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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package opennlp.tools.util;
import java.io.Serializable;
import java.util.Objects;
/**
* Class for storing start and end integer offsets.
*
*/
public class Span implements Comparable, Serializable {
private final int start;
private final int end;
private final double prob;//default is 0
private final String type;
/**
* Initializes a new Span Object. Sets the prob to 0 as default.
*
* @param s start of span.
* @param e end of span, which is +1 more than the last element in the span.
* @param type the type of the span
*/
public Span(int s, int e, String type) {
this(s, e, type, 0d);
}
/**
* Initializes a new Span Object.
*
* @param s start of span.
* @param e end of span, which is +1 more than the last element in the span.
* @param type the type of the span
* @param prob probability of span.
*/
public Span(int s, int e, String type, double prob) {
if (s < 0) {
throw new IllegalArgumentException("start index must be zero or greater: " + s);
}
if (e < 0) {
throw new IllegalArgumentException("end index must be zero or greater: " + e);
}
if (s > e) {
throw new IllegalArgumentException("start index must not be larger than end index: "
+ "start=" + s + ", end=" + e);
}
start = s;
end = e;
this.prob = prob;
this.type = type;
}
/**
* Initializes a new Span Object. Sets the prob to 0 as default
*
* @param s start of span.
* @param e end of span.
*/
public Span(int s, int e) {
this(s, e, null, 0d);
}
/**
*
* @param s the start of the span (the token index, not the char index)
* @param e the end of the span (the token index, not the char index)
* @param prob
*/
public Span(int s, int e, double prob) {
this(s, e, null, prob);
}
/**
* Initializes a new Span object with an existing Span which is shifted by an
* offset.
*
* @param span
* @param offset
*/
public Span(Span span, int offset) {
this(span.start + offset, span.end + offset, span.getType(), span.getProb());
}
/**
* Creates a new immutable span based on an existing span, where the existing span did not include the prob
* @param span the span that has no prob or the prob is incorrect and a new Span must be generated
* @param prob the probability of the span
*/
public Span(Span span, double prob) {
this(span.start, span.end, span.getType(), prob);
}
/**
* Return the start of a span.
*
* @return the start of a span.
*
*/
public int getStart() {
return start;
}
/**
* Return the end of a span.
*
* Note: that the returned index is one past the actual end of the span in the
* text, or the first element past the end of the span.
*
* @return the end of a span.
*
*/
public int getEnd() {
return end;
}
/**
* Retrieves the type of the span.
*
* @return the type or null if not set
*/
public String getType() {
return type;
}
/**
* Returns the length of this span.
*
* @return the length of the span.
*/
public int length() {
return end - start;
}
/**
* Returns true if the specified span is contained by this span. Identical
* spans are considered to contain each other.
*
* @param s The span to compare with this span.
*
* @return true is the specified span is contained by this span; false otherwise.
*/
public boolean contains(Span s) {
return start <= s.getStart() && s.getEnd() <= end;
}
/**
* Returns true if the specified index is contained inside this span. An index
* with the value of end is considered outside the span.
*
* @param index the index to test with this span.
*
* @return true if the span contains this specified index; false otherwise.
*/
public boolean contains(int index) {
return start <= index && index < end;
}
/**
* Returns true if the specified span is the begin of this span and the
* specified span is contained in this span.
*
* @param s The span to compare with this span.
*
* @return true if the specified span starts with this span and is contained
* in this span; false otherwise
*/
public boolean startsWith(Span s) {
return getStart() == s.getStart() && contains(s);
}
/**
* Returns true if the specified span intersects with this span.
*
* @param s The span to compare with this span.
*
* @return true is the spans overlap; false otherwise.
*/
public boolean intersects(Span s) {
int sstart = s.getStart();
//either s's start is in this or this' start is in s
return this.contains(s) || s.contains(this)
|| getStart() <= sstart && sstart < getEnd()
|| sstart <= getStart() && getStart() < s.getEnd();
}
/**
* Returns true is the specified span crosses this span.
