org.codehaus.jackson
Class JsonParser

java.lang.Object
  extended by org.codehaus.jackson.JsonParser
All Implemented Interfaces:
Closeable
Direct Known Subclasses:
JsonParserBase, JsonParserDelegate, TokenBuffer.Parser, TreeTraversingParser

public abstract class JsonParser
extends Object
implements Closeable

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

Author:
Tatu Saloranta

Nested Class Summary
static class JsonParser.Feature
          Enumeration that defines all togglable features for parsers.
static class JsonParser.NumberType
          Enumeration of possible "native" (optimal) types that can be used for numbers.
 
Field Summary
protected  JsonToken _currToken
          Last token retrieved via nextToken(), if any.
protected  int _features
          Bit flag composed of bits that indicate which JsonParser.Features are enabled.
protected  JsonToken _lastClearedToken
          Last cleared token, if any: that is, value that was in effect when clearCurrentToken() was called.
 
Constructor Summary
protected JsonParser()
           
 
Method Summary
protected  JsonParseException _constructError(String msg)
          Helper method for constructing JsonParseExceptions based on current state of the parser
 void clearCurrentToken()
          Method called to "consume" the current token by effectively removing it so that hasCurrentToken() returns false, and getCurrentToken() null).
abstract  void close()
          Closes the parser so that no further iteration or data access can be made; will also close the underlying input source if parser either owns the input source, or feature JsonParser.Feature.AUTO_CLOSE_SOURCE is enabled.
 JsonParser configure(JsonParser.Feature f, boolean state)
          Method for enabling or disabling specified feature (check JsonParser.Feature for list of features)
 JsonParser disable(JsonParser.Feature f)
          Method for disabling specified feature (check JsonParser.Feature for list of features)
 void disableFeature(JsonParser.Feature f)
          Deprecated. Use disable(Feature) instead
 JsonParser enable(JsonParser.Feature f)
          Method for enabling specified parser feature (check JsonParser.Feature for list of features)
 void enableFeature(JsonParser.Feature f)
          Deprecated. Use enable(Feature) instead
abstract  BigInteger getBigIntegerValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can not be used as a Java long primitive type due to its magnitude.
 byte[] getBinaryValue()
          Convenience alternative to getBinaryValue(Base64Variant) that defaults to using Base64Variants.getDefaultVariant() as the default encoding.
abstract  byte[] getBinaryValue(Base64Variant b64variant)
          Method that can be used to read (and consume -- results may not be accessible using other methods after the call) base64-encoded binary data included in the current textual json value.
 boolean getBooleanValue()
          Convenience accessor that can be called when the current token is JsonToken.VALUE_TRUE or JsonToken.VALUE_FALSE.
 byte getByteValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java byte primitive type.
abstract  ObjectCodec getCodec()
          Accessor for ObjectCodec associated with this parser, if any.
abstract  JsonLocation getCurrentLocation()
          Method that returns location of the last processed character; usually for error reporting purposes.
abstract  String getCurrentName()
          Method that can be called to get the name associated with the current token: for JsonToken.FIELD_NAMEs it will be the same as what getText() returns; for field values it will be preceding field name; and for others (array values, root-level values) null.
 JsonToken getCurrentToken()
          Accessor to find which token parser currently points to, if any; null will be returned if none.
abstract  BigDecimal getDecimalValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT or JsonToken.VALUE_NUMBER_INT.
abstract  double getDoubleValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT and it can be expressed as a Java double primitive type.
 Object getEmbeddedObject()
          Accessor that can be called if (and only if) the current token is JsonToken.VALUE_EMBEDDED_OBJECT.
abstract  float getFloatValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT and it can be expressed as a Java float primitive type.
abstract  int getIntValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java int primitive type.
 JsonToken getLastClearedToken()
          Method that can be called to get the last token that was cleared using clearCurrentToken().
abstract  long getLongValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a Java long primitive type.
abstract  JsonParser.NumberType getNumberType()
          If current token is of type JsonToken.VALUE_NUMBER_INT or JsonToken.VALUE_NUMBER_FLOAT, returns one of JsonParser.NumberType constants; otherwise returns null.
abstract  Number getNumberValue()
          Generic number value accessor method that will work for all kinds of numeric values.
abstract  JsonStreamContext getParsingContext()
          Method that can be used to access current parsing context reader is in.
 short getShortValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java short primitive type.
abstract  String getText()
          Method for accessing textual representation of the current token; if no current token (before first call to nextToken(), or after encountering end-of-input), returns null.
abstract  char[] getTextCharacters()
          Method similar to getText(), but that will return underlying (unmodifiable) character array that contains textual value, instead of constructing a String object to contain this information.
abstract  int getTextLength()
          Accessor used with getTextCharacters(), to know length of String stored in returned buffer.
abstract  int getTextOffset()
          Accessor used with getTextCharacters(), to know offset of the first text content character within buffer.
abstract  JsonLocation getTokenLocation()
          Method that return the starting location of the current token; that is, position of the first character from input that starts the current token.
 boolean hasCurrentToken()
          Method for checking whether parser currently points to a token (and data for that token is available).
abstract  boolean isClosed()
          Method that can be called to determine whether this parser is closed or not.
 boolean isEnabled(JsonParser.Feature f)
          Method for checking whether specified JsonParser.Feature is enabled.
 boolean isFeatureEnabled(JsonParser.Feature f)
          Deprecated. Use isEnabled(Feature) instead
abstract  JsonToken nextToken()
          Main iteration method, which will advance stream enough to determine type of the next token, if any.
 JsonToken nextValue()
          Iteration method that will advance stream enough to determine type of the next token that is a value type (including Json Array and Object start/end markers).
<T> T
readValueAs(Class<T> valueType)
          Method to deserialize Json content into a non-container type (it can be an array type, however): typically a bean, array or a wrapper type (like Boolean).
<T> T
readValueAs(TypeReference<?> valueTypeRef)
          Method to deserialize Json content into a Java type, reference to which is passed as argument.
 JsonNode readValueAsTree()
          Method to deserialize Json content into equivalent "tree model", represented by root JsonNode of resulting model.
abstract  void setCodec(ObjectCodec c)
          Setter that allows defining ObjectCodec associated with this parser, if any.
 void setFeature(JsonParser.Feature f, boolean state)
          Deprecated. Use configure(org.codehaus.jackson.JsonParser.Feature, boolean) instead
abstract  JsonParser skipChildren()
          Method that will skip all child tokens of an array or object token that the parser currently points to, iff stream points to JsonToken.START_OBJECT or JsonToken.START_ARRAY.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

