JsonDecoder (Apache Avro Java 1.9.2 API)

java.lang.Object
- org.apache.avro.io.Decoder
- - org.apache.avro.io.ParsingDecoder
  - - org.apache.avro.io.JsonDecoder

All Implemented Interfaces:

Parser.ActionHandler, SkipParser.SkipHandler
```
public class JsonDecoder
extends ParsingDecoder
implements Parser.ActionHandler
```
A Decoder for Avro's JSON data encoding.
Construct using DecoderFactory.
JsonDecoder is not thread-safe.

Field Summary
- Fields inherited from class org.apache.avro.io.ParsingDecoder
  parser

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`long`	`arrayNext()` Processes the next block of an array and returns the number of items in the block and let's the caller read those items.
`JsonDecoder`	`configure(InputStream in)` Reconfigures this JsonDecoder to use the InputStream provided.
`JsonDecoder`	`configure(String in)` Reconfigures this JsonDecoder to use the String provided for input.
`Symbol`	`doAction(Symbol input, Symbol top)` Handle the action symbol `top` when the `input` is sought to be taken off the stack.
`long`	`mapNext()` Processes the next block of map entries and returns the count of them.
`long`	`readArrayStart()` Reads and returns the size of the first block of an array.
`boolean`	`readBoolean()` Reads a boolean value written by `Encoder.writeBoolean(boolean)`.
`ByteBuffer`	`readBytes(ByteBuffer old)` Reads a byte-string written by `Encoder.writeBytes(java.nio.ByteBuffer)`.
`double`	`readDouble()` Reads a double written by `Encoder.writeDouble(double)`.
`int`	`readEnum()` Reads an enumeration.
`void`	`readFixed(byte[] bytes, int start, int len)` Reads fixed sized binary object.
`float`	`readFloat()` Reads a float written by `Encoder.writeFloat(float)`.
`int`	`readIndex()` Reads the tag of a union written by `Encoder.writeIndex(int)`.
`int`	`readInt()` Reads an integer written by `Encoder.writeInt(int)`.
`long`	`readLong()` Reads a long written by `Encoder.writeLong(long)`.
`long`	`readMapStart()` Reads and returns the size of the next block of map-entries.
`void`	`readNull()` "Reads" a null value.
`String`	`readString()` Reads a char-string written by `Encoder.writeString(org.apache.avro.util.Utf8)`.
`Utf8`	`readString(Utf8 old)` Reads a char-string written by `Encoder.writeString(org.apache.avro.util.Utf8)`.
`long`	`skipArray()` Used for quickly skipping through an array.
`void`	`skipBytes()` Discards a byte-string written by `Encoder.writeBytes(java.nio.ByteBuffer)`.
`protected void`	`skipFixed()`
`void`	`skipFixed(int length)` Discards fixed sized binary object.
`long`	`skipMap()` Support for quickly skipping through a map similar to `Decoder.skipArray()`.
`void`	`skipString()` Discards a char-string written by `Encoder.writeString(org.apache.avro.util.Utf8)`.

Methods inherited from class org.apache.avro.io.ParsingDecoder
skipAction, skipTopSymbol

Methods inherited from class org.apache.avro.io.Decoder
readFixed

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

- Method Detail
  - configure
```
public JsonDecoder configure(InputStream in)
                      throws IOException
```
    Reconfigures this JsonDecoder to use the InputStream provided.
    If the InputStream provided is null, a NullPointerException is thrown.
    Otherwise, this JsonDecoder will reset its state and then reconfigure its input.
    
    Parameters:
    
    in - The InputStream to read from. Cannot be null.
    
    Returns:
    
    this JsonDecoder
    
    Throws:
    
    IOException
  - configure
```
public JsonDecoder configure(String in)
                      throws IOException
```
    Reconfigures this JsonDecoder to use the String provided for input.
    If the String provided is null, a NullPointerException is thrown.
    Otherwise, this JsonDecoder will reset its state and then reconfigure its input.
    
    Parameters:
    
    in - The String to read from. Cannot be null.
    
    Returns:
    
    this JsonDecoder
    
    Throws:
    
    IOException
  - readNull
```
public void readNull()
              throws IOException
```
    Description copied from class: Decoder
    
    "Reads" a null value. (Doesn't actually read anything, but advances the state of the parser if the implementation is stateful.)
    
