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/filter/TokenFilter.java

package com.fasterxml.jackson.core.filter;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;

/**
 * Strategy class that can be implemented to specify actual inclusion/exclusion
 * criteria for filtering, used by {@link FilteringGeneratorDelegate}.
 *
 * @since 2.6
 */
public class TokenFilter
{
    /**
     * Enumeration that controls how TokenFilter return values are interpreted.
     *
     * @since 2.12
     */
    public enum Inclusion {
        /**
         * Tokens will only be included if the filter returns TokenFilter.INCLUDE_ALL
         */
        ONLY_INCLUDE_ALL,
        /**
         * When TokenFilter.INCLUDE_ALL is returned, the corresponding token will
         * be included as well as enclosing tokens up to the root
         */
        INCLUDE_ALL_AND_PATH,
        /**
         * Tokens will be included if any non-null filter is returned.
         * The exception is if a field name returns a non-null filter,
         * but the field value returns a null filter. In this case the
         * field name and value will both be omitted.
         */
        INCLUDE_NON_NULL
    }

    // // Marker values

    /**
     * Marker value that should be used to indicate inclusion of a structured
     * value (sub-tree representing Object or Array), or value of a named
     * property (regardless of type).
     * Note that if this instance is returned, it will used as a marker, and 
     * no actual callbacks need to be made. For this reason, it is more efficient
     * to return this instance if the whole sub-tree is to be included, instead
     * of implementing similar filter functionality explicitly.
     */
    public final static TokenFilter INCLUDE_ALL = new TokenFilter();

    // Life-cycle

    protected TokenFilter() { }

    /*
    /**********************************************************************
    /* API, structured values
    /**********************************************************************
     */

    /**
     * Method called to check whether Object value at current output
     * location should be included in output.
     * Three kinds of return values may be used as follows:
     *<ul>
     * <li><code>null</code> to indicate that the Object should be skipped
     *   </li>
     * <li>{@link #INCLUDE_ALL} to indicate that the Object should be included
     * completely in output
     *   </li>
     * <li>Any other {@link TokenFilter} implementation (possibly this one) to mean
     *  that further inclusion calls on return filter object need to be made
     *  on contained properties, as necessary. {@link #filterFinishObject()} will
     *  also be called on returned filter object
     *   </li>
     * </ul>
     *<p>
     * Default implementation returns <code>this</code>, which means that checks
     * are made recursively for properties of the Object to determine possible inclusion.
     * 
     * @return TokenFilter to use for further calls within Array, unless return value
     *   is <code>null</code> or {@link #INCLUDE_ALL} (which have simpler semantics)
     */
    public TokenFilter filterStartObject() {
        return this;
    }

    /**
     * Method called to check whether Array value at current output
     * location should be included in output.
     * Three kinds of return values may be used as follows:
     *<ul>
     * <li><code>null</code> to indicate that the Array should be skipped
     *   </li>
     * <li>{@link #INCLUDE_ALL} to indicate that the Array should be included
     * completely in output
     *   </li>
     * <li>Any other {@link TokenFilter} implementation (possibly this one) to mean
     *  that further inclusion calls on return filter object need to be made
     *  on contained element values, as necessary. {@link #filterFinishArray()} will
     *  also be called on returned filter object
     *   </li>
     * </ul>
     *<p>
     * Default implementation returns <code>this</code>, which means that checks
     * are made recursively for elements of the array to determine possible inclusion.
     * 
     * @return TokenFilter to use for further calls within Array, unless return value
     *   is <code>null</code> or {@link #INCLUDE_ALL} (which have simpler semantics)
     */
    public TokenFilter filterStartArray() {
        return this;
    }

    /**
     * Method called to indicate that output of non-filtered Object (one that may
     * have been included either completely, or in part) is completed,
     * in cases where filter other that {@link #INCLUDE_ALL} was returned.
     * This occurs when {@link JsonGenerator#writeEndObject()} is called.
     */
    public void filterFinishObject() { }