_features

protected int _features
Bit flag composed of bits that indicate which JsonParser.Features are enabled.


_currToken

protected JsonToken _currToken
Last token retrieved via nextToken(), if any. Null before the first call to nextToken(), as well as if token has been explicitly cleared (by call to clearCurrentToken())


_lastClearedToken

protected JsonToken _lastClearedToken
Last cleared token, if any: that is, value that was in effect when clearCurrentToken() was called.

Constructor Detail

JsonParser

protected JsonParser()
Method Detail

getCodec

public abstract ObjectCodec getCodec()
Accessor for ObjectCodec associated with this parser, if any. Codec is used by readValueAs(Class) method (and its variants).

Since:
1.3

setCodec

public abstract void setCodec(ObjectCodec c)
Setter that allows defining ObjectCodec associated with this parser, if any. Codec is used by readValueAs(Class) method (and its variants).

Since:
1.3

close

public abstract void close()
                    throws IOException
Closes the parser so that no further iteration or data access can be made; will also close the underlying input source if parser either owns the input source, or feature JsonParser.Feature.AUTO_CLOSE_SOURCE is enabled. Whether parser owns the input source depends on factory method that was used to construct instance (so check JsonFactory for details, but the general idea is that if caller passes in closable resource (such as InputStream or Reader) parser does NOT own the source; but if it passes a reference (such as File or URL and creates stream or reader it does own them.

Specified by:
close in interface Closeable
Throws:
IOException

enable

public JsonParser enable(JsonParser.Feature f)
Method for enabling specified parser feature (check JsonParser.Feature for list of features)

Since:
1.2

disable

public JsonParser disable(JsonParser.Feature f)
Method for disabling specified feature (check JsonParser.Feature for list of features)

Since:
1.2

configure

public JsonParser configure(JsonParser.Feature f,
                            boolean state)
Method for enabling or disabling specified feature (check JsonParser.Feature for list of features)

Since:
1.2

isEnabled

public boolean isEnabled(JsonParser.Feature f)
Method for checking whether specified JsonParser.Feature is enabled.