    Specified by:
    
    readNull in class Decoder
    
    Throws:
    
    IOException
  - readBoolean
```
public boolean readBoolean()
                    throws IOException
```
    Description copied from class: Decoder
    
    Reads a boolean value written by Encoder.writeBoolean(boolean).
    
    Specified by:
    
    readBoolean in class Decoder
    
    Throws:
    
    IOException
  - readInt
```
public int readInt()
            throws IOException
```
    Description copied from class: Decoder
    
    Reads an integer written by Encoder.writeInt(int).
    
    Specified by:
    
    readInt in class Decoder
    
    Throws:
    
    IOException
  - readLong
```
public long readLong()
              throws IOException
```
    Description copied from class: Decoder
    
    Reads a long written by Encoder.writeLong(long).
    
    Specified by:
    
    readLong in class Decoder
    
    Throws:
    
    IOException
  - readFloat
```
public float readFloat()
                throws IOException
```
    Description copied from class: Decoder
    
    Reads a float written by Encoder.writeFloat(float).
    
    Specified by:
    
    readFloat in class Decoder
    
    Throws:
    
    IOException
  - readDouble
```
public double readDouble()
                  throws IOException
```
    Description copied from class: Decoder
    
    Reads a double written by Encoder.writeDouble(double).
    
    Specified by:
    
    readDouble in class Decoder
    
    Throws:
    
    IOException
  - readString
```
public Utf8 readString(Utf8 old)
                throws IOException
```
    Description copied from class: Decoder
    
    Reads a char-string written by Encoder.writeString(org.apache.avro.util.Utf8).
    
    Specified by:
    
    readString in class Decoder
    
    Throws:
    
    IOException
  - readString
```
public String readString()
                  throws IOException
```
    Description copied from class: Decoder
    
    Reads a char-string written by Encoder.writeString(org.apache.avro.util.Utf8).
    
    Specified by:
    
    readString in class Decoder
    
    Throws:
    
    IOException
  - skipString
```
public void skipString()
                throws IOException
```
    Description copied from class: Decoder
    
    Discards a char-string written by Encoder.writeString(org.apache.avro.util.Utf8).
    
    Specified by:
    
    skipString in class Decoder
    
    Throws:
    
    IOException
  - readBytes
```
public ByteBuffer readBytes(ByteBuffer old)
                     throws IOException
```
    Description copied from class: Decoder
    
    Reads a byte-string written by Encoder.writeBytes(java.nio.ByteBuffer). if old is not null and has sufficient capacity to take in the bytes being read, the bytes are returned in old.
    
    Specified by:
    
    readBytes in class Decoder
    
    Throws:
    
    IOException
  - skipBytes
```
public void skipBytes()
               throws IOException
```
    Description copied from class: Decoder
    
    Discards a byte-string written by Encoder.writeBytes(java.nio.ByteBuffer).
    
    Specified by:
    
    skipBytes in class Decoder
    
    Throws:
    
    IOException
  - readFixed
```
public void readFixed(byte[] bytes,
                      int start,
                      int len)
               throws IOException
```
    Description copied from class: Decoder
    
    Reads fixed sized binary object.
    
    Specified by:
    
    readFixed in class Decoder
    
    Parameters:
    
    bytes - The buffer to store the contents being read.
    
    start - The position where the data needs to be written.
    
    len - The size of the binary object.
    
    Throws:
    
    IOException
  - skipFixed
```
public void skipFixed(int length)
               throws IOException
```
    Description copied from class: Decoder
    
    Discards fixed sized binary object.
    
    Specified by:
    
    skipFixed in class Decoder
    
    Parameters:
    
    length - The size of the binary object to be skipped.
    
    Throws:
    
    IOException
  - skipFixed
```
protected void skipFixed()
                  throws IOException
```
    Specified by:
    
    skipFixed in class ParsingDecoder
    
    Throws:
    
    IOException
  - readEnum
```
public int readEnum()
             throws IOException
```
    Description copied from class: Decoder
    
    Reads an enumeration.
    
    Specified by:
    
    readEnum in class Decoder
    
    Returns:
    
    The enumeration's value.
    
    Throws:
    
    IOException
  - readArrayStart
```
public long readArrayStart()
                    throws IOException
```
    Description copied from class: Decoder
    Reads and returns the size of the first block of an array. If this method returns non-zero, then the caller should read the indicated number of items, and then call Decoder.arrayNext() to find out the number of items in the next block. The typical pattern for consuming an array looks like:
```
   for(long i = in.readArrayStart(); i != 0; i = in.arrayNext()) {
     for (long j = 0; j < i; j++) {
       read next element of the array;
     }
   }
 
```
    Specified by:
    
    readArrayStart in class Decoder
    
    Throws:
    
    IOException
  - arrayNext
```
public long arrayNext()
               throws IOException
```
    Description copied from class: Decoder
    
    Processes the next block of an array and returns the number of items in the block and let's the caller read those items.
    