*
* @param s The span to compare with this span.
*
* @return true is the specified span overlaps this span and contains a
* non-overlapping section; false otherwise.
*/
public boolean crosses(Span s) {
int sstart = s.getStart();
//either s's start is in this or this' start is in s
return !this.contains(s) && !s.contains(this)
&& (getStart() <= sstart && sstart < getEnd()
|| sstart <= getStart() && getStart() < s.getEnd());
}
/**
* Retrieves the string covered by the current span of the specified text.
*
* @param text
*
* @return the substring covered by the current span
*/
public CharSequence getCoveredText(CharSequence text) {
if (getEnd() > text.length()) {
throw new IllegalArgumentException("The span " + toString()
+ " is outside the given text which has length " + text.length() + "!");
}
return text.subSequence(getStart(), getEnd());
}
/**
* Return a copy of this span with leading and trailing white spaces removed.
*
* @param text
*
* @return the trimmed span or the same object if already trimmed
*/
public Span trim(CharSequence text) {
int newStartOffset = getStart();
for (int i = getStart(); i < getEnd() && StringUtil.isWhitespace(text.charAt(i)); i++) {
newStartOffset++;
}
int newEndOffset = getEnd();
for (int i = getEnd(); i > getStart() && StringUtil.isWhitespace(text.charAt(i - 1)); i--) {
newEndOffset--;
}
if (newStartOffset == getStart() && newEndOffset == getEnd()) {
return this;
} else if (newStartOffset > newEndOffset) {
return new Span(getStart(), getStart(), getType());
} else {
return new Span(newStartOffset, newEndOffset, getType());
}
}
/**
* Compares the specified span to the current span.
*/
public int compareTo(Span s) {
if (getStart() < s.getStart()) {
return -1;
} else if (getStart() == s.getStart()) {
if (getEnd() > s.getEnd()) {
return -1;
} else if (getEnd() < s.getEnd()) {
return 1;
} else {
// compare the type
if (getType() == null && s.getType() == null) {
return 0;
} else if (getType() != null && s.getType() != null) {
// use type lexicography order
return getType().compareTo(s.getType());
} else if (getType() != null) {
return -1;
}
return 1;
}
} else {
return 1;
}
}
/**
* Generates a hash code of the current span.
*/
@Override
public int hashCode() {
return Objects.hash(getStart(), getEnd(), getType());
}
/**
* Checks if the specified span is equal to the current span.
*/
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (o instanceof Span) {
Span s = (Span) o;
return getStart() == s.getStart() && getEnd() == s.getEnd()
&& Objects.equals(getType(), s.getType());
}
return false;
}
/**
* Generates a human readable string.
*/
@Override
public String toString() {
StringBuilder toStringBuffer = new StringBuilder(15);
toStringBuffer.append("[");
toStringBuffer.append(getStart());
toStringBuffer.append("..");
toStringBuffer.append(getEnd());
toStringBuffer.append(")");
if (getType() != null) {
toStringBuffer.append(" ");
toStringBuffer.append(getType());
}
return toStringBuffer.toString();
}
/**
* Converts an array of {@link Span}s to an array of {@link String}s.
*
* @param spans
* @param s
* @return the strings
*/
public static String[] spansToStrings(Span[] spans, CharSequence s) {
String[] tokens = new String[spans.length];
for (int si = 0, sl = spans.length; si < sl; si++) {
tokens[si] = spans[si].getCoveredText(s).toString();
}
return tokens;
}
public static String[] spansToStrings(Span[] spans, String[] tokens) {
String[] chunks = new String[spans.length];
StringBuilder cb = new StringBuilder();
for (int si = 0, sl = spans.length; si < sl; si++) {
cb.setLength(0);
for (int ti = spans[si].getStart(); ti < spans[si].getEnd(); ti++) {
cb.append(tokens[ti]).append(" ");
}
chunks[si] = cb.substring(0, cb.length() - 1);
}
return chunks;
}
public double getProb() {
return prob;
}
}