGenerationException

writeStartObject

public abstract void writeStartObject()
                               throws IOException,
                                      JsonGenerationException

Method for writing starting marker of a JSON Object value (character '{'; plus possible white space decoration if pretty-printing is enabled).

Object values can be written in any context where values are allowed: meaning everywhere except for when a field name is expected.

Throws:

IOException

JsonGenerationException

writeEndObject

public abstract void writeEndObject()
                             throws IOException,
                                    JsonGenerationException

Method for writing closing marker of a JSON Object value (character '}'; plus possible white space decoration if pretty-printing is enabled).

Marker can be written if the innermost structured type is Object, and the last written event was either a complete value, or START-OBJECT marker (see JSON specification for more details).

Throws:

IOException

JsonGenerationException

writeFieldName

public abstract void writeFieldName(String name)
                             throws IOException,
                                    JsonGenerationException

Method for writing a field name (JSON String surrounded by double quotes: syntactically identical to a JSON String value), possibly decorated by white space if pretty-printing is enabled.

Field names can only be written in Object context (check out JSON specification for details), when field name is expected (field names alternate with values).

Throws:

IOException

JsonGenerationException

writeString

public abstract void writeString(String text)
                          throws IOException,
                                 JsonGenerationException

Method for outputting a String value. Depending on context this means either array element, (object) field value or a stand alone String; but in all cases, String will be surrounded in double quotes, and contents will be properly escaped as required by JSON specification.

Throws:

IOException

JsonGenerationException

writeString

public abstract void writeString(char[] text,
                                 int offset,
                                 int len)
                          throws IOException,
                                 JsonGenerationException

Method for outputting a String value. Depending on context this means either array element, (object) field value or a stand alone String; but in all cases, String will be surrounded in double quotes, and contents will be properly escaped as required by JSON specification.

Throws:

IOException

JsonGenerationException

writeRawUTF8String

public abstract void writeRawUTF8String(byte[] text,
                                        int offset,
                                        int length)
                                 throws IOException,
                                        JsonGenerationException

Method similar to writeString(String) but that takes as its input a UTF-8 encoded String that is to be output as-is, without additional escaping (type of which depends on data format; backslashes for JSON). However, quoting that data format requires (like double-quotes for JSON) will be added around the value if and as necessary.

Note that some backends may choose not to support this method: for example, if underlying destination is a Writer using this method would require UTF-8 decoding. If so, implementation may instead choose to throw a UnsupportedOperationException due to ineffectiveness of having to decode input.

Throws:

IOException

JsonGenerationException

Since:

1.7

writeUTF8String

public abstract void writeUTF8String(byte[] text,
                                     int offset,
                                     int length)
                              throws IOException,
                                     JsonGenerationException

Method similar to writeString(String) but that takes as its input a UTF-8 encoded String which has not been escaped using whatever escaping scheme data format requires (for JSON that is backslash-escaping for control characters and double-quotes; for other formats something else). This means that textual JSON backends need to check if value needs JSON escaping, but otherwise can just be copied as is to output. Also, quoting that data format requires (like double-quotes for JSON) will be added around the value if and as necessary.

Note that some backends may choose not to support this method: for example, if underlying destination is a Writer using this method would require UTF-8 decoding. In this case generator implementation may instead choose to throw a UnsupportedOperationException due to ineffectiveness of having to decode input.

Throws:

IOException

JsonGenerationException

Since:

1.7

writeRaw

public abstract void writeRaw(String text)
                       throws IOException,
                              JsonGenerationException

Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such). If such separators are desired, use writeRawValue(String) instead.

Note that not all generator implementations necessarily support such by-pass methods: those that do not will throw UnsupportedOperationException.

Throws:

IOException

JsonGenerationException

writeRaw

public abstract void writeRaw(String text,
                              int offset,
                              int len)
                       throws IOException,
                              JsonGenerationException

Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such). If such separators are desired, use writeRawValue(String) instead.

Note that not all generator implementations necessarily support such by-pass methods: those that do not will throw UnsupportedOperationException.