    Specified by:
    
    arrayNext in class Decoder
    
    Throws:
    
    IOException
  - skipArray
```
public long skipArray()
               throws IOException
```
    Description copied from class: Decoder
    Used for quickly skipping through an array. Note you can either skip the entire array, or read the entire array (with Decoder.readArrayStart()), but you can't mix the two on the same array. This method will skip through as many items as it can, all of them if possible. It will return zero if there are no more items to skip through, or an item count if it needs the client's help in skipping. The typical usage pattern is:
```
   for(long i = in.skipArray(); i != 0; i = i.skipArray()) {
     for (long j = 0; j < i; j++) {
       read and discard the next element of the array;
     }
   }
 
```
    Note that this method can automatically skip through items if a byte-count is found in the underlying data, or if a schema has been provided to the implementation, but otherwise the client will have to skip through items itself.
    Specified by:
    
    skipArray in class Decoder
    
    Throws:
    
    IOException
  - readMapStart
```
public long readMapStart()
                  throws IOException
```
    Description copied from class: Decoder
    Reads and returns the size of the next block of map-entries. Similar to Decoder.readArrayStart(). As an example, let's say you want to read a map of records, the record consisting of an Long field and a Boolean field. Your code would look something like this:
```
 Map m = new HashMap();
 Record reuse = new Record();
 for (long i = in.readMapStart(); i != 0; i = in.readMapNext()) {
   for (long j = 0; j < i; j++) {
     String key = in.readString();
     reuse.intField = in.readInt();
     reuse.boolField = in.readBoolean();
     m.put(key, reuse);
   }
 }
 
```
    Specified by:
    
    readMapStart in class Decoder
    
    Throws:
    
    IOException
  - mapNext
```
public long mapNext()
             throws IOException
```
    Description copied from class: Decoder
    
    Processes the next block of map entries and returns the count of them. Similar to Decoder.arrayNext(). See Decoder.readMapStart() for details.
    
    Specified by:
    
    mapNext in class Decoder
    
    Throws:
    
    IOException
  - skipMap
```
public long skipMap()
             throws IOException
```
    Description copied from class: Decoder
    Support for quickly skipping through a map similar to Decoder.skipArray(). As an example, let's say you want to skip a map of records, the record consisting of an Long field and a Boolean field. Your code would look something like this:
```
 for (long i = in.skipMap(); i != 0; i = in.skipMap()) {
   for (long j = 0; j < i; j++) {
     in.skipString(); // Discard key
     in.readInt(); // Discard int-field of value
     in.readBoolean(); // Discard boolean-field of value
   }
 }
 
```
    Specified by:
    
    skipMap in class Decoder
    
    Throws:
    
    IOException
  - readIndex
```
public int readIndex()
              throws IOException
```
    Description copied from class: Decoder
    
    Reads the tag of a union written by Encoder.writeIndex(int).
    
    Specified by:
    
    readIndex in class Decoder
    
    Throws:
    
    IOException
  - doAction
```
public Symbol doAction(Symbol input,
                       Symbol top)
                throws IOException
```
    Description copied from interface: Parser.ActionHandler
    
    Handle the action symbol top when the input is sought to be taken off the stack.
    
    Specified by:
    
    doAction in interface Parser.ActionHandler
    
    Parameters:
    
    input - The input symbol from the caller of advance
    
    top - The symbol at the top the stack.
    
    Returns:
    
    null if advance() is to continue processing the stack. If not null the return value will be returned by advance().
    
    Throws:
    
    IOException

Class JsonDecoder

Field Summary

Fields inherited from class org.apache.avro.io.ParsingDecoder

Method Summary

Methods inherited from class org.apache.avro.io.ParsingDecoder

Methods inherited from class org.apache.avro.io.Decoder

Methods inherited from class java.lang.Object

Method Detail

configure

configure

readNull

readBoolean

readInt

readLong

readFloat

readDouble

readString

readString

skipString

readBytes

skipBytes

readFixed

skipFixed

skipFixed

readEnum

readArrayStart

arrayNext

skipArray

readMapStart

mapNext

skipMap

readIndex

doAction