/**
* First pass to detect basic structures: remove page header/footer, identify section numbering,
* identify Figure and table blocks.
*
* <p>-> to be removed at some point!
*
* @param doc a document
*/
public static void firstPass(Document doc) {
if (doc == null) {
throw new NullPointerException();
}
if (doc.getBlocks() == null) {
throw new NullPointerException();
}
int i = 0;
List<Integer> blockHeaders = new ArrayList<Integer>();
List<Integer> blockFooters = new ArrayList<Integer>();
List<Integer> blockSectionTitles = new ArrayList<Integer>();
List<Integer> acknowledgementBlocks = new ArrayList<Integer>();
List<Integer> blockTables = new ArrayList<Integer>();
List<Integer> blockFigures = new ArrayList<Integer>();
List<Integer> blockHeadTables = new ArrayList<Integer>();
List<Integer> blockHeadFigures = new ArrayList<Integer>();
List<Integer> blockDocumentHeaders = new ArrayList<Integer>();
doc.setTitleMatchNum(false);
try {
for (Block block : doc.getBlocks()) {
String localText = block.getText().trim();
localText = localText.replace("\n", " ");
localText = localText.replace(" ", " ");
localText = localText.trim();
Matcher ma1 = BasicStructureBuilder.introduction.matcher(localText);
Matcher ma2 = BasicStructureBuilder.references.matcher(localText);
if ((ma1.find()) || (ma2.find())) {
if (((localText.startsWith("1.")) || (localText.startsWith("1 ")))
|| ((localText.startsWith("2.")) || (localText.startsWith("2 ")))
|| (localText.startsWith("Contents"))) doc.setTitleMatchNum(true);
// System.out.println("Title section identified: block " + i + ", " + localText);
blockSectionTitles.add(i);
} else {
StringTokenizer st = new StringTokenizer(localText, "\n");
while (st.hasMoreTokens()) {
String token = st.nextToken();
if (token.startsWith("@PAGE")) {
// current block should give the header/footors
if (i > 4) {
if (doc.getBlocks().get(i - 5).getNbTokens() < 20) {
Integer i2 = i - 5;
if (!blockFooters.contains(i2)) blockFooters.add(i2);
}
}
if (i > 3) {
if (doc.getBlocks().get(i - 4).getNbTokens() < 20) {
Integer i2 = i - 4;
if (!blockFooters.contains(i2)) blockFooters.add(i2);
}
}
if (i > 2) {
if (doc.getBlocks().get(i - 3).getNbTokens() < 20) {
Integer i2 = i - 3;
if (!blockFooters.contains(i2)) blockFooters.add(i2);
}
}
if (i > 1) {
if (doc.getBlocks().get(i - 2).getNbTokens() < 20) {
Integer i2 = i - 2;
if (!blockFooters.contains(i2)) blockFooters.add(i2);
}
}
if (i > 0) {
if (doc.getBlocks().get(i - 1).getNbTokens() < 20) {
Integer i2 = i - 1;
if (!blockFooters.contains(i2)) blockFooters.add(i2);
}
}
blockFooters.add(i);
// page header candidates
blockHeaders.add(i);
if (i < doc.getBlocks().size() - 1) {
if (doc.getBlocks().get(i + 1).getNbTokens() < 20) {
Integer i2 = i + 1;
if (!blockHeaders.contains(i2)) blockHeaders.add(i + 1);
}
}
if (i < doc.getBlocks().size() - 2) {
if (doc.getBlocks().get(i + 2).getNbTokens() < 20) {
Integer i2 = i + 2;
if (!blockHeaders.contains(i2)) blockHeaders.add(i + 2);
}
}
if (i < doc.getBlocks().size() - 3) {
if (doc.getBlocks().get(i + 3).getNbTokens() < 20) {
Integer i2 = i + 3;
if (!blockHeaders.contains(i2)) blockHeaders.add(i + 3);
}
}
if (i < doc.getBlocks().size() - 4) {
if (doc.getBlocks().get(i + 4).getNbTokens() < 20) {
Integer i2 = i + 4;
if (!blockHeaders.contains(i2)) blockHeaders.add(i + 4);
}
}
// more ??
