org.codehaus.jackson.node
Class TreeTraversingParser

java.lang.Object
  extended by org.codehaus.jackson.JsonParser
      extended by org.codehaus.jackson.impl.JsonParserMinimalBase
          extended by org.codehaus.jackson.node.TreeTraversingParser
All Implemented Interfaces:
Closeable, Versioned

public class TreeTraversingParser
extends JsonParserMinimalBase

Facade over JsonNode that implements JsonParser to allow accessing contents of JSON tree in alternate form (stream of tokens). Useful when a streaming source is expected by code, such as data binding functionality.

Since:
1.3
Author:
tatu

Nested Class Summary
 
Nested classes/interfaces inherited from class org.codehaus.jackson.JsonParser
JsonParser.Feature, JsonParser.NumberType
 
Field Summary
protected  boolean _closed
          Flag that indicates whether parser is closed or not.
protected  JsonToken _nextToken
          Sometimes parser needs to buffer a single look-ahead token; if so, it'll be stored here.
protected  org.codehaus.jackson.node.NodeCursor _nodeCursor
          Traversal context within tree
protected  ObjectCodec _objectCodec
           
protected  boolean _startContainer
          Flag needed to handle recursion into contents of child Array/Object nodes.
 
Fields inherited from class org.codehaus.jackson.impl.JsonParserMinimalBase
INT_APOSTROPHE, INT_ASTERISK, INT_b, INT_BACKSLASH, INT_COLON, INT_COMMA, INT_CR, INT_f, INT_LBRACKET, INT_LCURLY, INT_LF, INT_n, INT_QUOTE, INT_r, INT_RBRACKET, INT_RCURLY, INT_SLASH, INT_SPACE, INT_t, INT_TAB, INT_u
 
Fields inherited from class org.codehaus.jackson.JsonParser
_currToken, _features, _lastClearedToken
 
Constructor Summary
TreeTraversingParser(JsonNode n)
           
TreeTraversingParser(JsonNode n, ObjectCodec codec)
           
 
Method Summary
protected  void _handleEOF()
          Method sub-classes need to implement
 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.
protected  JsonNode currentNode()
           
protected  JsonNode currentNumericNode()
           
 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(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.
 ObjectCodec getCodec()
          Accessor for ObjectCodec associated with this parser, if any.
 JsonLocation getCurrentLocation()
          Method that returns location of the last processed character; usually for error reporting purposes.
 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 JsonParser.getText() returns; for field values it will be preceding field name; and for others (array values, root-level values) null.
 BigDecimal getDecimalValue()
          Numeric accessor that can be called when the current token is of type JsonToken.VALUE_NUMBER_FLOAT or JsonToken.VALUE_NUMBER_INT.
 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.
 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.
 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.
 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.
 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.
 Number getNumberValue()
          Generic number value accessor method that will work for all kinds of numeric values.
 JsonStreamContext getParsingContext()
          Method that can be used to access current parsing context reader is in.
 String getText()
          Method for accessing textual representation of the current token; if no current token (before first call to JsonParser.nextToken(), or after encountering end-of-input), returns null.
 char[] getTextCharacters()
          Method similar to JsonParser.getText(), but that will return underlying (unmodifiable) character array that contains textual value, instead of constructing a String object to contain this information.
 int getTextLength()
          Accessor used with JsonParser.getTextCharacters(), to know length of String stored in returned buffer.
 int getTextOffset()
          Accessor used with JsonParser.getTextCharacters(), to know offset of the first text content character within buffer.
 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 hasTextCharacters()
          Method that can be used to determine whether calling of JsonParser.getTextCharacters() would be the most efficient way to access textual content for the event parser currently points to.
 boolean isClosed()
          Method that can be called to determine whether this parser is closed or not.
 JsonToken nextToken()
          Main iteration method, which will advance stream enough to determine type of the next token, if any.
 void setCodec(ObjectCodec c)
          Setter that allows defining ObjectCodec associated with this parser, if any.
 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 org.codehaus.jackson.impl.JsonParserMinimalBase
_constructError, _getCharDesc, _handleUnrecognizedCharacterEscape, _reportError, _reportInvalidEOF, _reportInvalidEOF, _reportUnexpectedChar, _throwInternal, _throwInvalidSpace, _throwUnquotedSpace, _wrapError, getValueAsDouble, getValueAsInt, getValueAsLong
 
