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/JsonPointerBasedFilter.java

package com.fasterxml.jackson.core.filter;

import com.fasterxml.jackson.core.JsonPointer;

/**
 * Simple {@link TokenFilter} implementation that takes a single
 * {@link JsonPointer} and matches a single value accordingly.
 * Instances are immutable and fully thread-safe, shareable,
 * and efficient to use.
 * 
 * @since 2.6
 */
public class JsonPointerBasedFilter extends TokenFilter
{
    protected final JsonPointer _pathToMatch;

    public JsonPointerBasedFilter(String ptrExpr) {
        this(JsonPointer.compile(ptrExpr));
    }

    public JsonPointerBasedFilter(JsonPointer match) {
        _pathToMatch = match;
    }

    @Override
    public TokenFilter includeElement(int index) {
        JsonPointer next = _pathToMatch.matchElement(index);
        if (next == null) {
            return null;
        }
        if (next.matches()) {
            return TokenFilter.INCLUDE_ALL;
        }
        return new JsonPointerBasedFilter(next);
    }

    @Override
    public TokenFilter includeProperty(String name) {
        JsonPointer next = _pathToMatch.matchProperty(name);
        if (next == null) {
            return null;
        }
        if (next.matches()) {
            return TokenFilter.INCLUDE_ALL;
        }
        return new JsonPointerBasedFilter(next);
    }

    @Override
    public TokenFilter filterStartArray() {
        return this;
    }
    
    @Override
    public TokenFilter filterStartObject() {
        return this;
    }
    
    @Override
    protected boolean _includeScalar() {
        // should only occur for root-level scalars, path "/"
        return _pathToMatch.matches();
    }

    @Override
    public String toString() {
        return "[JsonPointerFilter at: "+_pathToMatch+"]";
    }
}

⏎ com/fasterxml/jackson/core/filter/JsonPointerBasedFilter.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
Download 

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⇑⇑ Jackson - Java JSON library