}
}
}
// clustering of blocks per font (for section header and figure/table detections)
addBlockToCluster(i, doc);
i++;
}
// try to find the cluster of section titles
Cluster candidateCluster = null;
// System.out.println("nb clusters: " + clusters.size());
for (Cluster cluster : doc.getClusters()) {
if ((cluster.getNbBlocks() < (doc.getBlocks().size() / 5))
&& (cluster.getNbBlocks() < 20)) {
List<Integer> blo = cluster.getBlocks2();
for (Integer b : blo) {
if (blockSectionTitles.contains(b)) {
if (candidateCluster == null) {
candidateCluster = cluster;
break;
}
// else if (cluster.getFontSize() >= candidateCluster.getFontSize())
// candidateCluster = cluster;
}
}
}
}
if (candidateCluster != null) {
List<Integer> newBlockSectionTitles = new ArrayList<Integer>();
for (Integer bl : blockSectionTitles) {
if (!newBlockSectionTitles.contains(bl)) newBlockSectionTitles.add(bl);
}
List<Integer> blockClusterTitles = candidateCluster.getBlocks2();
if (blockClusterTitles.size() < 20) {
for (Integer bl : blockClusterTitles) {
if (!newBlockSectionTitles.contains(bl)) newBlockSectionTitles.add(bl);
}
}
blockSectionTitles = newBlockSectionTitles;
}
// aknowledgement section recognition
boolean ackn = false;
i = 0;
for (Block block : doc.getBlocks()) {
String localText = block.getText().trim();
localText = localText.replace("\n", " ");
localText = localText.replace(" ", " ");
localText = localText.trim();
// System.out.println(i + ": " + localText+"\n");
Integer iii = i;
Matcher m3 = BasicStructureBuilder.acknowledgement.matcher(localText);
if ((m3.find()) && (blockSectionTitles.contains(iii))) {
acknowledgementBlocks.add(iii);
ackn = true;
// int index = blockSectionTitles.indexOf(iii);
// blockSectionTitles.remove(index);
} else if ((ackn) && (blockSectionTitles.contains(iii))) {
ackn = false;
break;
} else if (ackn) {
Matcher m4 = BasicStructureBuilder.references.matcher(localText);
if ((ackn) && (!blockFooters.contains(iii)) && (!m4.find())) {
acknowledgementBlocks.add(iii);
} else if (m4.find()) {
ackn = false;
break;
}
}
i++;
}
// we remove references headers in blockSectionTitles
int index = -1;
for (Integer ii : blockSectionTitles) {
Block block = doc.getBlocks().get(ii);
String localText = block.getText().trim();
localText = localText.replace("\n", " ");
localText = localText.replace(" ", " ");
localText = localText.trim();
Matcher m4 = BasicStructureBuilder.references.matcher(localText);
if (m4.find()) {
index = blockSectionTitles.indexOf(ii);
break;
}
}
if (index != -1) {
blockSectionTitles.remove(index);
}
// we check headers repetition from page to page to decide if it is an header or not
ArrayList<Integer> toRemove = new ArrayList<Integer>();
for (Integer ii : blockHeaders) {
String localText = (doc.getBlocks().get(ii)).getText().trim();
localText = TextUtilities.shadowNumbers(localText);
int length = localText.length();
if (length > 160) toRemove.add(ii);
else {
// System.out.println("header candidate: " + localText);
// evaluate distance with other potential headers
boolean valid = false;
for (Integer ii2 : blockHeaders) {
if (ii.intValue() != ii2.intValue()) {
String localText2 = doc.getBlocks().get(ii2).getText().trim();
if (localText2.length() < 160) {
localText2 = TextUtilities.shadowNumbers(localText2);
double dist =
(double) TextUtilities.getLevenshteinDistance(localText, localText2) / length;
// System.out.println("dist with " + localText2 + " : " + dist);
if (dist < 0.25) {
valid = true;
break;
}
}
}
}
if (!valid) {
toRemove.add(ii);
}
}
}
for (Integer ii : toRemove) {
blockHeaders.remove(ii);
}
// same for footers
toRemove = new ArrayList<Integer>();
for (Integer ii : blockFooters) {
String localText = (doc.getBlocks().get(ii)).getText().trim();
localText = TextUtilities.shadowNumbers(localText);
int length = localText.length();
if (length > 160) toRemove.add(ii);
else {
// System.out.println("footer candidate: " + localText);
// evaluate distance with other potential headers
boolean valid = false;
for (Integer ii2 : blockFooters) {
if (ii.intValue() != ii2.intValue()) {
String localText2 = doc.getBlocks().get(ii2).getText().trim();
if (localText2.length() < 160) {
localText2 = TextUtilities.shadowNumbers(localText2);
double dist =
(double) TextUtilities.getLevenshteinDistance(localText, localText2) / length;
if (dist < 0.25) {
valid = true;
break;
}
}
}
}
if (!valid) {
toRemove.add(ii);
}
}
}
for (Integer ii : toRemove) {
blockFooters.remove(ii);
}
// a special step for added banner repositoryies such HAL
