JsonWriter (Moshi 1.4.0 API)

java.lang.Object
- com.squareup.moshi.JsonWriter

All Implemented Interfaces:: Closeable, Flushable, AutoCloseable

public abstract class JsonWriter
extends Object
implements Closeable, Flushable

Writes a JSON (RFC 7159) encoded value to a stream, one token at a time. The stream includes both literal values (strings, numbers, booleans and nulls) as well as the begin and end delimiters of objects and arrays.

Encoding JSON

To encode your data as JSON, create a new JsonWriter. Each JSON document must contain one top-level array or object. Call methods on the writer as you walk the structure's contents, nesting arrays and objects as necessary:

To write arrays, first call beginArray(). Write each of the array's elements with the appropriate value(java.lang.String) methods or by nesting other arrays and objects. Finally close the array using endArray().
To write objects, first call beginObject(). Write each of the object's properties by alternating calls to name(java.lang.String) with the property's value. Write property values with the appropriate value(java.lang.String) method or by nesting other objects or arrays. Finally close the object using endObject().

Example

Suppose we'd like to encode a stream of messages such as the following:

 
 [
   {
     "id": 912345678901,
     "text": "How do I stream JSON in Java?",
     "geo": null,
     "user": {
       "name": "json_newb",
       "followers_count": 41
      }
   },
   {
     "id": 912345678902,
     "text": "@json_newb just use JsonWriter!",
     "geo": [50.454722, -104.606667],
     "user": {
       "name": "jesse",
       "followers_count": 2
     }
   }
 ]

This code encodes the above structure:

   
   public void writeJsonStream(BufferedSink sink, List<Message> messages) throws IOException {
     JsonWriter writer = JsonWriter.of(sink);
     writer.setIndent("  ");
     writeMessagesArray(writer, messages);
     writer.close();
   }

   public void writeMessagesArray(JsonWriter writer, List<Message> messages) throws IOException {
     writer.beginArray();
     for (Message message : messages) {
       writeMessage(writer, message);
     }
     writer.endArray();
   }

   public void writeMessage(JsonWriter writer, Message message) throws IOException {
     writer.beginObject();
     writer.name("id").value(message.getId());
     writer.name("text").value(message.getText());
     if (message.getGeo() != null) {
       writer.name("geo");
       writeDoublesArray(writer, message.getGeo());
     } else {
       writer.name("geo").nullValue();
     }
     writer.name("user");
     writeUser(writer, message.getUser());
     writer.endObject();
   }

   public void writeUser(JsonWriter writer, User user) throws IOException {
     writer.beginObject();
     writer.name("name").value(user.getName());
     writer.name("followers_count").value(user.getFollowersCount());
     writer.endObject();
   }

   public void writeDoublesArray(JsonWriter writer, List<Double> doubles) throws IOException {
     writer.beginArray();
     for (Double value : doubles) {
       writer.value(value);
     }
     writer.endArray();
   }

Each JsonWriter may be used to write a single JSON stream. Instances of this class are not thread safe. Calls that would result in a malformed JSON string will fail with an IllegalStateException.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract JsonWriter`	`beginArray()` Begins encoding a new array.
`abstract JsonWriter`	`beginObject()` Begins encoding a new object.
`abstract JsonWriter`	`endArray()` Ends encoding the current array.
`abstract JsonWriter`	`endObject()` Ends encoding the current object.
`String`	`getIndent()` Returns a string containing only whitespace, used for each level of indentation.
`String`	`getPath()` Returns a JsonPath to the current location in the JSON value.
`boolean`	`getSerializeNulls()` Returns true if object members are serialized when their value is null.
`boolean`	`isLenient()` Returns true if this writer has relaxed syntax rules.
`abstract JsonWriter`	`name(String name)` Encodes the property name.
`abstract JsonWriter`	`nullValue()` Encodes `null`.
`static JsonWriter`	`of(okio.BufferedSink sink)` Returns a new instance that writes UTF-8 encoded JSON to `sink`.
`void`	`setIndent(String indent)` Sets the indentation string to be repeated for each level of indentation in the encoded document.
`void`	`setLenient(boolean lenient)` Configure this writer to relax its syntax rules.
`void`	`setSerializeNulls(boolean serializeNulls)` Sets whether object members are serialized when their value is null.
`abstract JsonWriter`	`value(boolean value)` Encodes `value`.
`abstract JsonWriter`	`value(Boolean value)` Encodes `value`.
`abstract JsonWriter`	`value(double value)` Encodes `value`.
`abstract JsonWriter`	`value(long value)` Encodes `value`.
`abstract JsonWriter`	`value(Number value)` Encodes `value`.
`abstract JsonWriter`	`value(String value)` Encodes `value`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.io.Closeable
close