Throws:

IOException

JsonGenerationException

writeRaw

public abstract void writeRaw(char[] text,
                              int offset,
                              int len)
                       throws IOException,
                              JsonGenerationException

Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such). If such separators are desired, use writeRawValue(String) instead.

Note that not all generator implementations necessarily support such by-pass methods: those that do not will throw UnsupportedOperationException.

Throws:

IOException

JsonGenerationException

writeRaw

public abstract void writeRaw(char c)
                       throws IOException,
                              JsonGenerationException

Method that will force generator to copy input text verbatim with no modifications (including that no escaping is done and no separators are added even if context [array, object] would otherwise require such). If such separators are desired, use writeRawValue(String) instead.

Note that not all generator implementations necessarily support such by-pass methods: those that do not will throw UnsupportedOperationException.

Throws:

IOException

JsonGenerationException

writeRawValue

public abstract void writeRawValue(String text)
                            throws IOException,
                                   JsonGenerationException

Method that will force generator to copy input text verbatim without any modifications, but assuming it must constitute a single legal JSON value (number, string, boolean, null, Array or List). Assuming this, proper separators are added if and as needed (comma or colon), and generator state updated to reflect this.

Throws:

IOException

JsonGenerationException

writeRawValue

public abstract void writeRawValue(String text,
                                   int offset,
                                   int len)
                            throws IOException,
                                   JsonGenerationException

Throws:

IOException

JsonGenerationException

writeRawValue

public abstract void writeRawValue(char[] text,
                                   int offset,
                                   int len)
                            throws IOException,
                                   JsonGenerationException

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(int v)
                          throws IOException,
                                 JsonGenerationException

Method for outputting given value as Json number. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(long v)
                          throws IOException,
                                 JsonGenerationException

Method for outputting given value as Json number. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(BigInteger v)
                          throws IOException,
                                 JsonGenerationException

Method for outputting given value as Json number. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(double d)
                          throws IOException,
                                 JsonGenerationException

Method for outputting indicate Json numeric value. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(float f)
                          throws IOException,
                                 JsonGenerationException

Method for outputting indicate Json numeric value. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(BigDecimal dec)
                          throws IOException,
                                 JsonGenerationException

Method for outputting indicate Json numeric value. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNumber

public abstract void writeNumber(String encodedValue)
                          throws IOException,
                                 JsonGenerationException,
                                 UnsupportedOperationException

Write method that can be used for custom numeric types that can not be (easily?) converted to "standard" Java number types. Because numbers are not surrounded by double quotes, regular writeString(java.lang.String) method can not be used; nor writeRaw(java.lang.String) because that does not properly handle value separators needed in Array or Object contexts.

Note: because of lack of type safety, some generator implementations may not be able to implement this method. For example, if a binary json format is used, it may require type information for encoding; similarly for generator-wrappers around Java objects or Json nodes. If implementation does not implement this method, it needs to throw UnsupportedOperationException.

Throws:

IOException

JsonGenerationException

UnsupportedOperationException

writeBoolean

public abstract void writeBoolean(boolean state)
                           throws IOException,
                                  JsonGenerationException

Method for outputting literal Json boolean value (one of Strings 'true' and 'false'). Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeNull

public abstract void writeNull()
                        throws IOException,
                               JsonGenerationException

Method for outputting literal Json null value. Can be called in any context where a value is expected (Array value, Object field value, root-level value). Additional white space may be added around the value if pretty-printing is enabled.