    /**
     * Method called to indicate that output of non-filtered Array (one that may
     * have been included either completely, or in part) is completed,
     * in cases where filter other that {@link #INCLUDE_ALL} was returned.
     * This occurs when {@link JsonGenerator#writeEndArray()} is called.
     */
    public void filterFinishArray() { }

    /*
    /**********************************************************************
    /* API, properties/elements
    /**********************************************************************
     */

    /**
     * Method called to check whether property value with specified name,
     * at current output location, should be included in output.
     * Three kinds of return values may be used as follows:
     *<ul>
     * <li><code>null</code> to indicate that the property and its value should be skipped
     *   </li>
     * <li>{@link #INCLUDE_ALL} to indicate that the property and its value should be included
     * completely in output
     *   </li>
     * <li>Any other {@link TokenFilter} implementation (possibly this one) to mean
     *  that further inclusion calls on returned filter object need to be made
     *  as necessary, to determine inclusion.
     *   </li>
     * </ul>
     *<p>
     * The default implementation simply returns <code>this</code> to continue calling
     * methods on this filter object, without full inclusion or exclusion.
     * 
     * @param name Name of Object property to check
     *
     * @return TokenFilter to use for further calls within property value, unless return value
     *   is <code>null</code> or {@link #INCLUDE_ALL} (which have simpler semantics)
     */
    public TokenFilter includeProperty(String name) {
        return this;
    }

    /**
     * Method called to check whether array element with specified index (zero-based),
     * at current output location, should be included in output.
     * Three kinds of return values may be used as follows:
     *<ul>
     * <li><code>null</code> to indicate that the Array element should be skipped
     *   </li>
     * <li>{@link #INCLUDE_ALL} to indicate that the Array element should be included
     * completely in output
     *   </li>
     * <li>Any other {@link TokenFilter} implementation (possibly this one) to mean
     *  that further inclusion calls on returned filter object need to be made
     *  as necessary, to determine inclusion.
     *   </li>
     * </ul>
     *<p>
     * The default implementation simply returns <code>this</code> to continue calling
     * methods on this filter object, without full inclusion or exclusion.
     *
     * @param index Array element index (0-based) to check
     *
     * @return TokenFilter to use for further calls within element value, unless return value
     *   is <code>null</code> or {@link #INCLUDE_ALL} (which have simpler semantics)
     */
    public TokenFilter includeElement(int index) {
        return this;
    }

    /**
     * Method called to check whether root-level value,
     * at current output location, should be included in output.
     * Three kinds of return values may be used as follows:
     *<ul>
     * <li><code>null</code> to indicate that the root value should be skipped
     *   </li>
     * <li>{@link #INCLUDE_ALL} to indicate that the root value should be included
     * completely in output
     *   </li>
     * <li>Any other {@link TokenFilter} implementation (possibly this one) to mean
     *  that further inclusion calls on returned filter object need to be made
     *  as necessary, to determine inclusion.
     *   </li>
     * </ul>
     *<p>
     * The default implementation simply returns <code>this</code> to continue calling
     * methods on this filter object, without full inclusion or exclusion.
     *
     * @param index Index (0-based) of the root value to check
     *
     * @return TokenFilter to use for further calls within root value, unless return value
     *   is <code>null</code> or {@link #INCLUDE_ALL} (which have simpler semantics)
     */
    public TokenFilter includeRootValue(int index) {
        return this;
    }

    /*
    /**********************************************************************
    /* API, scalar values (being read)
    /**********************************************************************
     */

    /**
     * Call made when verifying whether a scalar value is being
     * read from a parser.
     *<p>
     * Default action is to call <code>_includeScalar()</code> and return
     * whatever it indicates.
     *
     * @param p Parser that points to the value (typically {@code delegate}
     *    parser, not filtering parser that wraps it)
     *
     * @return True if scalar value is to be included; false if not
     *
     * @throws IOException if there are any problems reading content (typically
     *   via calling passed-in {@code JsonParser})
     */
    public boolean includeValue(JsonParser p) throws IOException {
        return _includeScalar();
    }