Methods inherited from class org.codehaus.jackson.JsonParser
_constructError, clearCurrentToken, configure, disable, disableFeature, enable, enableFeature, getBinaryValue, getBooleanValue, getByteValue, getCurrentToken, getLastClearedToken, getShortValue, getValueAsDouble, getValueAsInt, getValueAsLong, hasCurrentToken, isEnabled, isFeatureEnabled, nextValue, readValueAs, readValueAs, readValueAsTree, releaseBuffered, releaseBuffered, setFeature, version
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

_objectCodec

protected ObjectCodec _objectCodec

_nodeCursor

protected org.codehaus.jackson.node.NodeCursor _nodeCursor
Traversal context within tree


_nextToken

protected JsonToken _nextToken
Sometimes parser needs to buffer a single look-ahead token; if so, it'll be stored here. This is currently used for handling


_startContainer

protected boolean _startContainer
Flag needed to handle recursion into contents of child Array/Object nodes.


_closed

protected boolean _closed
Flag that indicates whether parser is closed or not. Gets set when parser is either closed by explicit call (close()) or when end-of-input is reached.

Constructor Detail

TreeTraversingParser

public TreeTraversingParser(JsonNode n)

TreeTraversingParser

public TreeTraversingParser(JsonNode n,
                            ObjectCodec codec)
Method Detail

setCodec

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

Specified by:
setCodec in class JsonParser

getCodec

public ObjectCodec getCodec()
Description copied from class: JsonParser
Accessor for ObjectCodec associated with this parser, if any. Codec is used by JsonParser.readValueAs(Class) method (and its variants).

Specified by:
getCodec in class JsonParser

close

public void close()
           throws IOException
Description copied from class: JsonParser
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
Specified by:
close in class JsonParserMinimalBase
Throws:
IOException

nextToken

public JsonToken nextToken()
                    throws IOException,
                           JsonParseException
Description copied from class: JsonParser
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.

Specified by:
nextToken in class JsonParserMinimalBase
Returns:
Next token from the stream, if any found, or null to indicate end-of-input
Throws:
IOException
JsonParseException

skipChildren

public JsonParser skipChildren()
                        throws IOException,
                               JsonParseException
Description copied from class: JsonParser
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 JsonParser.nextToken() to point to the next available token, if any.

Overrides:
skipChildren in class JsonParserMinimalBase
Throws:
IOException
JsonParseException

isClosed

public boolean isClosed()
Description copied from class: JsonParser
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 JsonParser.nextToken() (and the underlying stream may be closed). Closing may be due to an explicit call to JsonParser.close() or because parser has encountered end of input.

Specified by:
isClosed in class JsonParserMinimalBase

getCurrentName

public String getCurrentName()
Description copied from class: JsonParser
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 JsonParser.getText() returns; for field values it will be preceding field name; and for others (array values, root-level values) null.

Specified by:
getCurrentName in class JsonParserMinimalBase

getParsingContext

public JsonStreamContext getParsingContext()
Description copied from class: JsonParser
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.

Specified by:
getParsingContext in class JsonParserMinimalBase

getTokenLocation

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

Specified by:
getTokenLocation in class JsonParser

getCurrentLocation

public JsonLocation getCurrentLocation()
Description copied from class: JsonParser
Method that returns location of the last processed character; usually for error reporting purposes.

Specified by:
getCurrentLocation in class JsonParser

getText

public String getText()
Description copied from class: JsonParser
Method for accessing textual representation of the current token; if no current token (before first call to JsonParser.nextToken(), or after encountering end-of-input), returns null. Method can be called for any token type.

