class ContentNode extends Node implements Content {
    protected List<BasedSequence> lineSegments = BasedSequence.EMPTY_LIST;

    public ContentNode() {

    }

    public ContentNode(@NotNull BasedSequence chars) {
        super(chars);
    }

    public ContentNode(@NotNull BasedSequence chars, @NotNull List<BasedSequence> lineSegments) {
        super(chars);
        this.lineSegments = lineSegments;
    }

    public ContentNode(@NotNull List<BasedSequence> lineSegments) {
        this(getSpanningChars(lineSegments), lineSegments);
    }

    public ContentNode(@NotNull BlockContent blockContent) {
        this(blockContent.getSpanningChars(), blockContent.getLines());
    }

    public void setContent(@NotNull BasedSequence chars, @NotNull List<BasedSequence> lineSegments) {
        setChars(chars);
        this.lineSegments = lineSegments;
    }

    public void setContent(@NotNull List<BasedSequence> lineSegments) {
        this.lineSegments = lineSegments;
        setChars(getSpanningChars());
    }

    public void setContent(@NotNull BlockContent blockContent) {
        setChars(blockContent.getSpanningChars());
        this.lineSegments = blockContent.getLines();
    }

    @Override
    public @NotNull BasedSequence getSpanningChars() {
        return getSpanningChars(lineSegments);
    }

    private static @NotNull BasedSequence getSpanningChars(@NotNull List<BasedSequence> lineSegments) {
        return lineSegments.isEmpty() ? BasedSequence.NULL : lineSegments.get(0).baseSubSequence(lineSegments.get(0).getStartOffset(), lineSegments.get(lineSegments.size() - 1).getEndOffset());
    }

    @Override
    public int getLineCount() {
        return lineSegments.size();
    }

    @NotNull
    @Override
    public BasedSequence getLineChars(int index) {
        return lineSegments.get(index);
    }

    @NotNull
    @Override
    public List<BasedSequence> getContentLines() {
        return lineSegments;
    }

    @NotNull
    @Override
    public List<BasedSequence> getContentLines(int startLine, int endLine) {
        return lineSegments.subList(startLine, endLine);
    }

    @NotNull
    @Override
    public BasedSequence getContentChars() {
        return lineSegments.isEmpty() ? BasedSequence.NULL : SegmentedSequence.create(lineSegments.get(0), lineSegments);
    }

    @NotNull
    @Override
    public BasedSequence getContentChars(int startLine, int endLine) {
        return lineSegments.isEmpty() ? BasedSequence.NULL : SegmentedSequence.create(lineSegments.get(0), getContentLines(startLine, endLine));
    }

    public void setContentLines(@NotNull List<BasedSequence> contentLines) {
        this.lineSegments = contentLines;
    }

    public void setContentLine(int lineIndex, @NotNull BasedSequence contentLine) {<FILL_FUNCTION_BODY>}
}

        ArrayList<BasedSequence> lines = new ArrayList<>(lineSegments);
        lines.set(lineIndex, contentLine);
        this.lineSegments = lines;
        setCharsFromContent();
    
