org.codehaus.jackson
Class JsonGenerator

java.lang.Object
  extended by org.codehaus.jackson.JsonGenerator
All Implemented Interfaces:
Closeable
Direct Known Subclasses:
JsonGeneratorBase

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  void copyCurrentEvent(JsonParser jp)
          Method for copying contents of the current event that the given parser instance points to.
abstract  void copyCurrentStructure(JsonParser jp)
          Method for copying contents of the current event and following events that it encloses the given parser instance points to.
abstract  JsonGenerator disable(JsonGenerator.Feature f)
          Method for disabling specified features (check JsonGenerator.Feature for list of features)
 void disableFeature(JsonGenerator.Feature f)
           
abstract  JsonGenerator enable(JsonGenerator.Feature f)
          Method for enabling specified parser features: check JsonGenerator.Feature for list of available features.
 void enableFeature(JsonGenerator.Feature f)
           
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.
abstract  ObjectCodec getCodec()
          Method for accessing the object used for writing Java object as Json content (using method writeObject(java.lang.Object)).
abstract  JsonStreamContext getOutputContext()
           
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.
 boolean isFeatureEnabled(JsonGenerator.Feature f)
           
abstract  JsonGenerator setCodec(ObjectCodec oc)
          Method that can be called to set or reset the object to use for writing Java objects as JsonContent (using method writeObject(java.lang.Object)).
 void setFeature(JsonGenerator.Feature f, boolean state)
           
 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 (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 writeBinary(Base64Variant b64variant, byte[] data, int offset, int len)
          Method that will output given chunk of binary data as base64 encoded, as a complete String value (surrounded by double quotes).
 void writeBinary(byte[] data)
          Similar to writeBinary(Base64Variant,byte[],int,int), but assumes default to using the Jackson default Base64 variant (which is Base64Variants.MIME_NO_LINEFEEDS).
 void writeBinary(byte[] data, int offset, int len)
          Similar to writeBinary(Base64Variant,byte[],int,int), but default to using the Jackson default Base64 variant (which is Base64Variants.MIME_NO_LINEFEEDS).
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.
abstract  void writeObject(Object pojo)
          Method for writing given Java object (POJO) as Json.
 void writeObjectField(String fieldName, Object pojo)
          Convenience method for outputting a field entry ("member") that has contents of specific Java object as its 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)
           
abstract  void writeRaw(char[] text, int offset, int len)
           
abstract  void writeRaw(String text)
          Fallback method which can be used to make generator copy input text verbatim with no modifications (including that no quoting 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)
           
abstract  void writeRawValue(char[] text, int offset, int len)
           
abstract  void writeRawValue(String text)
          Fallback method which can be used to make generator 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)
           
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 writeTree(JsonNode rootNode)
          Method for writing given Json tree (expressed as a tree where given JsonNode is the root) using this generator.
 
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

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

setCodec

public abstract JsonGenerator setCodec(ObjectCodec oc)
Method that can be called to set or reset the object to use for writing Java objects as JsonContent (using method writeObject(java.lang.Object)).

Returns:
Generator itself (this), to allow chaining

getCodec

public abstract ObjectCodec getCodec()
Method for accessing the object used for writing Java object as Json content (using method writeObject(java.lang.Object)).


enableFeature

public void enableFeature(JsonGenerator.Feature f)

disableFeature

public void disableFeature(JsonGenerator.Feature f)

setFeature

public void setFeature(JsonGenerator.Feature f,
                       boolean state)

isFeatureEnabled

public boolean isFeatureEnabled(JsonGenerator.Feature f)

setPrettyPrinter

public final 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 (DefaultPrettyPrinter).

Returns:
Generator itself (this), to allow chaining

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
Throws:
IOException
JsonGenerationException

writeRaw

public abstract void writeRaw(String text)
                       throws IOException,
                              JsonGenerationException
Fallback method which can be used to make generator copy input text verbatim with no modifications (including that no quoting 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.

