JsonToken.java
/* Jackson JSON-processor.
*
* Copyright (c) 2007- Tatu Saloranta, tatu.saloranta@iki.fi
*/
package com.fasterxml.jackson.core;
/**
* Enumeration for basic token types used for returning results
* of parsing JSON content.
*/
public enum JsonToken
{
/* Some notes on implementation:
*
* - Entries are to be ordered such that start/end array/object
* markers come first, then field name marker (if any), and
* finally scalar value tokens. This is assumed by some
* typing checks.
*/
/**
* NOT_AVAILABLE can be returned if {@link JsonParser}
* implementation cannot currently return the requested
* token (usually next one), or even if any will be
* available, but that may be able to determine this in
* future. This is the case with non-blocking parsers --
* they cannot block to wait for more data to parse and
* must return something.
*/
NOT_AVAILABLE(null, JsonTokenId.ID_NOT_AVAILABLE),
/**
* START_OBJECT is returned when encountering '{'
* which signals starting of an Object value.
*/
START_OBJECT("{", JsonTokenId.ID_START_OBJECT),
/**
* END_OBJECT is returned when encountering '}'
* which signals ending of an Object value
*/
END_OBJECT("}", JsonTokenId.ID_END_OBJECT),
/**
* START_ARRAY is returned when encountering '['
* which signals starting of an Array value
*/
START_ARRAY("[", JsonTokenId.ID_START_ARRAY),
/**
* END_ARRAY is returned when encountering ']'
* which signals ending of an Array value
*/
END_ARRAY("]", JsonTokenId.ID_END_ARRAY),
/**
* FIELD_NAME is returned when a String token is encountered
* as a field name (same lexical value, different function).
*<p>
* NOTE: in Jackson 3.x this enum is renamed as {@code PROPERTY_NAME}
*/
FIELD_NAME(null, JsonTokenId.ID_FIELD_NAME),
/**
* Placeholder token returned when the input source has a concept
* of embedded Object that are not accessible as usual structure
* (of starting with {@link #START_OBJECT}, having values, ending with
* {@link #END_OBJECT}), but as "raw" objects.
*<p>
* Note: this token is never returned by regular JSON readers, but
* only by readers that expose other kinds of source (like
* <code>JsonNode</code>-based JSON trees, Maps, Lists and such).
*/
VALUE_EMBEDDED_OBJECT(null, JsonTokenId.ID_EMBEDDED_OBJECT),
/**
* VALUE_STRING is returned when a String token is encountered
* in value context (array element, field value, or root-level
* stand-alone value)
*/
VALUE_STRING(null, JsonTokenId.ID_STRING),
/**
* VALUE_NUMBER_INT is returned when an integer numeric token is
* encountered in value context: that is, a number that does
* not have floating point or exponent marker in it (consists
* only of an optional sign, followed by one or more digits;
* or, for binary formats, is indicated as integral number
* by internal representation).
*/
VALUE_NUMBER_INT(null, JsonTokenId.ID_NUMBER_INT),
/**
* VALUE_NUMBER_FLOAT is returned when a numeric token other
* than integer is encountered: that is, a number that does
* have floating point or exponent marker in it, in addition
* to one or more digits (or, for non-textual formats,
* has internal floating-point representation).
*/
VALUE_NUMBER_FLOAT(null, JsonTokenId.ID_NUMBER_FLOAT),
/**
* VALUE_TRUE is returned when encountering literal "true" in
* value context
*/
VALUE_TRUE("true", JsonTokenId.ID_TRUE),
/**
* VALUE_FALSE is returned when encountering literal "false" in
* value context
*/
VALUE_FALSE("false", JsonTokenId.ID_FALSE),
/**
* VALUE_NULL is returned when encountering literal "null" in
* value context
*/
VALUE_NULL("null", JsonTokenId.ID_NULL),
;
final String _serialized;
final char[] _serializedChars;
final byte[] _serializedBytes;
final int _id;
final boolean _isStructStart, _isStructEnd;
final boolean _isNumber;
final boolean _isBoolean;
final boolean _isScalar;
/**
* @param token representation for this token, if there is a
* single static representation; null otherwise
* @param id Numeric id from {@link JsonTokenId}
*/
JsonToken(String token, int id)
{
if (token == null) {
_serialized = null;
_serializedChars = null;
_serializedBytes = null;
} else {
_serialized = token;
_serializedChars = token.toCharArray();
// It's all in ascii, can just case...
