Jackson Core Source Code

Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Core Source Code files are provided in the source packge (jackson-core-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Core Source Code below:

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com/fasterxml/jackson/core/io/IOContext.java

package com.fasterxml.jackson.core.io;

import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.util.BufferRecycler;
import com.fasterxml.jackson.core.util.TextBuffer;

/**
 * To limit number of configuration and state objects to pass, all
 * contextual objects that need to be passed by the factory to
 * readers and writers are combined under this object. One instance
 * is created for each reader and writer.
 *<p>
 * NOTE: non-final since 2.4, to allow sub-classing.
 */
public class IOContext
{
    /*
    /**********************************************************
    /* Configuration
    /**********************************************************
     */

    /**
     * Reference to the source object, which can be used for displaying
     * location information
     */
    protected final Object _sourceRef;

    /**
     * Encoding used by the underlying stream, if known.
     */
    protected JsonEncoding _encoding;

    /**
     * Flag that indicates whether underlying input/output source/target
     * object is fully managed by the owner of this context (parser or
     * generator). If true, it is, and is to be closed by parser/generator;
     * if false, calling application has to do closing (unless auto-closing
     * feature is enabled for the parser/generator in question; in which
     * case it acts like the owner).
     */
    protected final boolean _managedResource;

    /*
    /**********************************************************
    /* Buffer handling, recycling
    /**********************************************************
     */

    /**
     * Recycler used for actual allocation/deallocation/reuse
     */
    protected final BufferRecycler _bufferRecycler;

    /**
     * Reference to the allocated I/O buffer for low-level input reading,
     * if any allocated.
     */
    protected byte[] _readIOBuffer;

    /**
     * Reference to the allocated I/O buffer used for low-level
     * encoding-related buffering.
     */
    protected byte[] _writeEncodingBuffer;
    
    /**
     * Reference to the buffer allocated for temporary use with
     * base64 encoding or decoding.
     */
    protected byte[] _base64Buffer;

    /**
     * Reference to the buffer allocated for tokenization purposes,
     * in which character input is read, and from which it can be
     * further returned.
     */
    protected char[] _tokenCBuffer;

    /**
     * Reference to the buffer allocated for buffering it for
     * output, before being encoded: generally this means concatenating
     * output, then encoding when buffer fills up.
     */
    protected char[] _concatCBuffer;

    /**
     * Reference temporary buffer Parser instances need if calling
     * app decides it wants to access name via 'getTextCharacters' method.
     * Regular text buffer can not be used as it may contain textual
     * representation of the value token.
     */
    protected char[] _nameCopyBuffer;

    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    public IOContext(BufferRecycler br, Object sourceRef, boolean managedResource)
    {
        _bufferRecycler = br;
        _sourceRef = sourceRef;
        _managedResource = managedResource;
    }

    public void setEncoding(JsonEncoding enc) {
        _encoding = enc;
    }

    public IOContext withEncoding(JsonEncoding enc) {
        _encoding = enc;
        return this;
    }
    
    /*
    /**********************************************************
    /* Public API, accessors
    /**********************************************************
     */

    public Object getSourceReference() { return _sourceRef; }
    public JsonEncoding getEncoding() { return _encoding; }
    public boolean isResourceManaged() { return _managedResource; }

    /*
    /**********************************************************
    /* Public API, buffer management
    /**********************************************************
     */

    public TextBuffer constructTextBuffer() {
        return new TextBuffer(_bufferRecycler);
    }

    /**
     * Method for recycling or allocation byte buffer of "read I/O" type.
     *<p>
     * Note: the method can only be called once during its life cycle.
     * This is to protect against accidental sharing.
     *
     * @return Allocated or recycled byte buffer
     */
    public byte[] allocReadIOBuffer() {
        _verifyAlloc(_readIOBuffer);
        return (_readIOBuffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_READ_IO_BUFFER));
    }

    /**
     * Variant of {@link #allocReadIOBuffer()} that specifies smallest acceptable
     * buffer size.
     *
     * @param minSize Minimum size of the buffer to recycle or allocate
     *
     * @return Allocated or recycled byte buffer
     *
     * @since 2.4
     */
    public byte[] allocReadIOBuffer(int minSize) {
        _verifyAlloc(_readIOBuffer);
        return (_readIOBuffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_READ_IO_BUFFER, minSize));
    }

    /**
     * Method for recycling or allocation byte buffer of "write encoding" type.
     *<p>
     * Note: the method can only be called once during its life cycle.
     * This is to protect against accidental sharing.
     *
     * @return Allocated or recycled byte buffer
     */
    public byte[] allocWriteEncodingBuffer() {
        _verifyAlloc(_writeEncodingBuffer);
        return (_writeEncodingBuffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_WRITE_ENCODING_BUFFER));
    }

    /**
     * Variant of {@link #allocWriteEncodingBuffer()} that specifies smallest acceptable
     * buffer size.
     *
     * @param minSize Minimum size of the buffer to recycle or allocate
     *
     * @return Allocated or recycled byte buffer
     *
     * @since 2.4
     */
    public byte[] allocWriteEncodingBuffer(int minSize) {
        _verifyAlloc(_writeEncodingBuffer);
        return (_writeEncodingBuffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_WRITE_ENCODING_BUFFER, minSize));
    }