    /*
    /**********************************************************************
    /* API, scalar values (being written)
    /**********************************************************************
     */

    /**
     * Call made to verify whether leaf-level
     * boolean value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeBoolean(boolean value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * null value
     * should be included in output or not.
     *
     * @return True if ({@code null}) value is to be included; false if not
     */
    public boolean includeNull() {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * String value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeString(String value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * "streaming" String value
     * should be included in output or not.
     *<p>
     * NOTE: note that any reads from passed in {@code Reader} may lead
     * to actual loss of content to write; typically method should NOT
     * access content passed via this method.
     *
     * @param r Reader used to pass String value to parser
     * @param maxLen indicated maximum length of String value
     *
     * @return True if value is to be included; false if not
     *
     * @since 2.11
     */
    public boolean includeString(java.io.Reader r, int maxLen) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * <code>int</code> value
     * should be included in output or not.
     * 
     * NOTE: also called for `short`, `byte`
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(int value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * <code>long</code> value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(long value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * <code>float</code> value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(float value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * <code>double</code> value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(double value) {
        return _includeScalar();
    }
    
    /**
     * Call made to verify whether leaf-level
     * {@link BigDecimal} value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(BigDecimal value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * {@link BigInteger} value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeNumber(BigInteger value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * Binary value
     * should be included in output or not.
     *<p>
     * NOTE: no binary payload passed; assumption is this won't be of much use.
     *
     * @return True if the binary value is to be included; false if not
     */
    public boolean includeBinary() {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level
     * raw (pre-encoded, not quoted by generator) value
     * should be included in output or not.
     *<p>
     * NOTE: value itself not passed since it may come on multiple forms
     * and is unlikely to be of much use in determining inclusion
     * criteria.
     *
     * @return True if the raw value is to be included; false if not
     */
    public boolean includeRawValue() {
        return _includeScalar();
    }
    
    /**
     * Call made to verify whether leaf-level
     * embedded (Opaque) value
     * should be included in output or not.
     *
     * @param value Value to check
     *
     * @return True if value is to be included; false if not
     */
    public boolean includeEmbeddedValue(Object value) {
        return _includeScalar();
    }

    /**
     * Call made to verify whether leaf-level empty Array value
     * should be included in output or not.
     *
     * @param contentsFiltered True if Array had contents but they were
     *   filtered out (NOT included); false if we had actual empty Array.
     *
     * @return True if value is to be included; false if not
     *
     * @since 2.14
     */
    public boolean includeEmptyArray(boolean contentsFiltered) {
        return false;
    }

    /**
     * Call made to verify whether leaf-level empty Object value
     * should be included in output or not.
     *
     * @param contentsFiltered True if Object had contents but they were
     *   filtered out (NOT included); false if we had actual empty Object.
     *
     * @return True if value is to be included; false if not
     *
     * @since 2.14
     */
    public boolean includeEmptyObject(boolean contentsFiltered) {
        return false;
    }

    /*
    /**********************************************************************
    /* Overrides
    /**********************************************************************
     */

    @Override
    public String toString() {
        if (this == INCLUDE_ALL) {
            return "TokenFilter.INCLUDE_ALL";
        }
        return super.toString();
    }

    /*
    /**********************************************************************
    /* Other methods
    /**********************************************************************
     */
    
    /**
     * Overridable default implementation delegated to all scalar value
     * inclusion check methods.
     * The default implementation simply includes all leaf values.
     *
     * @return Whether all leaf scalar values should be included ({@code true})
     *    or not ({@code false})
     */
    protected boolean _includeScalar() {
        return true;
    }
}

⏎ com/fasterxml/jackson/core/filter/TokenFilter.java

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