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-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Core Source Code below:

⏎ com/fasterxml/jackson/core/PrettyPrinter.java

/* Jackson JSON-processor.
 *
 * Copyright (c) 2007- Tatu Saloranta, tatu.saloranta@iki.fi
 */

package com.fasterxml.jackson.core;

import java.io.IOException;

import com.fasterxml.jackson.core.io.SerializedString;
import com.fasterxml.jackson.core.util.Separators;

/**
 * Interface for objects that implement pretty printer functionality, such
 * as indentation.
 * Pretty printers are used to add white space in output JSON content,
 * to make results more human readable. Usually this means things like adding
 * linefeeds and indentation.
 *<p>
 * Note: since Jackson 2.1, stateful implementations MUST implement
 * {@link com.fasterxml.jackson.core.util.Instantiatable} interface,
 * to allow for constructing  per-generation instances and avoid
 * state corruption.
 * Stateless implementations need not do this; but those are less common.
 */
public interface PrettyPrinter
{
    /**
     * @since 2.9
     */
    public final static Separators DEFAULT_SEPARATORS = Separators.createDefaultInstance();

    /**
     * Default String used for separating root values is single space.
     * 
     * @since 2.9
     */
    public final static SerializedString DEFAULT_ROOT_VALUE_SEPARATOR = new SerializedString(" ");

    /*
    /**********************************************************
    /* First methods that act both as events, and expect
    /* output for correct functioning (i.e something gets
    /* output even when not pretty-printing)
    /**********************************************************
     */

    // // // Root-level handling:

    /**
     * Method called after a root-level value has been completely
     * output, and before another value is to be output.
     *<p>
     * Default handling (without pretty-printing) will output a space, to
     * allow values to be parsed correctly. Pretty-printer is
     * to output some other suitable and nice-looking separator
     * (tab(s), space(s), linefeed(s) or any combination thereof).
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeRootValueSeparator(JsonGenerator gen) throws IOException;

    // // Object handling

    /**
     * Method called when an Object value is to be output, before
     * any fields are output.
     *<p>
     * Default handling (without pretty-printing) will output
     * the opening curly bracket.
     * Pretty-printer is
     * to output a curly bracket as well, but can surround that
     * with other (white-space) decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeStartObject(JsonGenerator gen) throws IOException;

    /**
     * Method called after an Object value has been completely output
     * (minus closing curly bracket).
     *<p>
     * Default handling (without pretty-printing) will output
     * the closing curly bracket.
     * Pretty-printer is
     * to output a curly bracket as well, but can surround that
     * with other (white-space) decoration.
     *
     * @param gen Generator used for output
     * @param nrOfEntries Number of direct members of the Object that
     *   have been output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeEndObject(JsonGenerator gen, int nrOfEntries) throws IOException;

    /**
     * Method called after an Object entry (field:value) has been completely
     * output, and before another value is to be output.
     *<p>
     * Default handling (without pretty-printing) will output a single
     * comma to separate the two. Pretty-printer is
     * to output a comma as well, but can surround that with other
     * (white-space) decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeObjectEntrySeparator(JsonGenerator gen) throws IOException;

    /**
     * Method called after an object field has been output, but
     * before the value is output.
     *<p>
     * Default handling (without pretty-printing) will output a single
     * colon to separate the two. Pretty-printer is
     * to output a colon as well, but can surround that with other
     * (white-space) decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeObjectFieldValueSeparator(JsonGenerator gen) throws IOException;

    // // // Array handling

    /**
     * Method called when an Array value is to be output, before
     * any member/child values are output.
     *<p>
     * Default handling (without pretty-printing) will output
     * the opening bracket.
     * Pretty-printer is
     * to output a bracket as well, but can surround that
     * with other (white-space) decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeStartArray(JsonGenerator gen) throws IOException;

    /**
     * Method called after an Array value has been completely output
     * (minus closing bracket).
     *<p>
     * Default handling (without pretty-printing) will output
     * the closing bracket.
     * Pretty-printer is
     * to output a bracket as well, but can surround that
     * with other (white-space) decoration.
     *
     * @param gen Generator used for output
     * @param nrOfValues Number of direct members of the array that
     *   have been output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeEndArray(JsonGenerator gen, int nrOfValues) throws IOException;

    /**
     * Method called after an array value has been completely
     * output, and before another value is to be output.
     *<p>
     * Default handling (without pretty-printing) will output a single
     * comma to separate the two. Pretty-printer is
     * to output a comma as well, but can surround that with other
     * (white-space) decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void writeArrayValueSeparator(JsonGenerator gen) throws IOException;

    /*
    /**********************************************************
    /* Then events that by default do not produce any output but that are
    /* often overridden to add white space in pretty-printing mode
    /**********************************************************
     */

    /**
     * Method called after array start marker has been output,
     * and right before the first value is to be output.
     * It is <b>not</b> called for arrays with no values.
     *<p>
     * Default handling does not output anything, but pretty-printer
     * is free to add any white space decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void beforeArrayValues(JsonGenerator gen) throws IOException;

    /**
     * Method called after object start marker has been output,
     * and right before the field name of the first entry is
     * to be output.
     * It is <b>not</b> called for objects without entries.
     *<p>
     * Default handling does not output anything, but pretty-printer
     * is free to add any white space decoration.
     *
     * @param gen Generator used for output
     *
     * @throws IOException if there is either an underlying I/O problem or encoding
     *    issue at format layer
     */
    void beforeObjectEntries(JsonGenerator gen) throws IOException;
}

⏎ com/fasterxml/jackson/core/PrettyPrinter.java

Or download all of them as a single archive file:

File name: jackson-core-2.14.0-sources.jar
File size: 497693 bytes
Release date: 2022-11-05
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