Throws:
IOException
JsonGenerationException

writeRaw

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

writeRaw

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

writeRaw

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

writeRawValue

public abstract void writeRawValue(String text)
                            throws IOException,
                                   JsonGenerationException
Fallback method which can be used to make generator 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

writeBinary

public abstract void writeBinary(Base64Variant b64variant,
                                 byte[] data,
                                 int offset,
                                 int len)
                          throws IOException,
                                 JsonGenerationException
Method that will output given chunk of binary data as base64 encoded, as a complete String value (surrounded by double quotes). This method defaults

Note: because Json Strings can not contain unescaped linefeeds, if linefeeds are included (as per last argument), they must be escaped. This adds overhead for decoding without improving readability. Alternatively if linefeeds are not included, resulting String value may violate the requirement of base64 RFC which mandates line-length of 76 characters and use of linefeeds. However, all JsonParser implementations are required to accept such "long line base64"; as do typical production-level base64 decoders.

Parameters:
b64variant - Base64 variant to use: defines details such as whether padding is used (and if so, using which character); what is the maximum line length before adding linefeed, and also the underlying alphabet to use.
Throws:
IOException
JsonGenerationException

writeBinary

public final void writeBinary(byte[] data,
                              int offset,
                              int len)
                       throws IOException,
                              JsonGenerationException
Similar to writeBinary(Base64Variant,byte[],int,int), but default to using the Jackson default Base64 variant (which is Base64Variants.MIME_NO_LINEFEEDS).

Throws:
IOException
JsonGenerationException

writeBinary

public final void writeBinary(byte[] data)
                       throws IOException,
                              JsonGenerationException
Similar to writeBinary(Base64Variant,byte[],int,int), but assumes default to using the Jackson default Base64 variant (which is Base64Variants.MIME_NO_LINEFEEDS). Also assumes that whole byte array is to be output.

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

writeObject

public abstract void writeObject(Object pojo)
                          throws IOException,
                                 JsonProcessingException
Method for writing given Java object (POJO) as Json. Exactly how the object gets written depends on object in question (ad on codec, its configuration); for most beans it will result in Json object, but for others Json array, or String or numeric value (and for nulls, Json null literal. NOTE: generator must have its object codec set to non-null value; for generators created by a mapping factory this is the case, for others not.

Throws:
IOException
JsonProcessingException

writeTree

public abstract void writeTree(JsonNode rootNode)
                        throws IOException,
                               JsonProcessingException
Method for writing given Json tree (expressed as a tree where given JsonNode is the root) using this generator. This will generally just call writeObject(java.lang.Object) with given node, but is added for convenience and to make code more explicit in cases where it deals specifically with trees.

Throws:
IOException
JsonProcessingException

writeStringField

public final 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);

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

writeObjectField

public final void writeObjectField(String fieldName,
                                   Object pojo)
                            throws IOException,
                                   JsonProcessingException
Convenience method for outputting a field entry ("member") that has contents of specific Java object as its value. Equivalent to:
  writeFieldName(fieldName);
  writeObject(pojo);

Throws:
IOException
JsonProcessingException

copyCurrentEvent

public abstract void copyCurrentEvent(JsonParser jp)
                               throws IOException,
                                      JsonProcessingException
Method for copying contents of the current event that the given parser instance points to. Note that the method will not copy any other events, such as events contained within Json Array or Object structures.

Calling this method will not advance the given parser, although it may cause parser to internally process more data (if it lazy loads contents of value events, for example)

Throws:
IOException
JsonProcessingException

copyCurrentStructure

public abstract void copyCurrentStructure(JsonParser jp)
                                   throws IOException,
                                          JsonProcessingException
Method for copying contents of the current event and following events that it encloses the given parser instance points to.

So what constitutes enclosing? Here is the list of events that have associated enclosed events that will get copied:

After calling this method, parser will point to the last event that was copied. This will either be the event parser already pointed to (if there were no enclosed events), or the last enclosed event copied.

Throws:
IOException
JsonProcessingException

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