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:

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

package com.fasterxml.jackson.core.filter;

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

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.filter.TokenFilter.Inclusion;
import com.fasterxml.jackson.core.util.JsonGeneratorDelegate;

/**
 * Specialized {@link JsonGeneratorDelegate} that allows use of
 * {@link TokenFilter} for outputting a subset of content that
 * caller tries to generate.
 * 
 * @since 2.6
 */
public class FilteringGeneratorDelegate extends JsonGeneratorDelegate
{

    /*
    /**********************************************************
    /* Configuration
    /**********************************************************
     */
    
    /**
     * Object consulted to determine whether to write parts of content generator
     * is asked to write or not.
     */
    protected TokenFilter rootFilter;

    /**
     * Flag that determines whether filtering will continue after the first
     * match is indicated or not: if `false`, output is based on just the first
     * full match (returning {@link TokenFilter#INCLUDE_ALL}) and no more
     * checks are made; if `true` then filtering will be applied as necessary
     * until end of content.
     */
    protected boolean _allowMultipleMatches;

    /**
     * Flag that determines whether path leading up to included content should
     * also be automatically included or not. If `false`, no path inclusion is
     * done and only explicitly included entries are output; if `true` then
     * path from main level down to match is also included as necessary.
     */
    protected TokenFilter.Inclusion _inclusion;

    /*
    /**********************************************************
    /* Additional state
    /**********************************************************
     */

    /**
     * Although delegate has its own output context it is not sufficient since we actually
     * have to keep track of excluded (filtered out) structures as well as ones delegate
     * actually outputs.
     */
    protected TokenFilterContext _filterContext;

    /**
     * State that applies to the item within container, used where applicable.
     * Specifically used to pass inclusion state between property name and
     * property, and also used for array elements.
     */
    protected TokenFilter _itemFilter;
    
    /**
     * Number of tokens for which {@link TokenFilter#INCLUDE_ALL}
     * has been returned
     */
    protected int _matchCount;

    /*
    /**********************************************************
    /* Construction, initialization
    /**********************************************************
     */

    /**
     * @deprecated since 2.12 Use the constructor that takes {@link TokenFilter.Inclusion}
     *    argument instead.
     */
    @Deprecated
    public FilteringGeneratorDelegate(JsonGenerator d, TokenFilter f,
            boolean includePath, boolean allowMultipleMatches)
    {
        this(d, f, includePath ? Inclusion.INCLUDE_ALL_AND_PATH : Inclusion.ONLY_INCLUDE_ALL, allowMultipleMatches);
    }

    /**
     * @since 2.12
     */
    public FilteringGeneratorDelegate(JsonGenerator d, TokenFilter f,
            TokenFilter.Inclusion inclusion, boolean allowMultipleMatches)
    {
        // By default, do NOT delegate copy methods
        super(d, false);
        rootFilter = f;
        // and this is the currently active filter for root values
        _itemFilter = f;
        _filterContext = TokenFilterContext.createRootContext(f);
        _inclusion = inclusion;
        _allowMultipleMatches = allowMultipleMatches;
    }

    /*
    /**********************************************************
    /* Extended API
    /**********************************************************
     */

    public TokenFilter getFilter() { return rootFilter; }

    public JsonStreamContext getFilterContext() {
        return _filterContext;
    }
    
    /**
     * Accessor for finding number of matches, where specific token and sub-tree
     * starting (if structured type) are passed.
     */
    public int getMatchCount() {
        return _matchCount;
    }

    /*
    /**********************************************************
    /* Public API, accessors
    /**********************************************************
     */
    
    @Override
    public JsonStreamContext getOutputContext() {
        /* 11-Apr-2015, tatu: Choice is between pre- and post-filter context;
         *   let's expose post-filter context that correlates with the view
         *   of caller.
         */
        return _filterContext;
    }
    
    /*
    /**********************************************************
    /* Public API, write methods, structural
    /**********************************************************
     */
    
    @Override
    public void writeStartArray() throws IOException
    {
        // First things first: whole-sale skipping easy
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) { // include the whole sub-tree?
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray();
            return;
        }
        // Ok; regular checking state then
        _itemFilter = _filterContext.checkValue(_itemFilter);
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            _itemFilter = _itemFilter.filterStartArray();
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray();
        } else if (_itemFilter != null && _inclusion == Inclusion.INCLUDE_NON_NULL) {
            _checkParentPath(false /* isMatch */);
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray();
        } else {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, false);
        }
    }

