/**
* Copyright (C) 2013 Christian Kohlschütter (ckkohl79@gmail.com)
*
* Licensed 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 de.l3s.boilerpipe.filters.heuristics;
import java.util.List;
import java.util.ListIterator;
import java.util.Set;
import de.l3s.boilerpipe.BoilerpipeFilter;
import de.l3s.boilerpipe.BoilerpipeProcessingException;
import de.l3s.boilerpipe.document.TextBlock;
import de.l3s.boilerpipe.document.TextDocument;
/**
* Adds the labels of the preceding block to the current block, optionally adding a prefix.
*
* @author Christian Kohlschütter
*/
public final class AddPrecedingLabelsFilter implements BoilerpipeFilter {
public static final AddPrecedingLabelsFilter INSTANCE = new AddPrecedingLabelsFilter("");
public static final AddPrecedingLabelsFilter INSTANCE_PRE = new AddPrecedingLabelsFilter("^");
private final String labelPrefix;
/**
* Creates a new {@link de.l3s.boilerpipe.filters.heuristics.AddPrecedingLabelsFilter} instance.
*
*/
public AddPrecedingLabelsFilter(final String labelPrefix) {
this.labelPrefix = labelPrefix;
}
public boolean process(TextDocument doc)
throws BoilerpipeProcessingException {
List<TextBlock> textBlocks = doc.getTextBlocks();
if (textBlocks.size() < 2) {
return false;
}
boolean changes = false;
int remaining = textBlocks.size();
TextBlock blockBelow = null;
TextBlock block;
for (ListIterator<TextBlock> it = textBlocks.listIterator(textBlocks.size()); it
.hasPrevious();) {
if(--remaining <= 0) {
break;
}
if(blockBelow == null) {
blockBelow = it.previous();
continue;
}
block = it.previous();
Set<String> labels = block.getLabels();
if(labels != null && !labels.isEmpty()) {
for(String l : labels) {
blockBelow.addLabel(labelPrefix+l);
}
changes = true;
}
blockBelow = block;
}
return changes;
}
}