Throws:

IOException

JsonGenerationException

writeStringField

public void writeStringField(String fieldName,
                             String value)
                      throws IOException,
                             JsonGenerationException

Convenience method for outputting a field entry ("member") that has a String value. Equivalent to:

  writeFieldName(fieldName);
  writeString(value);

Note: many performance-sensitive implementations override this method

Throws:

IOException

JsonGenerationException

writeBooleanField

public final void writeBooleanField(String fieldName,
                                    boolean value)
                             throws IOException,
                                    JsonGenerationException

Convenience method for outputting a field entry ("member") that has a boolean value. Equivalent to:

  writeFieldName(fieldName);
  writeBoolean(value);

Throws:

IOException

JsonGenerationException

writeNullField

public final void writeNullField(String fieldName)
                          throws IOException,
                                 JsonGenerationException

Convenience method for outputting a field entry ("member") that has JSON literal value null. Equivalent to:

  writeFieldName(fieldName);
  writeNull();

Throws:

IOException

JsonGenerationException

writeNumberField

public final void writeNumberField(String fieldName,
                                   int value)
                            throws IOException,
                                   JsonGenerationException

Convenience method for outputting a field entry ("member") that has the specified numeric value. Equivalent to:

  writeFieldName(fieldName);
  writeNumber(value);

Throws:

IOException

JsonGenerationException

writeNumberField

public final void writeNumberField(String fieldName,
                                   long value)
                            throws IOException,
                                   JsonGenerationException

Convenience method for outputting a field entry ("member") that has the specified numeric value. Equivalent to:

  writeFieldName(fieldName);
  writeNumber(value);

Throws:

IOException

JsonGenerationException

writeNumberField

public final void writeNumberField(String fieldName,
                                   double value)
                            throws IOException,
                                   JsonGenerationException

Convenience method for outputting a field entry ("member") that has the specified numeric value. Equivalent to:

  writeFieldName(fieldName);
  writeNumber(value);

Throws:

IOException

JsonGenerationException

writeNumberField

public final void writeNumberField(String fieldName,
                                   float value)
                            throws IOException,
                                   JsonGenerationException

Convenience method for outputting a field entry ("member") that has the specified numeric value. Equivalent to:

  writeFieldName(fieldName);
  writeNumber(value);

Throws:

IOException

JsonGenerationException

writeNumberField

public final void writeNumberField(String fieldName,
                                   BigDecimal value)
                            throws IOException,
                                   JsonGenerationException

Convenience method for outputting a field entry ("member") that has the specified numeric value. Equivalent to:

  writeFieldName(fieldName);
  writeNumber(value);

Throws:

IOException

JsonGenerationException

writeArrayFieldStart

public final void writeArrayFieldStart(String fieldName)
                                throws IOException,
                                       JsonGenerationException

Convenience method for outputting a field entry ("member") (that will contain a JSON Array value), and the START_ARRAY marker. Equivalent to:

  writeFieldName(fieldName);
  writeStartArray();

Note: caller still has to take care to close the array (by calling {#link #writeEndArray}) after writing all values of the value Array.

Throws:

IOException

JsonGenerationException

writeObjectFieldStart

public final void writeObjectFieldStart(String fieldName)
                                 throws IOException,
                                        JsonGenerationException

Convenience method for outputting a field entry ("member") (that will contain a JSON Object value), and the START_OBJECT marker. Equivalent to:

  writeFieldName(fieldName);
  writeStartObject();

Note: caller still has to take care to close the Object (by calling {#link #writeEndObject}) after writing all entries of the value Object.

Throws:

IOException

JsonGenerationException

getOutputContext

public abstract JsonStreamContext getOutputContext()

Returns:

Context object that can give information about logical position within generated json content.

flush

public abstract void flush()
                    throws IOException

Method called to flush any buffered content to the underlying target (output stream, writer), and to flush the target itself as well.

Throws:

IOException

isClosed

public abstract boolean isClosed()

Method that can be called to determine whether this generator is closed or not. If it is closed, no more output can be done.

close

public abstract void close()
                    throws IOException

Method called to close this generator, so that no more content can be written.

Whether the underlying target (stream, writer) gets closed depends on whether this generator either manages the target (i.e. is the only one with access to the target -- case if caller passes a reference to the resource such as File, but not stream); or has feature JsonGenerator.Feature.AUTO_CLOSE_TARGET enabled. If either of above is true, the target is also closed. Otherwise (not managing, feature not enabled), target is not closed.

Specified by:

close in interface Closeable

Throws:

IOException