Java tutorial
/** * Copyright (C) 2010-2016 Structr GmbH * * This file is part of Structr <http://structr.org>. * * Structr is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * Structr is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with Structr. If not, see <http://www.gnu.org/licenses/>. */ package org.structr.text; import java.util.LinkedHashSet; import java.util.Set; import org.apache.commons.lang3.StringUtils; import org.structr.common.error.FrameworkException; import org.structr.common.fulltext.FulltextIndexer; import org.structr.common.fulltext.Indexable; import org.structr.core.GraphObjectMap; import org.structr.core.app.StructrApp; import org.structr.core.entity.AbstractSchemaNode; import org.structr.core.property.GenericProperty; import org.structr.module.StructrModule; import org.structr.schema.action.Actions; /** * */ public class FulltextIndexerModule implements FulltextIndexer, StructrModule { @Override public void onLoad() { } @Override public void addToFulltextIndex(final Indexable node) throws FrameworkException { StructrApp.getInstance(node.getSecurityContext()).processTasks(new FulltextIndexingTask(node)); } @Override public GraphObjectMap getContextObject(final String searchTerm, final String text, final int contextLength) { final GraphObjectMap contextObject = new GraphObjectMap(); final Set<String> contextValues = new LinkedHashSet<>(); final String[] searchParts = searchTerm.split("[\\s,;]+"); final GenericProperty contextKey = new GenericProperty("context"); for (final String searchString : searchParts) { final String lowerCaseSearchString = searchString.toLowerCase(); final String lowerCaseText = text.toLowerCase(); final StringBuilder wordBuffer = new StringBuilder(); final StringBuilder lineBuffer = new StringBuilder(); final int textLength = text.length(); /* * we take an average word length of 8 characters, multiply * it by the desired prefix and suffix word count, add 20% * and try to extract up to prefixLength words. */ // modify these parameters to tune prefix and suffix word extraction // loop variables int newlineCount = 0; int wordCount = 0; // wordCount starts at 1 because we include the matching word int pos = -1; do { // find next occurrence pos = lowerCaseText.indexOf(lowerCaseSearchString, pos + 1); if (pos > 0) { lineBuffer.setLength(0); wordBuffer.setLength(0); wordCount = 0; newlineCount = 0; // fetch context words before search hit for (int i = pos; i >= 0; i--) { final char c = text.charAt(i); if (!Character.isAlphabetic(c) && !Character.isDigit(c) && !FulltextTokenizer.SpecialChars.contains(c)) { wordCount += flushWordBuffer(lineBuffer, wordBuffer, true); // store character in buffer wordBuffer.insert(0, c); if (c == '\n') { // increase newline count newlineCount++; } else { // reset newline count newlineCount = 0; } // paragraph boundary reached if (newlineCount > 1) { break; } // stop if we collected half of the desired word count if (wordCount > contextLength / 2) { break; } } else { // store character in buffer wordBuffer.insert(0, c); // reset newline count newlineCount = 0; } } wordCount += flushWordBuffer(lineBuffer, wordBuffer, true); wordBuffer.setLength(0); // fetch context words after search hit for (int i = pos + 1; i < textLength; i++) { final char c = text.charAt(i); if (!Character.isAlphabetic(c) && !Character.isDigit(c) && !FulltextTokenizer.SpecialChars.contains(c)) { wordCount += flushWordBuffer(lineBuffer, wordBuffer, false); // store character in buffer wordBuffer.append(c); if (c == '\n') { // increase newline count newlineCount++; } else { // reset newline count newlineCount = 0; } // paragraph boundary reached if (newlineCount > 1) { break; } // stop if we collected enough words if (wordCount > contextLength) { break; } } else { // store character in buffer wordBuffer.append(c); // reset newline count newlineCount = 0; } } wordCount += flushWordBuffer(lineBuffer, wordBuffer, false); // replace single newlines with space contextValues.add(lineBuffer.toString().trim()); } } while (pos >= 0); } contextObject.put(contextKey, contextValues); return contextObject; } // ----- interface StructrModule ----- @Override public String getName() { return "text-search"; } @Override public Set<String> getDependencies() { return null; } @Override public Set<String> getFeatures() { return null; } @Override public void insertImportStatements(final AbstractSchemaNode schemaNode, final StringBuilder buf) { } @Override public void insertSourceCode(final AbstractSchemaNode schemaNode, final StringBuilder buf) { } @Override public Set<String> getInterfacesForType(final AbstractSchemaNode schemaNode) { return null; } @Override public void insertSaveAction(final AbstractSchemaNode schemaNode, final StringBuilder buf, final Actions.Type type) { } //~--- private methods -------------------------------------------------------- private static int flushWordBuffer(final StringBuilder lineBuffer, final StringBuilder wordBuffer, final boolean prepend) { int wordCount = 0; if (wordBuffer.length() > 0) { final String word = wordBuffer.toString().replaceAll("[\\n\\t]+", " "); if (StringUtils.isNotBlank(word)) { if (prepend) { lineBuffer.insert(0, word); } else { lineBuffer.append(word); } // increase word count wordCount = 1; } wordBuffer.setLength(0); } return wordCount; } }