Methods inherited from interface java.io.Flushable
flush

- Method Detail
  - of
```
public static JsonWriter of(okio.BufferedSink sink)
```
    Returns a new instance that writes UTF-8 encoded JSON to sink.
  - setIndent
```
public void setIndent(String indent)
```
    Sets the indentation string to be repeated for each level of indentation in the encoded document. If indent.isEmpty() the encoded document will be compact. Otherwise the encoded document will be more human-readable.
    
    Parameters:
    
    indent - a string containing only whitespace.
  - getIndent
```
public final String getIndent()
```
    Returns a string containing only whitespace, used for each level of indentation. If empty, the encoded document will be compact.
  - setLenient
```
public final void setLenient(boolean lenient)
```
    Configure this writer to relax its syntax rules. By default, this writer only emits well-formed JSON as specified by RFC 7159. Setting the writer to lenient permits the following:
    - Top-level values of any type. With strict writing, the top-level value must be an object or an array.
    - Numbers may be NaNs or infinities.
  - isLenient
```
public final boolean isLenient()
```
    Returns true if this writer has relaxed syntax rules.
  - setSerializeNulls
```
public final void setSerializeNulls(boolean serializeNulls)
```
    Sets whether object members are serialized when their value is null. This has no impact on array elements. The default is false.
  - getSerializeNulls
```
public final boolean getSerializeNulls()
```
    Returns true if object members are serialized when their value is null. This has no impact on array elements. The default is false.
  - beginArray
```
public abstract JsonWriter beginArray()
                               throws IOException
```
    Begins encoding a new array. Each call to this method must be paired with a call to endArray().
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - endArray
```
public abstract JsonWriter endArray()
                             throws IOException
```
    Ends encoding the current array.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - beginObject
```
public abstract JsonWriter beginObject()
                                throws IOException
```
    Begins encoding a new object. Each call to this method must be paired with a call to endObject().
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - endObject
```
public abstract JsonWriter endObject()
                              throws IOException
```
    Ends encoding the current object.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - name
```
public abstract JsonWriter name(String name)
                         throws IOException
```
    Encodes the property name.
    
    Parameters:
    
    name - the name of the forthcoming value. May not be null.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(String value)
                          throws IOException
```
    Encodes value.
    
    Parameters:
    
    value - the literal string value, or null to encode a null literal.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - nullValue
```
public abstract JsonWriter nullValue()
                              throws IOException
```
    Encodes null.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(boolean value)
                          throws IOException
```
    Encodes value.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(Boolean value)
                          throws IOException
```
    Encodes value.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(double value)
                          throws IOException
```
    Encodes value.
    
    Parameters:
    
    value - a finite value. May not be NaNs or infinities.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(long value)
                          throws IOException
```
    Encodes value.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - value
```
public abstract JsonWriter value(Number value)
                          throws IOException
```
    Encodes value.
    
    Parameters:
    
    value - a finite value. May not be NaNs or infinities.
    
    Returns:
    
    this writer.
    
    Throws:
    
    IOException
  - getPath
```
public final String getPath()
```
    Returns a JsonPath to the current location in the JSON value.

Class JsonWriter

Encoding JSON

Example

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.io.Closeable

Methods inherited from interface java.io.Flushable

Method Detail

of

setIndent

getIndent

setLenient

isLenient

setSerializeNulls

getSerializeNulls

beginArray

endArray

beginObject

endObject

name

value

nullValue

value

value

value

value

value

getPath