<methods>public void <init>() ,public void <init>(@NotNull BasedSequence) ,public void appendChain(@NotNull Node) ,public void appendChild(com.vladsch.flexmark.util.ast.Node) ,public static void astChars(@NotNull StringBuilder, @NotNull CharSequence, @NotNull String) ,public void astExtraChars(@NotNull StringBuilder) ,public void astString(@NotNull StringBuilder, boolean) ,public com.vladsch.flexmark.util.sequence.BasedSequence baseSubSequence(int, int) ,public com.vladsch.flexmark.util.sequence.BasedSequence baseSubSequence(int) ,public transient int countAncestorsOfType(@NotNull Class<?> []) ,public transient int countDirectAncestorsOfType(@Nullable Class<?>, @NotNull Class<?> []) ,public static void delimitedSegmentSpan(@NotNull StringBuilder, @NotNull BasedSequence, @NotNull BasedSequence, @NotNull BasedSequence, @NotNull String) ,public static void delimitedSegmentSpanChars(@NotNull StringBuilder, @NotNull BasedSequence, @NotNull BasedSequence, @NotNull BasedSequence, @NotNull String) ,public int endOfLine(int) ,public void extractChainTo(@NotNull Node) ,public void extractToFirstInChain(@NotNull Node) ,public transient @Nullable Node getAncestorOfType(@NotNull Class<?> []) ,public void getAstExtra(@NotNull StringBuilder) ,public com.vladsch.flexmark.util.sequence.BasedSequence getBaseSequence() ,public @NotNull Node getBlankLineSibling() ,public @NotNull BasedSequence getChars() ,public @NotNull BasedSequence getCharsFromSegments() ,public com.vladsch.flexmark.util.sequence.BasedSequence getChildChars() ,public @NotNull ReversiblePeekingIterator<Node> getChildIterator() ,public transient @Nullable Node getChildOfType(@NotNull Class<?> []) ,public @NotNull ReversiblePeekingIterable<Node> getChildren() ,public @NotNull ReversiblePeekingIterable<Node> getDescendants() ,public @NotNull Document getDocument() ,public com.vladsch.flexmark.util.sequence.BasedSequence getEmptyPrefix() ,public com.vladsch.flexmark.util.sequence.BasedSequence getEmptySuffix() ,public int getEndLineNumber() ,public int getEndOfLine() ,public int getEndOffset() ,public com.vladsch.flexmark.util.sequence.BasedSequence getExactChildChars() ,public @Nullable Node getFirstChild() ,public transient @Nullable Node getFirstChildAny(@NotNull Class<?> []) ,public transient @Nullable Node getFirstChildAnyNot(@NotNull Class<?> []) ,public @NotNull Node getFirstInChain() ,public @Nullable Node getGrandParent() ,public @Nullable Node getLastBlankLineChild() ,public @Nullable Node getLastChild() ,public transient @Nullable Node getLastChildAny(@NotNull Class<?> []) ,public transient @Nullable Node getLastChildAnyNot(@NotNull Class<?> []) ,public @NotNull Node getLastInChain() ,public static @NotNull BasedSequence getLeadSegment(@NotNull BasedSequence []) ,public Pair<java.lang.Integer,java.lang.Integer> getLineColumnAtEnd() ,public int getLineNumber() ,public @Nullable Node getNext() ,public transient @Nullable Node getNextAny(@NotNull Class<?> []) ,public transient @Nullable Node getNextAnyNot(@NotNull Class<?> []) ,public @NotNull String getNodeName() ,public static transient int getNodeOfTypeIndex(@NotNull Node, @NotNull Class<?> []) ,public transient int getNodeOfTypeIndex(@NotNull Class<?> []) ,public @Nullable Node getOldestAncestorOfTypeAfter(@NotNull Class<?>, @NotNull Class<?>) ,public @Nullable Node getParent() ,public @Nullable Node getPrevious() ,public transient @Nullable Node getPreviousAny(@NotNull Class<?> []) ,public transient @Nullable Node getPreviousAnyNot(@NotNull Class<?> []) ,public @NotNull ReversiblePeekingIterator<Node> getReversedChildIterator() ,public @NotNull ReversiblePeekingIterable<Node> getReversedChildren() ,public @NotNull ReversiblePeekingIterable<Node> getReversedDescendants() ,public abstract @NotNull BasedSequence [] getSegments() ,public @NotNull BasedSequence [] getSegmentsForChars() ,public com.vladsch.flexmark.util.sequence.Range getSourceRange() ,public int getStartLineNumber() ,public int getStartOfLine() ,public int getStartOffset() ,public int getTextLength() ,public static @NotNull BasedSequence getTrailSegment(com.vladsch.flexmark.util.sequence.BasedSequence[]) ,public boolean hasChildren() ,public boolean hasOrMoreChildren(int) ,public void insertAfter(@NotNull Node) ,public void insertBefore(com.vladsch.flexmark.util.ast.Node) ,public void insertChainAfter(@NotNull Node) ,public void insertChainBefore(@NotNull Node) ,public transient boolean isOrDescendantOfType(@NotNull Class<?> []) ,public Pair<java.lang.Integer,java.lang.Integer> lineColumnAtIndex(int) ,public Pair<java.lang.Integer,java.lang.Integer> lineColumnAtStart() ,public void moveTrailingBlankLines() ,public void prependChild(@NotNull Node) ,public void removeChildren() ,public static void segmentSpan(@NotNull StringBuilder, int, int, @Nullable String) ,public static void segmentSpan(@NotNull StringBuilder, @NotNull BasedSequence, @Nullable String) ,public static void segmentSpanChars(@NotNull StringBuilder, int, int, @Nullable String, @NotNull String) ,public static void segmentSpanChars(@NotNull StringBuilder, int, int, @Nullable String, @NotNull String, @NotNull String, @NotNull String) ,public static void segmentSpanChars(@NotNull StringBuilder, @NotNull BasedSequence, @NotNull String) ,public static void segmentSpanCharsToVisible(@NotNull StringBuilder, @NotNull BasedSequence, @NotNull String) ,public void setChars(@NotNull BasedSequence) ,public void setCharsFromContent() ,public void setCharsFromContentOnly() ,public void setCharsFromSegments() ,public static transient @NotNull BasedSequence spanningChars(com.vladsch.flexmark.util.sequence.BasedSequence[]) ,public int startOfLine(int) ,public void takeChildren(@NotNull Node) ,public @NotNull String toAstString(boolean) ,public static @NotNull String toSegmentSpan(@NotNull BasedSequence, @Nullable String) ,public java.lang.String toString() ,public void unlink() <variables>public static final AstNode<com.vladsch.flexmark.util.ast.Node> AST_ADAPTER,public static final com.vladsch.flexmark.util.sequence.BasedSequence[] EMPTY_SEGMENTS,public static final java.lang.String SPLICE,private @NotNull BasedSequence chars,@Nullable Node firstChild,private @Nullable Node lastChild,@Nullable Node next,private @Nullable Node parent,private @Nullable Node prev