    @SuppressWarnings("deprecation")
    @Override
    public void writeStartArray(int size) throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(size);
            return;
        }
        _itemFilter = _filterContext.checkValue(_itemFilter);
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            _itemFilter = _itemFilter.filterStartArray();
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(size);
        } else if (_itemFilter != null && _inclusion == Inclusion.INCLUDE_NON_NULL) {
            _checkParentPath(false /* isMatch */);
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(size);
        } else {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, false);
        }
    }

    @Override
    public void writeStartArray(Object forValue) throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(forValue);
            return;
        }
        _itemFilter = _filterContext.checkValue(_itemFilter);
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            _itemFilter = _itemFilter.filterStartArray();
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(forValue);
        } else {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, false);
        }
    }

    @Override
    public void writeStartArray(Object forValue, int size) throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(forValue, size);
            return;
        }
        _itemFilter = _filterContext.checkValue(_itemFilter);
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildArrayContext(null, false);
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            _itemFilter = _itemFilter.filterStartArray();
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, true);
            delegate.writeStartArray(forValue, size);
        } else {
            _filterContext = _filterContext.createChildArrayContext(_itemFilter, false);
        }
    }
    
    @Override
    public void writeEndArray() throws IOException
    {
        _filterContext = _filterContext.closeArray(delegate);

        if (_filterContext != null) {
            _itemFilter = _filterContext.getFilter();
        }
    }

    @Override
    public void writeStartObject() throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, true);
            delegate.writeStartObject();
            return;
        }

        TokenFilter f = _filterContext.checkValue(_itemFilter);
        if (f == null) {
            return;
        }
        
        if (f != TokenFilter.INCLUDE_ALL) {
            f = f.filterStartObject();
        }
        if (f == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildObjectContext(f, true);
            delegate.writeStartObject();
        } else if (f != null && _inclusion == Inclusion.INCLUDE_NON_NULL) {
            _checkParentPath(false /* isMatch */);
            _filterContext = _filterContext.createChildObjectContext(f, true);
            delegate.writeStartObject();
        } else { // filter out
            _filterContext = _filterContext.createChildObjectContext(f, false);
        }
    }

    @Override
    public void writeStartObject(Object forValue) throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, true);
            delegate.writeStartObject(forValue);
            return;
        }

        TokenFilter f = _filterContext.checkValue(_itemFilter);
        if (f == null) {
            return;
        }

        if (f != TokenFilter.INCLUDE_ALL) {
            f = f.filterStartObject();
        }
        if (f == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildObjectContext(f, true);
            delegate.writeStartObject(forValue);
        } else if (f != null && _inclusion == Inclusion.INCLUDE_NON_NULL) {
            _checkParentPath(false /* isMatch */);
            _filterContext = _filterContext.createChildObjectContext(f, true);
            delegate.writeStartObject(forValue);
        } else { // filter out
            _filterContext = _filterContext.createChildObjectContext(f, false);
        }
    }

    @Override
    public void writeStartObject(Object forValue, int size) throws IOException
    {
        if (_itemFilter == null) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, false);
            return;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            _filterContext = _filterContext.createChildObjectContext(_itemFilter, true);
            delegate.writeStartObject(forValue, size);
            return;
        }

        TokenFilter f = _filterContext.checkValue(_itemFilter);
        if (f == null) {
            return;
        }

        if (f != TokenFilter.INCLUDE_ALL) {
            f = f.filterStartObject();
        }
        if (f == TokenFilter.INCLUDE_ALL) {
            _checkParentPath();
            _filterContext = _filterContext.createChildObjectContext(f, true);
            delegate.writeStartObject(forValue, size);
        } else {
            _filterContext = _filterContext.createChildObjectContext(f, false);
        }
    }

    @Override
    public void writeEndObject() throws IOException
    {
        _filterContext = _filterContext.closeObject(delegate);
        if (_filterContext != null) {
            _itemFilter = _filterContext.getFilter();
        }
    }

    @Override
    public void writeFieldName(String name) throws IOException
    {
        TokenFilter state = _filterContext.setFieldName(name);
        if (state == null) {
            _itemFilter = null;
            return;
        }
        if (state == TokenFilter.INCLUDE_ALL) {
            _itemFilter = state;
            delegate.writeFieldName(name);
            return;
        }
        state = state.includeProperty(name);
        _itemFilter = state;
        if (state == TokenFilter.INCLUDE_ALL) {
            _checkPropertyParentPath();
        }
    }

    @Override
    public void writeFieldName(SerializableString name) throws IOException
    {
        TokenFilter state = _filterContext.setFieldName(name.getValue());
        if (state == null) {
            _itemFilter = null;
            return;
        }
        if (state == TokenFilter.INCLUDE_ALL) {
            _itemFilter = state;
            delegate.writeFieldName(name);
            return;
        }
        state = state.includeProperty(name.getValue());
        _itemFilter = state;
        if (state == TokenFilter.INCLUDE_ALL) {
            _checkPropertyParentPath();
        }
    }