Specified by:
getText in class JsonParserMinimalBase

getTextCharacters

public char[] getTextCharacters()
                         throws IOException,
                                JsonParseException
Description copied from class: JsonParser
Method similar to JsonParser.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 JsonParser.getText()) is to avoid construction of a String object (which will make a copy of contents).

Specified by:
getTextCharacters in class JsonParserMinimalBase
Throws:
IOException
JsonParseException

getTextLength

public int getTextLength()
                  throws IOException,
                         JsonParseException
Description copied from class: JsonParser
Accessor used with JsonParser.getTextCharacters(), to know length of String stored in returned buffer.

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

getTextOffset

public int getTextOffset()
                  throws IOException,
                         JsonParseException
Description copied from class: JsonParser
Accessor used with JsonParser.getTextCharacters(), to know offset of the first text content character within buffer.

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

hasTextCharacters

public boolean hasTextCharacters()
Description copied from class: JsonParser
Method that can be used to determine whether calling of JsonParser.getTextCharacters() would be the most efficient way to access textual content for the event parser currently points to.

Default implementation simply returns false since only actual implementation class has knowledge of its internal buffering state. Implementations are strongly encouraged to properly override this method, to allow efficient copying of content by other code.

Specified by:
hasTextCharacters in class JsonParserMinimalBase
Returns:
True if parser currently has character array that can be efficiently returned via JsonParser.getTextCharacters(); false means that it may or may not exist

getNumberType

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

Specified by:
getNumberType in class JsonParser
Throws:
IOException
JsonParseException

getBigIntegerValue

public BigInteger getBigIntegerValue()
                              throws IOException,
                                     JsonParseException
Description copied from class: JsonParser
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 JsonParser.getDecimalValue() and then constructing a BigInteger from that value.

Specified by:
getBigIntegerValue in class JsonParser
Throws:
IOException
JsonParseException

getDecimalValue

public BigDecimal getDecimalValue()
                           throws IOException,
                                  JsonParseException
Description copied from class: JsonParser
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.

Specified by:
getDecimalValue in class JsonParser
Throws:
IOException
JsonParseException

getDoubleValue

public double getDoubleValue()
                      throws IOException,
                             JsonParseException
Description copied from class: JsonParser
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 JsonParser.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.

Specified by:
getDoubleValue in class JsonParser
Throws:
IOException
JsonParseException

getFloatValue

public float getFloatValue()
                    throws IOException,
                           JsonParseException
Description copied from class: JsonParser
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 JsonParser.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.

Specified by:
getFloatValue in class JsonParser
Throws:
IOException
JsonParseException

getLongValue

public long getLongValue()
                  throws IOException,
                         JsonParseException
Description copied from class: JsonParser
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 JsonParser.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.

Specified by:
getLongValue in class JsonParser
Throws:
IOException
JsonParseException

getIntValue

public int getIntValue()
                throws IOException,
                       JsonParseException
Description copied from class: JsonParser
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 JsonParser.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.

Specified by:
getIntValue in class JsonParser
Throws:
IOException
JsonParseException

getNumberValue

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

Specified by:
getNumberValue in class JsonParser
Throws:
IOException
JsonParseException

getEmbeddedObject

public Object getEmbeddedObject()
Description copied from class: JsonParser
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).

Overrides:
getEmbeddedObject in class JsonParser

getBinaryValue

public byte[] getBinaryValue(Base64Variant b64variant)
                      throws IOException,
                             JsonParseException
Description copied from class: JsonParser
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 JsonParser.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.

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

currentNode

protected JsonNode currentNode()

currentNumericNode

protected JsonNode currentNumericNode()
                               throws JsonParseException
Throws:
JsonParseException

_handleEOF

protected void _handleEOF()
                   throws JsonParseException
Description copied from class: JsonParserMinimalBase
Method sub-classes need to implement

Specified by:
_handleEOF in class JsonParserMinimalBase
Throws:
JsonParseException