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## org.apache.lucene.util.encoding
Class IntEncoder

    java.lang.Object
      org.apache.lucene.util.encoding.IntEncoder

Direct Known Subclasses:
  ChunksIntEncoder, IntEncoderFilter, SimpleIntEncoder, VInt8IntEncoder

    public abstract class IntEncoder

extends Object

Encodes integers to a set `OutputStream`. Extending classes need to override `encode(int)` to encode the value using their encoding algorithm. The default implementation of `close()` closes the set `OutputStream`.

The default `constructor` is provided for convenience only. One must call `reInit(OutputStream)` before calling `encode(int)` or `close()`.

For convenience, each encoder implements `createMatchingDecoder()` for easy access to the matching decoder.

NOTE: some implementations may buffer the encoded values in memory (such as `IntEncoderFilter` implementations) and encoding will happen only upon calling `close()`. Therefore it is important to always call `close()` on the encoder at hand.

NOTE: encoders are usually not thread safe, unless specifically documented otherwise by an implementation.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary
`protected OutputStream` | `out`

Constructor Summary
`IntEncoder()` Default constructor, provided here for robustness: if in the future a constructor with parameters will be added, this might break custom implementations of this class which call this implicit constructor.

Method Summary
`void` | `close()` Instructs the encoder to finish the encoding process.
`abstract IntDecoder` | `createMatchingDecoder()` Returns an `IntDecoder` which matches this encoder.
`abstract void` | `encode(int value)` Encodes an integer to the output stream given in `reInit`
`void` | `reInit(OutputStream out)` Reinitializes the encoder with the give `OutputStream`.

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

Field Detail

### out

    protected OutputStream out

Constructor Detail

### IntEncoder

    public IntEncoder()

  Default constructor, provided here for robustness: if in the future a constructor with parameters will be added, this might break custom implementations of this class which call this implicit constructor. So we make it explicit to avoid any such issue in the future.

Method Detail

### close

    public void close()
               throws IOException

  Instructs the encoder to finish the encoding process. This method closes the output stream which was specified by `reInit`. An implementation may do here additional cleanup required to complete the encoding, such as flushing internal buffers, etc.
  Once this method was called, no further calls to `encode` should be made before first calling `reInit`.

  NOTE: overriding classes should make sure they either call `super.close()` or close the output stream themselves.

  Throws:
    `IOException`

### encode

    public abstract void encode(int value)
                         throws IOException

  Encodes an integer to the output stream given in `reInit`

  Throws:
    `IOException`

### createMatchingDecoder

    public abstract IntDecoder createMatchingDecoder()

  Returns an `IntDecoder` which matches this encoder. Every encoder must return an `IntDecoder` and `null` is not a valid value. If an encoder is just a filter, it should at least return its wrapped encoder's matching decoder.

  NOTE: this method should create a new instance of the matching decoder and leave the instance sharing to the caller. Returning the same instance over and over is risky because encoders and decoders are not thread safe.

### reInit

    public void reInit(OutputStream out)

  Reinitializes the encoder with the give `OutputStream`. For re-usability it can be changed without the need to reconstruct a new object.

  NOTE: after calling `close()`, one must call this method even if the output stream itself hasn't changed. An example case is that the output stream wraps a byte[], and the output stream itself is reset, but its instance hasn't changed. Some implementations of `IntEncoder` may write some metadata about themselves to the output stream, and therefore it is imperative that one calls this method before encoding any data.

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