    // 02-Dec-2019, tatu: Not sure what else to do... so use default impl from base class
    @Override
    public void writeFieldId(long id) throws IOException {
        writeFieldName(Long.toString(id));
    }

    /*
    /**********************************************************
    /* Public API, write methods, text/String values
    /**********************************************************
     */

    @Override
    public void writeString(String value) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeString(value)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeString(value);
    }

    @Override
    public void writeString(char[] text, int offset, int len) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            String value = new String(text, offset, len);
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeString(value)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeString(text, offset, len);
    }

    @Override
    public void writeString(SerializableString value) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeString(value.getValue())) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeString(value);
    }

    @Override
    public void writeString(Reader reader, int len) throws IOException {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                // [core#609]: do need to implement, but with 2.10.x TokenFilter no
                // useful method to call so will be mostly unfiltered
                if (!state.includeString(reader, len)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeString(reader, len);
    }

    @Override
    public void writeRawUTF8String(byte[] text, int offset, int length) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRawUTF8String(text, offset, length);
        }
    }

    @Override
    public void writeUTF8String(byte[] text, int offset, int length) throws IOException
    {
        // not exact match, but best we can do
        if (_checkRawValueWrite()) {
            delegate.writeUTF8String(text, offset, length);
        }
    }

    /*
    /**********************************************************
    /* Public API, write methods, binary/raw content
    /**********************************************************
     */

    @Override
    public void writeRaw(String text) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRaw(text);
        }
    }

    @Override
    public void writeRaw(String text, int offset, int len) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRaw(text, offset, len);
        }
    }

    @Override
    public void writeRaw(SerializableString text) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRaw(text);
        }
    }

    @Override
    public void writeRaw(char[] text, int offset, int len) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRaw(text, offset, len);
        }
    }

    @Override
    public void writeRaw(char c) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRaw(c);
        }
    }

    @Override
    public void writeRawValue(String text) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRawValue(text);
        }
    }

    @Override
    public void writeRawValue(String text, int offset, int len) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRawValue(text, offset, len);
        }
    }

    @Override
    public void writeRawValue(char[] text, int offset, int len) throws IOException
    {
        if (_checkRawValueWrite()) {
            delegate.writeRawValue(text, offset, len);
        }
    }

    @Override
    public void writeBinary(Base64Variant b64variant, byte[] data, int offset, int len) throws IOException
    {
        if (_checkBinaryWrite()) {
            delegate.writeBinary(b64variant, data, offset, len);
        }
    }

    @Override
    public int writeBinary(Base64Variant b64variant, InputStream data, int dataLength) throws IOException
    {
        if (_checkBinaryWrite()) {
            return delegate.writeBinary(b64variant, data, dataLength);
        }
        return -1;
    }

    /*
    /**********************************************************
    /* Public API, write methods, other value types
    /**********************************************************
     */

    @Override
    public void writeNumber(short v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(int v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(long v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(BigInteger v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(double v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(float v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(BigDecimal v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNumber(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(v);
    }

    @Override
    public void writeNumber(String encodedValue) throws IOException, UnsupportedOperationException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeRawValue()) { // close enough?
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(encodedValue);
    }

    @Override
    public void writeNumber(char[] encodedValueBuffer, int offset, int length) throws IOException, UnsupportedOperationException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeRawValue()) { // close enough?
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNumber(encodedValueBuffer, offset, length);
    }

    @Override
    public void writeBoolean(boolean v) throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeBoolean(v)) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeBoolean(v);
    }

    @Override
    public void writeNull() throws IOException
    {
        if (_itemFilter == null) {
            return;
        }
        if (_itemFilter != TokenFilter.INCLUDE_ALL) {
            TokenFilter state = _filterContext.checkValue(_itemFilter);
            if (state == null) {
                return;
            }
            if (state != TokenFilter.INCLUDE_ALL) {
                if (!state.includeNull()) {
                    return;
                }
            }
            _checkParentPath();
        }
        delegate.writeNull();
    }

    /*
    /**********************************************************
    /* Overridden field methods
    /**********************************************************
     */

    @Override
    public void writeOmittedField(String fieldName) throws IOException {
        // Hmmh. Not sure how this would work but...
        if (_itemFilter != null) {
            delegate.writeOmittedField(fieldName);
        }
    }
    
    /*
    /**********************************************************
    /* Public API, write methods, Native Ids
    /**********************************************************
     */

    // 25-Mar-2015, tatu: These are tricky as they sort of predate actual filtering calls.
    //   Let's try to use current state as a clue at least...
    
