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package org.protege.editor.owl.ui.renderer.layout;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* Author: Matthew Horridge
* Stanford University
* Bio-Medical Informatics Research Group
* Date: 01/11/2011
*
* Describes spans of text.
*/
public class Span {
private int startIndex = -1;
private int endIndex = -1;
/**
* Desribes a span over a String.
* @param startIndex The start index of the span in the String
* @param endIndex The end index of the span in the String. The end index is exclusive in that the substring
* denoted by this span is up to but not including the end index. For example, given the string "abc" the Span
* with a start index of 0 and an end index of 2 describes the substring "ab".
*/
public Span(int startIndex, int endIndex) {
this.startIndex = startIndex;
this.endIndex = endIndex;
}
/**
* Gets the start index of this span.
* @return The start index.
*/
public int getStartIndex() {
return startIndex;
}
/**
* Gets the end index of this span.
* @return The end index.
*/
public int getEndIndex() {
return endIndex;
}
/**
* Determines if this span intersects with another span. A span C intersects with a span D if the start index of
* C is less than the end index of D, and the end index of D is greate than the start index of C + 1. This implies
* that the intersection is non-empty.
* @param span The other span to test for intersection with.
* @return true if this span intersects with the other span, otherwise false.
*/
public boolean intersectsWith(Span span) {
return span.startIndex < endIndex && span.endIndex > startIndex + 1;
}
@Override
public String toString() {
return "Span(" + startIndex + ", " + endIndex + ")";
}
/**
* Gets the length of this span. This is equivalent to the end index minus the start index.
* @return The length of this span.
*/
public int getLength() {
return endIndex - startIndex;
}
/**
* Determines if this span is empty. A span is empty if its start index is equal to its end index.
*/
public boolean isEmpty() {
return endIndex <= startIndex;
}
/**
* Gets a span which is the same as this span but with (1) a start index (specified by the from parameter) that is
* greater than or equal to the start index of this span, and an end index is less than the end index of this span,
* and (2) an end index (specified by the to parameter) that is greater or equal to the start index of this span
* but less than the end index of this span.
* @param from The new crop index which specifies the start of the cropped span. If from is less than the start
* index of this span then it is set to the start index of this span.
* @param to The new crop index which specified the end of the cropped span. If to is greater than the end index
* of this span then it is capped to the end index of this span.
* @return The new span with a start index of from, and an end index of to.
*/
public Span crop(int from, int to) {
int croppedFrom = from > startIndex ? from : startIndex;
int croppedTo = to < endIndex ? to : endIndex;
return new Span(croppedFrom, croppedTo);
}
public List split(List positions) {
List stack = new ArrayList<>();
stack.add(0, this);
for(int position : positions) {
if(position > startIndex && position < endIndex) {
Span currentSpan = stack.get(0);
if(position >= currentSpan.startIndex && position < currentSpan.endIndex) {
stack.remove(0);
stack.add(0, new Span(currentSpan.startIndex, position));
stack.add(0, new Span(position, currentSpan.endIndex));
}
else {
break;
}
}
}
Collections.reverse(stack);
return stack;
}
}