link footnotes with heuristics

grobid-core/src/main/java/org/grobid/core/data/Footnote.java

@@ -0,0 +1,90 @@
+package org.grobid.core.data;
+
+import org.grobid.core.layout.LayoutToken;
+import org.grobid.core.layout.Page;
+
+import java.util.List;
+
+import static com.google.common.collect.Iterables.getLast;
+
+public class Footnote {
+
+    private int number;
+
+    private List<LayoutToken> tokens;
+
+    private String text;
+
+    private int offsetStartInPage;
+
+    private boolean ignored = false;
+
+    public Footnote() {
+    }
+
+    public Footnote(int number, List<LayoutToken> tokens, String text) {
+        this.number = number;
+        this.tokens = tokens;
+        this.text = text;
+    }
+
+    public Footnote(int number, List<LayoutToken> tokens, String text, int offsetStartInPage) {
+        this.number = number;
+        this.tokens = tokens;
+        this.text = text;
+        this.offsetStartInPage = offsetStartInPage;
+    }
+
+    public Footnote(int number, List<LayoutToken> tokens) {
+        this.number = number;
+        this.tokens = tokens;
+    }
+
+    public int getOffsetStartInPage() {
+        return offsetStartInPage;
+    }
+
+    public void setOffsetStartInPage(int offsetStartInPage) {
+        this.offsetStartInPage = offsetStartInPage;
+    }
+
+    public int getPageNumber() {
+        return tokens.get(0).getPage();
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public List<LayoutToken> getTokens() {
+        return tokens;
+    }
+
+    public void setTokens(List<LayoutToken> tokens) {
+        this.tokens = tokens;
+    }
+
+    public int getNumber() {
+        return number;
+    }
+
+    public void setNumber(int number) {
+        this.number = number;
+    }
+
+    public int getOffsetEndInPage() {
+        return getLast(tokens).getOffset();
+    }
+
+    public boolean isIgnored() {
+        return ignored;
+    }
+
+    public void setIgnored(boolean ignored) {
+        this.ignored = ignored;
+    }
+}