Since:
1.2

setFeature

public void setFeature(JsonParser.Feature f,
                       boolean state)
Deprecated. Use configure(org.codehaus.jackson.JsonParser.Feature, boolean) instead


enableFeature

public void enableFeature(JsonParser.Feature f)
Deprecated. Use enable(Feature) instead


disableFeature

public void disableFeature(JsonParser.Feature f)
Deprecated. Use disable(Feature) instead


isFeatureEnabled

public final boolean isFeatureEnabled(JsonParser.Feature f)
Deprecated. Use isEnabled(Feature) instead


nextToken

public abstract JsonToken nextToken()
                             throws IOException,
                                    JsonParseException
Main iteration method, which will advance stream enough to determine type of the next token, if any. If none remaining (stream has no content other than possible white space before ending), null will be returned.

Returns:
Next token from the stream, if any found, or null to indicate end-of-input
Throws:
IOException
JsonParseException

nextValue

public JsonToken nextValue()
                    throws IOException,
                           JsonParseException
Iteration method that will advance stream enough to determine type of the next token that is a value type (including Json Array and Object start/end markers). Or put another way, nextToken() will be called once, and if JsonToken.FIELD_NAME is returned, another time to get the value for the field. Method is most useful for iterating over value entries of Json objects; field name will still be available by calling getCurrentName() when parser points to the value.

Returns:
Next non-field-name token from the stream, if any found, or null to indicate end-of-input (or, for non-blocking parsers, JsonToken.NOT_AVAILABLE if no tokens were available yet)
Throws:
IOException
JsonParseException
Since:
0.9.7

skipChildren

public abstract JsonParser skipChildren()
                                 throws IOException,
                                        JsonParseException
Method that will skip all child tokens of an array or object token that the parser currently points to, iff stream points to JsonToken.START_OBJECT or JsonToken.START_ARRAY. If not, it will do nothing. After skipping, stream will point to matching JsonToken.END_OBJECT or JsonToken.END_ARRAY (possibly skipping nested pairs of START/END OBJECT/ARRAY tokens as well as value tokens). The idea is that after calling this method, application will call nextToken() to point to the next available token, if any.

Throws:
IOException
JsonParseException

isClosed

public abstract boolean isClosed()
Method that can be called to determine whether this parser is closed or not. If it is closed, no new tokens can be retrieved by calling nextToken() (and the underlying stream may be closed). Closing may be due to an explicit call to close() or because parser has encountered end of input.


getCurrentToken

public JsonToken getCurrentToken()
Accessor to find which token parser currently points to, if any; null will be returned if none. If return value is non-null, data associated with the token is available via other accessor methods.

Returns:
Type of the token this parser currently points to, if any: null before any tokens have been read, and after end-of-input has been encountered, as well as if the current token has been explicitly cleared.

hasCurrentToken

public boolean hasCurrentToken()
Method for checking whether parser currently points to a token (and data for that token is available). Equivalent to check for parser.getCurrentToken() != null.

Returns:
True if the parser just returned a valid token via nextToken(); false otherwise (parser was just constructed, encountered end-of-input and returned null from nextToken(), or the token has been consumed)

clearCurrentToken

public void clearCurrentToken()
Method called to "consume" the current token by effectively removing it so that hasCurrentToken() returns false, and getCurrentToken() null). Cleared token value can still be accessed by calling getLastClearedToken() (if absolutely needed), but usually isn't.

Method was added to be used by the optional data binder, since it has to be able to consume last token used for binding (so that it will not be used again).


getCurrentName

public abstract String getCurrentName()
                               throws IOException,
                                      JsonParseException
Method that can be called to get the name associated with the current token: for JsonToken.FIELD_NAMEs it will be the same as what getText() returns; for field values it will be preceding field name; and for others (array values, root-level values) null.

Throws:
IOException
JsonParseException

getParsingContext

public abstract JsonStreamContext getParsingContext()
Method that can be used to access current parsing context reader is in. There are 3 different types: root, array and object contexts, with slightly different available information. Contexts are hierarchically nested, and can be used for example for figuring out part of the input document that correspond to specific array or object (for highlighting purposes, or error reporting). Contexts can also be used for simple xpath-like matching of input, if so desired.


getTokenLocation

public abstract JsonLocation getTokenLocation()
Method that return the starting location of the current token; that is, position of the first character from input that starts the current token.


getCurrentLocation

public abstract JsonLocation getCurrentLocation()
Method that returns location of the last processed character; usually for error reporting purposes.


getLastClearedToken

public JsonToken getLastClearedToken()
Method that can be called to get the last token that was cleared using clearCurrentToken(). This is not necessarily the latest token read. Will return null if no tokens have been cleared, or if parser has been closed.


getText

public abstract String getText()
                        throws IOException,
                               JsonParseException
Method for accessing textual representation of the current token; if no current token (before first call to nextToken(), or after encountering end-of-input), returns null. Method can be called for any token type.