int len = _serializedChars.length;
_serializedBytes = new byte[len];
for (int i = 0; i < len; ++i) {
_serializedBytes[i] = (byte) _serializedChars[i];
}
}
_id = id;
_isBoolean = (id == JsonTokenId.ID_FALSE || id == JsonTokenId.ID_TRUE);
_isNumber = (id == JsonTokenId.ID_NUMBER_INT || id == JsonTokenId.ID_NUMBER_FLOAT);
_isStructStart = (id == JsonTokenId.ID_START_OBJECT || id == JsonTokenId.ID_START_ARRAY);
_isStructEnd = (id == JsonTokenId.ID_END_OBJECT || id == JsonTokenId.ID_END_ARRAY);
_isScalar = !_isStructStart && !_isStructEnd
&& (id != JsonTokenId.ID_FIELD_NAME)
&& (id != JsonTokenId.ID_NOT_AVAILABLE);
}
public final int id() { return _id; }
public final String asString() { return _serialized; }
public final char[] asCharArray() { return _serializedChars; }
public final byte[] asByteArray() { return _serializedBytes; }
/**
* @return {@code True} if this token is {@code VALUE_NUMBER_INT} or {@code VALUE_NUMBER_FLOAT},
* {@code false} otherwise
*/
public final boolean isNumeric() { return _isNumber; }
/**
* Accessor that is functionally equivalent to:
* <code>
* this == JsonToken.START_OBJECT || this == JsonToken.START_ARRAY
* </code>
*
* @return {@code True} if this token is {@code START_OBJECT} or {@code START_ARRAY},
* {@code false} otherwise
*
* @since 2.3
*/
public final boolean isStructStart() { return _isStructStart; }
/**
* Accessor that is functionally equivalent to:
* <code>
* this == JsonToken.END_OBJECT || this == JsonToken.END_ARRAY
* </code>
*
* @return {@code True} if this token is {@code END_OBJECT} or {@code END_ARRAY},
* {@code false} otherwise
*
* @since 2.3
*/
public final boolean isStructEnd() { return _isStructEnd; }
/**
* Method that can be used to check whether this token represents
* a valid non-structured value. This means all {@code VALUE_xxx} tokens;
* excluding {@code START_xxx} and {@code END_xxx} tokens as well
* {@code FIELD_NAME}.
*
* @return {@code True} if this token is a scalar value token (one of
* {@code VALUE_xxx} tokens), {@code false} otherwise
*/
public final boolean isScalarValue() { return _isScalar; }
/**
* @return {@code True} if this token is {@code VALUE_TRUE} or {@code VALUE_FALSE},
* {@code false} otherwise
*/
public final boolean isBoolean() { return _isBoolean; }
/**
* Helper method for constructing description like "Object value" given
* {@link JsonToken} encountered.
*
* @param t Token to get description for
*
* @return String description of given token
*
* @since 2.16
*/
public static String valueDescFor(JsonToken t) {
if (t == null) {
return "<end of input>";
}
switch (t) {
case START_OBJECT:
case END_OBJECT:
case FIELD_NAME:
return "Object value";
case START_ARRAY:
case END_ARRAY:
return "Array value";
case VALUE_FALSE:
case VALUE_TRUE:
return "Boolean value";
case VALUE_EMBEDDED_OBJECT:
return "Embedded Object value";
case VALUE_NUMBER_FLOAT:
return "Floating-point value";
case VALUE_NUMBER_INT:
return "Integer value";
case VALUE_STRING:
return "String value";
case VALUE_NULL:
return "Null value";
case NOT_AVAILABLE:
default:
return "[Unavailable value]";
}
}
}