    /**
     * Method for recycling or allocation byte buffer of "base 64 encode/decode" type.
     *<p>
     * Note: the method can only be called once during its life cycle.
     * This is to protect against accidental sharing.
     *
     * @return Allocated or recycled byte buffer
     */
    public byte[] allocBase64Buffer() {
        _verifyAlloc(_base64Buffer);
        return (_base64Buffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_BASE64_CODEC_BUFFER));
    }

    /**
     * Variant of {@link #allocBase64Buffer()} that specifies smallest acceptable
     * buffer size.
     *
     * @param minSize Minimum size of the buffer to recycle or allocate
     *
     * @return Allocated or recycled byte buffer
     *
     * @since 2.9
     */
    public byte[] allocBase64Buffer(int minSize) {
        _verifyAlloc(_base64Buffer);
        return (_base64Buffer = _bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_BASE64_CODEC_BUFFER, minSize));
    }
    
    public char[] allocTokenBuffer() {
        _verifyAlloc(_tokenCBuffer);
        return (_tokenCBuffer = _bufferRecycler.allocCharBuffer(BufferRecycler.CHAR_TOKEN_BUFFER));
    }

    // @since 2.4
    public char[] allocTokenBuffer(int minSize) {
        _verifyAlloc(_tokenCBuffer);
        return (_tokenCBuffer = _bufferRecycler.allocCharBuffer(BufferRecycler.CHAR_TOKEN_BUFFER, minSize));
    }
    
    public char[] allocConcatBuffer() {
        _verifyAlloc(_concatCBuffer);
        return (_concatCBuffer = _bufferRecycler.allocCharBuffer(BufferRecycler.CHAR_CONCAT_BUFFER));
    }

    public char[] allocNameCopyBuffer(int minSize) {
        _verifyAlloc(_nameCopyBuffer);
        return (_nameCopyBuffer = _bufferRecycler.allocCharBuffer(BufferRecycler.CHAR_NAME_COPY_BUFFER, minSize));
    }

    /**
     * Method to call when all the processing buffers can be safely
     * recycled.
     *
     * @param buf Buffer instance to release (return for recycling)
     */
    public void releaseReadIOBuffer(byte[] buf) {
        if (buf != null) {
            // Let's do sanity checks to ensure once-and-only-once release,
            // as well as avoiding trying to release buffers not owned
            _verifyRelease(buf, _readIOBuffer);
            _readIOBuffer = null;
            _bufferRecycler.releaseByteBuffer(BufferRecycler.BYTE_READ_IO_BUFFER, buf);
        }
    }

    public void releaseWriteEncodingBuffer(byte[] buf) {
        if (buf != null) {
            // Let's do sanity checks to ensure once-and-only-once release,
            // as well as avoiding trying to release buffers not owned
            _verifyRelease(buf, _writeEncodingBuffer);
            _writeEncodingBuffer = null;
            _bufferRecycler.releaseByteBuffer(BufferRecycler.BYTE_WRITE_ENCODING_BUFFER, buf);
        }
    }

    public void releaseBase64Buffer(byte[] buf) {
        if (buf != null) { // sanity checks, release once-and-only-once, must be one owned
            _verifyRelease(buf, _base64Buffer);
            _base64Buffer = null;
            _bufferRecycler.releaseByteBuffer(BufferRecycler.BYTE_BASE64_CODEC_BUFFER, buf);
        }
    }
    
    public void releaseTokenBuffer(char[] buf) {
        if (buf != null) {
            _verifyRelease(buf, _tokenCBuffer);
            _tokenCBuffer = null;
            _bufferRecycler.releaseCharBuffer(BufferRecycler.CHAR_TOKEN_BUFFER, buf);
        }
    }

    public void releaseConcatBuffer(char[] buf) {
        if (buf != null) {
            // 14-Jan-2014, tatu: Let's actually allow upgrade of the original buffer.
            _verifyRelease(buf, _concatCBuffer);
            _concatCBuffer = null;
            _bufferRecycler.releaseCharBuffer(BufferRecycler.CHAR_CONCAT_BUFFER, buf);
        }
    }

    public void releaseNameCopyBuffer(char[] buf) {
        if (buf != null) {
            // 14-Jan-2014, tatu: Let's actually allow upgrade of the original buffer.
            _verifyRelease(buf, _nameCopyBuffer);
            _nameCopyBuffer = null;
            _bufferRecycler.releaseCharBuffer(BufferRecycler.CHAR_NAME_COPY_BUFFER, buf);
        }
    }

    /*
    /**********************************************************************
    /* Internal helpers
    /**********************************************************************
     */

    protected final void _verifyAlloc(Object buffer) {
        if (buffer != null) { throw new IllegalStateException("Trying to call same allocXxx() method second time"); }
    }

    protected final void _verifyRelease(byte[] toRelease, byte[] src) {
        // 07-Mar-2016, tatu: As per [core#255], only prevent shrinking of buffer
        if ((toRelease != src) && (toRelease.length < src.length)) { throw wrongBuf(); }
    }

    protected final void _verifyRelease(char[] toRelease, char[] src) {
        // 07-Mar-2016, tatu: As per [core#255], only prevent shrinking of buffer
        if ((toRelease != src) && (toRelease.length < src.length)) { throw wrongBuf(); }
    }

    private IllegalArgumentException wrongBuf() {
        // sanity check failed; trying to return different, smaller buffer.
        return new IllegalArgumentException("Trying to release buffer smaller than original");
    }
}

com/fasterxml/jackson/core/io/IOContext.java

 

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