Throws:
IOException
JsonParseException

getTextCharacters

public abstract char[] getTextCharacters()
                                  throws IOException,
                                         JsonParseException
Method similar to getText(), but that will return underlying (unmodifiable) character array that contains textual value, instead of constructing a String object to contain this information. Note, however, that:

Note that caller MUST NOT modify the returned character array in any way -- doing so may corrupt current parser state and render parser instance useless.

The only reason to call this method (over getText()) is to avoid construction of a String object (which will make a copy of contents).

Throws:
IOException
JsonParseException

getTextLength

public abstract int getTextLength()
                           throws IOException,
                                  JsonParseException
Accessor used with getTextCharacters(), to know length of String stored in returned buffer.

Returns:
Number of characters within buffer returned by getTextCharacters() that are part of textual content of the current token.
Throws:
IOException
JsonParseException

getTextOffset

public abstract int getTextOffset()
                           throws IOException,
                                  JsonParseException
Accessor used with getTextCharacters(), to know offset of the first text content character within buffer.

Returns:
Offset of the first character within buffer returned by getTextCharacters() that is part of textual content of the current token.
Throws:
IOException
JsonParseException

getNumberValue

public abstract Number getNumberValue()
                               throws IOException,
                                      JsonParseException
Generic number value accessor method that will work for all kinds of numeric values. It will return the optimal (simplest/smallest possibl) wrapper object that can express the numeric value just parsed.

Throws:
IOException
JsonParseException

getNumberType

public abstract JsonParser.NumberType getNumberType()
                                             throws IOException,
                                                    JsonParseException
If current token is of type JsonToken.VALUE_NUMBER_INT or JsonToken.VALUE_NUMBER_FLOAT, returns one of JsonParser.NumberType constants; otherwise returns null.

Throws:
IOException
JsonParseException

getByteValue

public byte getByteValue()
                  throws IOException,
                         JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java byte primitive type. It can also be called for JsonToken.VALUE_NUMBER_FLOAT; if so, it is equivalent to calling getDoubleValue() and then casting; except for possible overflow/underflow exception.

Note: if the resulting integer value falls outside range of Java byte, a JsonParseException will be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getShortValue

public short getShortValue()
                    throws IOException,
                           JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java short primitive type. It can also be called for JsonToken.VALUE_NUMBER_FLOAT; if so, it is equivalent to calling getDoubleValue() and then casting; except for possible overflow/underflow exception.

Note: if the resulting integer value falls outside range of Java short, a JsonParseException will be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getIntValue

public abstract int getIntValue()
                         throws IOException,
                                JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a value of Java int primitive type. It can also be called for JsonToken.VALUE_NUMBER_FLOAT; if so, it is equivalent to calling getDoubleValue() and then casting; except for possible overflow/underflow exception.

Note: if the resulting integer value falls outside range of Java int, a JsonParseException may be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getLongValue

public abstract long getLongValue()
                           throws IOException,
                                  JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can be expressed as a Java long primitive type. It can also be called for JsonToken.VALUE_NUMBER_FLOAT; if so, it is equivalent to calling getDoubleValue() and then casting to int; except for possible overflow/underflow exception.

Note: if the token is an integer, but its value falls outside of range of Java long, a JsonParseException may be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getBigIntegerValue

public abstract BigInteger getBigIntegerValue()
                                       throws IOException,
                                              JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_INT and it can not be used as a Java long primitive type due to its magnitude. It can also be called for JsonToken.VALUE_NUMBER_FLOAT; if so, it is equivalent to calling getDecimalValue() and then constructing a BigInteger from that value.

Throws:
IOException
JsonParseException

getFloatValue

public abstract float getFloatValue()
                             throws IOException,
                                    JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT and it can be expressed as a Java float primitive type. It can also be called for JsonToken.VALUE_NUMBER_INT; if so, it is equivalent to calling getLongValue() and then casting; except for possible overflow/underflow exception.

Note: if the value falls outside of range of Java float, a JsonParseException will be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getDoubleValue

public abstract double getDoubleValue()
                               throws IOException,
                                      JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT and it can be expressed as a Java double primitive type. It can also be called for JsonToken.VALUE_NUMBER_INT; if so, it is equivalent to calling getLongValue() and then casting; except for possible overflow/underflow exception.

