JsonProcessor<Reader extends JsonReader> class abstract base

A generalized JSON processor.

The processor traverses JSON-like data as provided by a JsonReader. It dispatches to individual process methods for each kind of JSON value, but doesn't process the value by default. These methods can be overridden in subclasses to do something useful. For example, the JsonSinkProcessor defaults to forwarding each kind of JSON data to a JsonSink.

The processor is similar to a JsonSink in that there are methods for each kind of JSON data, but instead of passing the JSON values to the individual add methods, the process methods of the processsor takes a reader which is ready to provide the value.

The process-method can either read the value, skip it, or even read the source using JsonReader.expectAnyValueSource and handle it itself.

Each process-method takes a key which is non-null when the value is a JSON-object value. This allows the processor to easily skip entire entries, perhaps even based on the key name.

An example implementation of processNum could be:

  void processNum(JsonReader reader, String? key) {
    if (key != null && key.startsWith("x-")) {
      // Ignore key and value.
      reader.skipAnyValue();
    } else {
      // Add key and value to a JsonSink.
      if (key != null) sink.addKey(key);
      sink.addNumber(reader.expectNum());
    }
  }

Implementers

• JsonSinkProcessor

Constructors

JsonProcessor()

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

endArray(String? key) → void

Called when an array has no more elements.

endObject(String? key) → void

Called after all key/value pairs of the current object are processed.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

processArray(Reader reader, String? key) → bool

Called when the reader encounters a JSON array.

processBool(Reader reader, String? key) → void

Called when the next value is a boolean value.

processNull(Reader reader, String? key) → void

Called when the next value is a null value.

processNum(Reader reader, String? key) → void

Called when the next value is a number value.

processObject(Reader reader, String? key) → bool

Called when the reader encounters the start of a JSON object.

processObjectEntry(Reader reader) → void

Called for each JSON object entry.

processString(Reader reader, String? key) → void

Called when the next value is a string value.

processUnknown(Reader reader, String? key) → void

Invoked for a reader which has no value or an unrecognized value.

processValue(Reader reader, [String? key]) → void

Process a JSON-value.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited