org.fxmisc.richtext.model.Paragraph Maven / Gradle / Ivy
package org.fxmisc.richtext.model;
import static org.fxmisc.richtext.model.TwoDimensional.Bias.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import javafx.scene.control.IndexRange;
import org.fxmisc.richtext.model.TwoDimensional.Position;
import org.reactfx.util.Tuple2;
import org.reactfx.util.Tuples;
/**
* One paragraph in the document that can itself be styled and which contains a list of styled segments.
*
*
* It corresponds to a single line when the
* text is not wrapped or spans multiple lines when the text is wrapped. A Paragraph
* contains of a list of {@link SEG} objects which make up the individual segments of the
* Paragraph. By providing a specific segment object and an associated
* {@link SegmentOps segment operations} object, all required data and the necessary
* operations on this data for a single segment can be provided.
*
*
* For more complex requirements (for example, when both text and images shall be part
* of the document), a different segment type must be provided. One should use something
* like {@code Either} for their segment type.
*
* Note that Paragraph is an immutable class - to modify a Paragraph, a new
* Paragraph object must be created. Paragraph itself contains some methods which
* take care of this, such as concat(), which appends some Paragraph to the current
* one and returns a new Paragraph.
*
* @param The type of the paragraph style.
* @param The type of the content segments in the paragraph (e.g. {@link String}).
* Every paragraph, even an empty paragraph, must have at least one {@link SEG} object
* (even if that {@link SEG} object itself represents an empty segment).
* @param The type of the style of individual segments.
*/
public final class Paragraph {
private static Tuple2, StyleSpans> decompose(List> list,
SegmentOps segmentOps) {
List segs = new ArrayList<>();
StyleSpansBuilder builder = new StyleSpansBuilder<>();
for (StyledSegment styledSegment : list) {
// attempt to merge differently-styled consecutive segments into one
if (segs.isEmpty()) {
segs.add(styledSegment.getSegment());
} else {
int lastIndex = segs.size() - 1;
SEG previousSeg = segs.get(lastIndex);
Optional merged = segmentOps.joinSeg(previousSeg, styledSegment.getSegment());
if (merged.isPresent()) {
segs.set(lastIndex, merged.get());
} else {
segs.add(styledSegment.getSegment());
}
}
// builder merges styles shared between consecutive different segments
builder.add(styledSegment.getStyle(), segmentOps.length(styledSegment.getSegment()));
}
return Tuples.t(segs, builder.create());
}
@SafeVarargs
private static List list(T head, T... tail) {
if(tail.length == 0) {
return Collections.singletonList(head);
} else {
ArrayList list = new ArrayList<>(1 + tail.length);
list.add(head);
Collections.addAll(list, tail);
return list;
}
}
private final List segments;
private final StyleSpans styles;
private final TwoLevelNavigator navigator;
private final PS paragraphStyle;
private final SegmentOps segmentOps;
/**
* Creates a paragraph using a list of styled segments
*/
public Paragraph(PS paragraphStyle, SegmentOps segmentOps, List> styledSegments) {
this(paragraphStyle, segmentOps, decompose(styledSegments, segmentOps));
}
private Paragraph(PS paragraphStyle, SegmentOps segmentOps, Tuple2, StyleSpans> decomposedList) {
this(paragraphStyle, segmentOps, decomposedList._1, decomposedList._2);
}
/**
* Creates a paragraph that has only one segment that has the same given style throughout.
*/
public Paragraph(PS paragraphStyle, SegmentOps segmentOps, SEG segment, S style) {
this(paragraphStyle, segmentOps, segment, StyleSpans.singleton(style, segmentOps.length(segment)));
}
/**
* Creates a paragraph that has only one segment but a number of different styles throughout that segment
*/
public Paragraph(PS paragraphStyle, SegmentOps segmentOps, SEG segment, StyleSpans styles) {
this(paragraphStyle, segmentOps, Collections.singletonList(segment), styles);
}
/**
* Creates a paragraph that has multiple segments with multiple styles throughout those segments
*/
public Paragraph(PS paragraphStyle, SegmentOps segmentOps, List segments, StyleSpans styles) {
if (segments.isEmpty()) {
throw new IllegalArgumentException("Cannot construct a Paragraph with an empty list of segments");
}
if (styles.getSpanCount() == 0) {
throw new IllegalArgumentException(
"Cannot construct a Paragraph with StyleSpans object that contains no StyleSpan objects"
);
}
this.segmentOps = segmentOps;
this.segments = segments;
this.styles = styles;
this.paragraphStyle = paragraphStyle;
navigator = new TwoLevelNavigator(segments::size,
i -> segmentOps.length(segments.get(i))
);
}
private List> styledSegments = null;
/**
* Since the segments and styles in a paragraph are stored separate from another, combines these two collections
* into a single collection where each segment and its corresponding style are grouped into the same object.
* Essentially, returns {@code List>}.
*/
public List> getStyledSegments() {
if (styledSegments == null) {
if (segments.size() == 1 && styles.getSpanCount() == 1) {
styledSegments = Collections.singletonList(
new StyledSegment<>(segments.get(0), styles.getStyleSpan(0).getStyle())
);
} else {
styledSegments = createStyledSegments();
}
}
return styledSegments;
}
public List getSegments() {
return Collections.unmodifiableList(segments);
}
public PS getParagraphStyle() {
return paragraphStyle;
}
private int length = -1;
public int length() {
if(length == -1) {
length = segments.stream().mapToInt(segmentOps::length).sum();
}
return length;
}
public char charAt(int index) {
Position pos = navigator.offsetToPosition(index, Forward);
return segmentOps.charAt(segments.get(pos.getMajor()), pos.getMinor());
}
public String substring(int from, int to) {
return getText().substring(from, Math.min(to, length()));
}
public String substring(int from) {
return getText().substring(from);
}
/**
* Concatenates this paragraph with the given paragraph {@code p}.
* The paragraph style of the result will be that of this paragraph,
* unless this paragraph is empty and {@code p} is non-empty, in which
* case the paragraph style of the result will be that of {@code p}.
*/
public Paragraph concat(Paragraph p) {
if(p.length() == 0) {
return this;
}
if(length() == 0) {
return p;
}
List updatedSegs;
SEG leftSeg = segments.get(segments.size() - 1);
SEG rightSeg = p.segments.get(0);
Optional joined = segmentOps.joinSeg(leftSeg, rightSeg);
if(joined.isPresent()) {
SEG segment = joined.get();
updatedSegs = new ArrayList<>(segments.size() + p.segments.size() - 1);
updatedSegs.addAll(segments.subList(0, segments.size()-1));
updatedSegs.add(segment);
updatedSegs.addAll(p.segments.subList(1, p.segments.size()));
} else {
updatedSegs = new ArrayList<>(segments.size() + p.segments.size());
updatedSegs.addAll(segments);
updatedSegs.addAll(p.segments);
}
StyleSpans updatedStyles;
StyleSpan leftSpan = styles.getStyleSpan(styles.getSpanCount() - 1);
StyleSpan rightSpan = p.styles.getStyleSpan(0);
Optional merge = segmentOps.joinStyle(leftSpan.getStyle(), rightSpan.getStyle());
if (merge.isPresent()) {
int startOfMerge = styles.position(styles.getSpanCount() - 1, 0).toOffset();
StyleSpans updatedLeftSpan = styles.subView(0, startOfMerge);
int endOfMerge = p.styles.position(1, 0).toOffset();
StyleSpans updatedRightSpan = p.styles.subView(endOfMerge, p.styles.length());
updatedStyles = updatedLeftSpan
.append(merge.get(), leftSpan.getLength() + rightSpan.getLength())
.concat(updatedRightSpan);
} else {
updatedStyles = styles.concat(p.styles);
}
return new Paragraph<>(paragraphStyle, segmentOps, updatedSegs, updatedStyles);
}
/**
* Similar to {@link #concat(Paragraph)}, except in case both paragraphs
* are empty, the result's paragraph style will be that of the argument.
*/
Paragraph concatR(Paragraph that) {
return this.length() == 0 && that.length() == 0
? that
: concat(that);
}
public Paragraph subSequence(int start, int end) {
return trim(end).subSequence(start);
}
public Paragraph trim(int length) {
if(length >= length()) {
return this;
} else {
Position pos = navigator.offsetToPosition(length, Backward);
int segIdx = pos.getMajor();
List segs = new ArrayList<>(segIdx + 1);
segs.addAll(segments.subList(0, segIdx));
segs.add(segmentOps.subSequence(segments.get(segIdx), 0, pos.getMinor()));
if (segs.isEmpty()) {
segs.add(segmentOps.createEmptySeg());
}
return new Paragraph<>(paragraphStyle, segmentOps, segs, styles.subView(0, length));
}
}
public Paragraph subSequence(int start) {
if(start < 0) {
throw new IllegalArgumentException("start must not be negative (was: " + start + ")");
} else if(start == 0) {
return this;
} else if (start == length()) {
// in case one is using EitherOps, force the empty segment
// to use the left ops' default empty seg, not the right one's empty seg
return new Paragraph<>(paragraphStyle, segmentOps, segmentOps.createEmptySeg(), styles.subView(start,start));
} else if(start < length()) {
Position pos = navigator.offsetToPosition(start, Forward);
int segIdx = pos.getMajor();
List segs = new ArrayList<>(segments.size() - segIdx);
segs.add(segmentOps.subSequence(segments.get(segIdx), pos.getMinor()));
segs.addAll(segments.subList(segIdx + 1, segments.size()));
if (segs.isEmpty()) {
segs.add(segmentOps.createEmptySeg());
}
return new Paragraph<>(paragraphStyle, segmentOps, segs, styles.subView(start, styles.length()));
} else {
throw new IndexOutOfBoundsException(start + " not in [0, " + length() + "]");
}
}
public Paragraph delete(int start, int end) {
return trim(start).concat(subSequence(end));
}
/**
* Restyles every segment in the paragraph to have the given style.
*
* Note: because Paragraph is immutable, this method returns a new Paragraph.
* The current Paragraph is unchanged.
*
* @param style The new style for each segment in the paragraph.
* @return The new paragraph with the restyled segments.
*/
public Paragraph restyle(S style) {
return new Paragraph<>(paragraphStyle, segmentOps, segments, StyleSpans.singleton(style, length()));
}
public Paragraph restyle(int from, int to, S style) {
if(from >= length()) {
return this;
} else {
StyleSpans left = styles.subView(0, from);
StyleSpans right = styles.subView(to, length());
StyleSpans updatedStyles = left.append(style, to - from).concat(right);
return new Paragraph<>(paragraphStyle, segmentOps, segments, updatedStyles);
}
}
public Paragraph restyle(int from, StyleSpans styleSpans) {
int len = styleSpans.length();
if(styleSpans.equals(getStyleSpans(from, from + len)) || styleSpans.getSpanCount() == 0) {
return this;
}
if(length() == 0) {
return new Paragraph<>(paragraphStyle, segmentOps, segments, (StyleSpans) styleSpans);
}
StyleSpans left = styles.subView(0, from);
StyleSpans right = styles.subView(from + len, length());
// type issue with concat
StyleSpans castedSpans = (StyleSpans) styleSpans;
StyleSpans updatedStyles = left.concat(castedSpans).concat(right);
return new Paragraph<>(paragraphStyle, segmentOps, segments, updatedStyles);
}
/**
* Creates a new Paragraph which has the same contents as the current Paragraph,
* but the given paragraph style.
*
* Note that because Paragraph is immutable, a new Paragraph is returned.
* Despite the setX name, the current object is unchanged.
*
* @param paragraphStyle The new paragraph style
* @return A new paragraph with the same segment contents, but a new paragraph style.
*/
public Paragraph setParagraphStyle(PS paragraphStyle) {
return new Paragraph<>(paragraphStyle, segmentOps, segments, styles);
}
/**
* Returns the style of character with the given index.
* If {@code charIdx < 0}, returns the style at the beginning of this paragraph.
* If {@code charIdx >= this.length()}, returns the style at the end of this paragraph.
*/
public S getStyleOfChar(int charIdx) {
if(charIdx < 0) {
return styles.getStyleSpan(0).getStyle();
}
Position pos = styles.offsetToPosition(charIdx, Forward);
return styles.getStyleSpan(pos.getMajor()).getStyle();
}
/**
* Returns the style at the given position. That is the style of the
* character immediately preceding {@code position}. If {@code position}
* is 0, then the style of the first character (index 0) in this paragraph
* is returned. If this paragraph is empty, then some style previously used
* in this paragraph is returned.
* If {@code position > this.length()}, then it is equivalent to
* {@code position == this.length()}.
*
* In other words, {@code getStyleAtPosition(p)} is equivalent to
* {@code getStyleOfChar(p-1)}.
*/
public S getStyleAtPosition(int position) {
if(position < 0) {
throw new IllegalArgumentException("Paragraph position cannot be negative (" + position + ")");
}
Position pos = styles.offsetToPosition(position, Backward);
return styles.getStyleSpan(pos.getMajor()).getStyle();
}
/**
* Returns the range of homogeneous style that includes the given position.
* If {@code position} points to a boundary between two styled ranges,
* then the range preceding {@code position} is returned.
*/
public IndexRange getStyleRangeAtPosition(int position) {
Position pos = styles.offsetToPosition(position, Backward);
int start = position - pos.getMinor();
int end = start + styles.getStyleSpan(pos.getMajor()).getLength();
return new IndexRange(start, end);
}
public StyleSpans getStyleSpans() {
return styles;
}
public StyleSpans getStyleSpans(int from, int to) {
return styles.subView(from, to);
}
private String text = null;
/**
* Returns the plain text content of this paragraph,
* not including the line terminator.
*/
public String getText() {
if(text == null) {
StringBuilder sb = new StringBuilder(length());
for(SEG seg: segments)
sb.append(segmentOps.getText(seg));
text = sb.toString();
}
return text;
}
@Override
public String toString() {
return
"Par[" + paragraphStyle + "; " +
getStyledSegments().stream().map(Object::toString)
.reduce((s1, s2) -> s1 + ", " + s2).orElse("") +
"]";
}
/**
* Two paragraphs are defined to be equal if they have the same style (as defined by
* PS.equals) and the same list of segments (as defined by SEG.equals).
*/
@Override
public boolean equals(Object other) {
if(other instanceof Paragraph) {
Paragraph that = (Paragraph) other;
return Objects.equals(this.paragraphStyle, that.paragraphStyle)
&& Objects.equals(this.segments, that.segments)
&& Objects.equals(this.styles, that.styles);
} else {
return false;
}
}
@Override
public int hashCode() {
return Objects.hash(paragraphStyle, segments, styles);
}
private List> createStyledSegments() {
List> styledSegments = new LinkedList<>();
Iterator segIterator = segments.iterator();
Iterator> styleIterator = styles.iterator();
SEG segCurrent = segIterator.next();
StyleSpan styleCurrent = styleIterator.next();
int segOffset = 0, styleOffset = 0;
boolean finished = false;
while (!finished) {
int segLength = segmentOps.length(segCurrent) - segOffset;
int styleLength = styleCurrent.getLength() - styleOffset;
if (segLength < styleLength) {
SEG splitSeg = segmentOps.subSequence(segCurrent, segOffset);
styledSegments.add(new StyledSegment<>(splitSeg, styleCurrent.getStyle()));
segCurrent = segIterator.next();
segOffset = 0;
styleOffset += segLength;
} else if (styleLength < segLength) {
SEG splitSeg = segmentOps.subSequence(segCurrent, segOffset, segOffset + styleLength);
styledSegments.add(new StyledSegment<>(splitSeg, styleCurrent.getStyle()));
styleCurrent = styleIterator.next();
styleOffset = 0;
segOffset += styleLength;
} else {
SEG splitSeg = segmentOps.subSequence(segCurrent, segOffset, segOffset + styleLength);
styledSegments.add(new StyledSegment<>(splitSeg, styleCurrent.getStyle()));
if (segIterator.hasNext() && styleIterator.hasNext()) {
segCurrent = segIterator.next();
segOffset = 0;
styleCurrent = styleIterator.next();
styleOffset = 0;
} else {
finished = true;
}
}
}
return styledSegments;
}
}