Note: if the value falls outside of range of Java double, a JsonParseException will be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException

getDecimalValue

public abstract BigDecimal getDecimalValue()
                                    throws IOException,
                                           JsonParseException
Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT or JsonToken.VALUE_NUMBER_INT. No under/overflow exceptions are ever thrown.

Throws:
IOException
JsonParseException

getBooleanValue

public boolean getBooleanValue()
                        throws IOException,
                               JsonParseException
Convenience accessor that can be called when the current token is JsonToken.VALUE_TRUE or JsonToken.VALUE_FALSE.

Note: if the token is not of above-mentioned boolean types, an integer, but its value falls outside of range of Java long, a JsonParseException may be thrown to indicate numeric overflow/underflow.

Throws:
IOException
JsonParseException
Since:
1.3

getEmbeddedObject

public Object getEmbeddedObject()
                         throws IOException,
                                JsonParseException
Accessor that can be called if (and only if) the current token is JsonToken.VALUE_EMBEDDED_OBJECT. For other token types, null is returned.

Note: only some specialized parser implementations support embedding of objects (usually ones that are facades on top of non-streaming sources, such as object trees).

Throws:
IOException
JsonParseException
Since:
1.3

getBinaryValue

public abstract byte[] getBinaryValue(Base64Variant b64variant)
                               throws IOException,
                                      JsonParseException
Method that can be used to read (and consume -- results may not be accessible using other methods after the call) base64-encoded binary data included in the current textual json value. It works similar to getting String value via getText() and decoding result (except for decoding part), but should be significantly more performant.

Note that non-decoded textual contents of the current token are not guaranteed to be accessible after this method is called. Current implementation, for example, clears up textual content during decoding. Decoded binary content, however, will be retained until parser is advanced to the next event.

Parameters:
b64variant - Expected variant of base64 encoded content (see Base64Variants for definitions of "standard" variants).
Returns:
Decoded binary data
Throws:
IOException
JsonParseException

getBinaryValue

public byte[] getBinaryValue()
                      throws IOException,
                             JsonParseException
Convenience alternative to getBinaryValue(Base64Variant) that defaults to using Base64Variants.getDefaultVariant() as the default encoding.

Throws:
IOException
JsonParseException

readValueAs

public <T> T readValueAs(Class<T> valueType)
              throws IOException,
                     JsonProcessingException
Method to deserialize Json content into a non-container type (it can be an array type, however): typically a bean, array or a wrapper type (like Boolean). Note: method can only be called if the parser has an object codec assigned; this is true for parsers constructed by MappingJsonFactory but not for JsonFactory (unless its setCodec method has been explicitly called).

This method may advance the event stream, for structured types the current token will be the closing end marker (END_ARRAY, END_OBJECT) of the bound structure. For non-structured Json types (and for JsonToken.VALUE_EMBEDDED_OBJECT) stream is not advanced.

Note: this method should NOT be used if the result type is a container (Collection or Map. The reason is that due to type erasure, key and value types can not be introspected when using this method.

Throws:
IOException
JsonProcessingException

readValueAs

public <T> T readValueAs(TypeReference<?> valueTypeRef)
              throws IOException,
                     JsonProcessingException
Method to deserialize Json content into a Java type, reference to which is passed as argument. Type is passed using so-called "super type token" and specifically needs to be used if the root type is a parameterized (generic) container type. Note: method can only be called if the parser has an object codec assigned; this is true for parsers constructed by MappingJsonFactory but not for JsonFactory (unless its setCodec method has been explicitly called).

This method may advance the event stream, for structured types the current token will be the closing end marker (END_ARRAY, END_OBJECT) of the bound structure. For non-structured Json types (and for JsonToken.VALUE_EMBEDDED_OBJECT) stream is not advanced.

Throws:
IOException
JsonProcessingException

readValueAsTree

public JsonNode readValueAsTree()
                         throws IOException,
                                JsonProcessingException
Method to deserialize Json content into equivalent "tree model", represented by root JsonNode of resulting model. For Json Arrays it will an array node (with child nodes), for objects object node (with child nodes), and for other types matching leaf node type

Throws:
IOException
JsonProcessingException

_constructError

protected JsonParseException _constructError(String msg)
Helper method for constructing JsonParseExceptions based on current state of the parser