i = 0;
for (Block block : doc.getBlocks()) {
String localText = block.getText().trim();
localText = localText.replace("\n", " ");
localText = localText.replace(" ", " ");
localText = localText.trim();
// HAL
if (localText.startsWith("Author manuscript, published in")) {
Double y = block.getY();
// System.out.println("HAL banner found, " + "block " + i + ", y = " + y);
if (Math.abs(y - 12.538) < 2) { // reference position
// blockHeaders.add(new Integer(i));
blockDocumentHeaders.add(i);
// System.out.println("HAL banner added as header block");
break;
}
}
// ACM publications
// System.out.println("test ACM " + i);
// System.out.println(localText);
if (localText.startsWith("Permission to make digital or hard copies")) {
blockFooters.add(i);
break;
}
// arXiv, etc. put here
// IOP
if (localText.startsWith("Confidential: ") && (localText.contains("IOP"))) {
blockDocumentHeaders.add(i);
// System.out.println("IOP banner added as header block");
break;
}
i++;
}
// we try to recognize here table and figure blocks
// the idea is that the textual elements are not located as the normal text blocks
// this is recognized by exploiting the cluster of blocks starting up and down front the block
// containing a table or a figure marker
// two different runs, one for figures and one for tables (everything could be done in one
// step)
i = 0;
for (Block block : doc.getBlocks()) {
String localText = block.getText().trim();
localText = localText.replace("\n", " ");
localText = localText.replace(" ", " ");
localText = localText.trim();
Matcher m = BasicStructureBuilder.figure.matcher(localText);
Matcher m2 = BasicStructureBuilder.table.matcher(localText);
double width = block.getWidth();
boolean bold = block.getBold();
// table
// if ( (m2.find()) && (localText.length() < 200) ) {
if ((m2.find()) && ((bold) || (localText.length() < 200))) {
if (!blockHeadTables.contains(i)) {
blockHeadTables.add(i);
}
// we also put all the small blocks before and after the marker
int j = i - 1;
while ((j > i - 15) && (j > 0)) {
Block b = doc.getBlocks().get(j);
if (b.getText() != null) {
if ((b.getText().length() < 160) || (width < 50)) {
if ((!blockTables.contains(j))
&& (!blockSectionTitles.contains(j))
&& (!blockHeaders.contains(j))
&& (!blockFooters.contains(j))) blockTables.add(j);
} else j = 0;
}
j--;
}
j = i + 1;
while ((j < i + 15) && (j < doc.getBlocks().size())) {
Block b = doc.getBlocks().get(j);
if (b.getText() != null) {
if ((b.getText().length() < 160) || (width < 50)) {
if ((!blockTables.contains(j))
&& (!blockSectionTitles.contains(j))
&& (!blockHeaders.contains(j))
&& (!blockFooters.contains(j))) blockTables.add(j);
} else j = doc.getBlocks().size();
}
j++;
}
}
// figure
// else if ( (m.find()) && (localText.length() < 200) ) {
else if ((m.find()) && ((bold) || (localText.length() < 200))) {
if (!blockHeadFigures.contains(i)) blockHeadFigures.add(i);
// we also put all the small blocks before and after the marker
int j = i - 1;
boolean imageFound = false;
while ((j > i - 15) && (j > 0)) {
Block b = doc.getBlocks().get(j);
if (b.getText() != null) {
String localText2 = b.getText().trim();
// localText = localText.replace("\n", " ");
localText2 = localText2.replace(" ", " ");
localText2 = localText2.trim();
if ((localText2.startsWith("@IMAGE")) && (!imageFound)) {
// System.out.println(localText2);
block.setText(block.getText() + " " + localText2);
// System.out.println(block.getText());
imageFound = true;
}
if ((localText2.length() < 160) || (width < 50)) {
if ((!blockFigures.contains(j))
&& (!blockSectionTitles.contains(j))
&& (!blockHeaders.contains(j))
&& (!blockFooters.contains(j))) blockFigures.add(j);
} else j = 0;
}
j--;
}
j = i + 1;
while ((j < i + 15) && (j < doc.getBlocks().size())) {
Block b = doc.getBlocks().get(j);
if (b.getText() != null) {
if ((b.getText().trim().length() < 160) || (width < 50)) {
if ((!blockFigures.contains(j))
&& (!blockSectionTitles.contains(j))
&& (!blockHeaders.contains(j))
&& (!blockFooters.contains(j))) blockFigures.add(j);
} else j = doc.getBlocks().size();
}
j++;
}
}
i++;
}
} finally {
doc.setBlockHeaders(blockHeaders);
doc.setBlockFooters(blockFooters);
doc.setBlockSectionTitles(blockSectionTitles);
doc.setAcknowledgementBlocks(acknowledgementBlocks);
doc.setBlockTables(blockTables);
doc.setBlockFigures(blockFigures);
doc.setBlockHeadTables(blockHeadTables);
doc.setBlockHeadFigures(blockHeadFigures);
doc.setBlockDocumentHeaders(blockDocumentHeaders);
}
}