    @Override
    public void writeObjectId(Object id) throws IOException {
        if (_itemFilter != null) {
            delegate.writeObjectId(id);
        }
    }

    @Override
    public void writeObjectRef(Object id) throws IOException {
        if (_itemFilter != null) {
            delegate.writeObjectRef(id);
        }
    }
    
    @Override
    public void writeTypeId(Object id) throws IOException {
        if (_itemFilter != null) {
            delegate.writeTypeId(id);
        }
    }

    /*
    /**********************************************************
    /* Public API, write methods, serializing Java objects
    /**********************************************************
     */

    // Base class definitions for these seems correct to me, iff not directly delegating:

    /*
    @Override
    public void writeObject(Object pojo) throws IOException,JsonProcessingException {
        if (delegateCopyMethods) {
            delegate.writeObject(pojo);
            return;
        }
        // NOTE: copied from 
        if (pojo == null) {
            writeNull();
        } else {
            if (getCodec() != null) {
                getCodec().writeValue(this, pojo);
                return;
            }
            _writeSimpleObject(pojo);
        }
    }
    
    @Override
    public void writeTree(TreeNode rootNode) throws IOException {
        if (delegateCopyMethods) {
            delegate.writeTree(rootNode);
            return;
        }
        // As with 'writeObject()', we are not check if write would work
        if (rootNode == null) {
            writeNull();
        } else {
            if (getCodec() == null) {
                throw new IllegalStateException("No ObjectCodec defined");
            }
            getCodec().writeValue(this, rootNode);
        }
    }
    */

    /*
    /**********************************************************
    /* Public API, copy-through methods
    /**********************************************************
     */

    // Base class definitions for these seems correct to me, iff not directly delegating:

    /*
    @Override
    public void copyCurrentEvent(JsonParser jp) throws IOException {
        if (delegateCopyMethods) delegate.copyCurrentEvent(jp);
        else super.copyCurrentEvent(jp);
    }

    @Override
    public void copyCurrentStructure(JsonParser jp) throws IOException {
        if (delegateCopyMethods) delegate.copyCurrentStructure(jp);
        else super.copyCurrentStructure(jp);
    }
    */

    /*
    /**********************************************************
    /* Helper methods
    /**********************************************************
     */

    protected void _checkParentPath() throws IOException
    {
        _checkParentPath(true);
    }

    protected void  _checkParentPath(boolean isMatch) throws IOException
    {
        if (isMatch) {
            ++_matchCount;
        }
        // only need to construct path if parent wasn't written
        if (_inclusion == Inclusion.INCLUDE_ALL_AND_PATH) {
            _filterContext.writePath(delegate);
        } else if (_inclusion == Inclusion.INCLUDE_NON_NULL) {
            // path has already been written, except for maybe field name
            _filterContext.ensureFieldNameWritten(delegate);
        }
        // also: if no multiple matches desired, short-cut checks
        if (isMatch && !_allowMultipleMatches) {
            // Mark parents as "skip" so that further check calls are not made
            _filterContext.skipParentChecks();
        }
    }

    /**
     * Specialized variant of {@link #_checkParentPath} used when checking
     * parent for a property name to be included with value: rules are slightly
     * different.
     */
    protected void _checkPropertyParentPath() throws IOException
    {
        ++_matchCount;
        if (_inclusion == Inclusion.INCLUDE_ALL_AND_PATH) {
            _filterContext.writePath(delegate);
        } else if (_inclusion == Inclusion.INCLUDE_NON_NULL) {
            // path has already been written, except for maybe field name
            _filterContext.ensureFieldNameWritten(delegate);
        }

        // also: if no multiple matches desired, short-cut checks
        if (!_allowMultipleMatches) {
            // Mark parents as "skip" so that further check calls are not made
            _filterContext.skipParentChecks();
        }
    }
    
    protected boolean _checkBinaryWrite() throws IOException
    {
        if (_itemFilter == null) {
            return false;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            return true;
        }
        if (_itemFilter.includeBinary()) { // close enough?
            _checkParentPath();
            return true;
        }
        return false;
    }
    
    protected boolean _checkRawValueWrite() throws IOException
    {
        if (_itemFilter == null) {
            return false;
        }
        if (_itemFilter == TokenFilter.INCLUDE_ALL) {
            return true;
        }
        if (_itemFilter.includeRawValue()) { // close enough?
            _checkParentPath();
            return true;
        }
        return false;
    }
}

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

 

⇒ Download and Install Jackson Binary Package

⇐ What Is Jackson

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library