ViterbiFormatter.java

/**
 * Copyright © 2010-2012 Atilika Inc.  All rights reserved.
 *
 * Atilika Inc. 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.  A copy of the License is distributed with this work in the
 * LICENSE.txt file.  You may also obtain a copy of the License from
 *
 *   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 org.atilika.kuromoji.viterbi;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.atilika.kuromoji.dict.ConnectionCosts;
import org.atilika.kuromoji.viterbi.ViterbiNode.Type;

/**
 * クラス名が変わった
 *
 * @author Masaru Hasegawa
 * @author Christian Moen
 */
public class ViterbiFormatter {

	private final static String BOS_LABEL = "BOS";

	private final static String EOS_LABEL = "EOS";

	private final static String FONT_NAME = "Helvetica";

	private ConnectionCosts costs;

	private Map<String, ViterbiNode> nodeMap;

	private Map<String, String> bestPathMap;

	private boolean foundBOS;

	public ViterbiFormatter(ConnectionCosts costs) {
		this.costs = costs;
		this.nodeMap = new HashMap<String, ViterbiNode>();
		this.bestPathMap = new HashMap<String, String>();
	}

	public String format(ViterbiNode[][] startsArray, ViterbiNode[][] endsArray) {
		initBestPathMap(null);

		StringBuilder sb = new StringBuilder();
		sb.append(formatHeader());
		sb.append(formatNodes(startsArray, endsArray));
		sb.append(formatTrailer());
		return sb.toString();
	}

	public String format(ViterbiNode[][] startsArray, ViterbiNode[][] endsArray, List<ViterbiNode> bestPath) {

//		List<ViterbiNode> bestPathWithBOSAndEOS = new ArrayList<ViterbiNode>(bastPath);
		initBestPathMap(bestPath);

		StringBuilder sb = new StringBuilder();
		sb.append(formatHeader());
		sb.append(formatNodes(startsArray, endsArray));
		sb.append(formatTrailer());
		return sb.toString();

	}

	private void initBestPathMap(List<ViterbiNode> bestPath) {
		this.bestPathMap.clear();

		if (bestPath == null){
			return;
		}
		for (int i = 0; i < bestPath.size() - 1; i++) {
			ViterbiNode from = bestPath.get(i);
			ViterbiNode to = bestPath.get(i + 1);

			String fromId = getNodeId(from);
			String toId = getNodeId(to);

			assert this.bestPathMap.containsKey(fromId) == false;
			assert this.bestPathMap.containsValue(toId) == false;
			this.bestPathMap.put(fromId, toId);
		}
	}

	private String formatNodes(ViterbiNode[][] startsArray, ViterbiNode[][] endsArray) {
		this.nodeMap.clear();
		this.foundBOS = false;

		StringBuilder sb = new StringBuilder();
		for (int i = 1; i < endsArray.length; i++) {
			if(endsArray[i] == null || startsArray[i] == null) {
				continue;
			}
			for (int j = 0; j < endsArray[i].length; j++) {
				ViterbiNode from = endsArray[i][j];
				if(from == null){
					continue;
				}
				sb.append(formatNodeIfNew(from));
				for (int k = 0; k < startsArray[i].length; k++) {
					ViterbiNode to = startsArray[i][k];
					if(to == null){
						break;
					}
					sb.append(formatNodeIfNew(to));
					sb.append(formatEdge(from, to));
				}
			}
		}
		return sb.toString();
	}

	private String formatNodeIfNew(ViterbiNode node) {
		String nodeId = getNodeId(node);
		if (! this.nodeMap.containsKey(nodeId)) {
			this.nodeMap.put(nodeId, node);
			return formatNode(node);
		} else {
			return "";
		}
	}

	private String formatHeader() {
		StringBuilder sb = new StringBuilder();
		sb.append("digraph viterbi {\n");
		sb.append("graph [ fontsize=30 labelloc=\"t\" label=\"\" splines=true overlap=false rankdir = \"LR\" ];\n");
		sb.append("# A2 paper size\n");
		sb.append("size = \"34.4,16.5\";\n");
		sb.append("# try to fill paper\n");
		sb.append("ratio = fill;\n");
		sb.append("edge [ fontname=\"" + FONT_NAME + "\" fontcolor=\"red\" color=\"#606060\" ]\n");
		sb.append("node [ style=\"filled\" fillcolor=\"#e8e8f0\" shape=\"Mrecord\" fontname=\"" + FONT_NAME + "\" ]\n");

		return sb.toString();
	}

	private String formatTrailer() {
		return "}";
	}


	private String formatEdge(ViterbiNode from, ViterbiNode to) {
		if (this.bestPathMap.containsKey(getNodeId(from)) &&
			this.bestPathMap.get(getNodeId(from)).equals(getNodeId(to))) {
			return formatEdge(from, to, "color=\"#40e050\" fontcolor=\"#40a050\" penwidth=3 fontsize=20 ");

		} else {
			return formatEdge(from, to, "");
		}
	}


	private String formatEdge(ViterbiNode from, ViterbiNode to, String attributes) {
		StringBuilder sb = new StringBuilder();
		sb.append(getNodeId(from));
		sb.append(" -> ");
		sb.append(getNodeId(to));
		sb.append(" [ ");
		sb.append("label=\"");
		sb.append(getCost(from, to));
		sb.append("\"");
		sb.append(" ");
		sb.append(attributes);
		sb.append(" ");
		sb.append(" ]");
		sb.append("\n");
		return sb.toString();
	}

	private String formatNode(ViterbiNode node) {
		StringBuilder sb = new StringBuilder();
		sb.append("\"");
		sb.append(getNodeId(node));
		sb.append("\"");
		sb.append(" [ ");
		sb.append("label=");
		sb.append(formatNodeLabel(node));
		sb.append(" ]");
		return sb.toString();
	}

	private String formatNodeLabel(ViterbiNode node) {
		StringBuilder sb = new StringBuilder();
		sb.append("<<table border=\"0\" cellborder=\"0\">");
		sb.append("<tr><td>");
		sb.append(getNodeLabel(node));
		sb.append("</td></tr>");
		sb.append("<tr><td>");
		sb.append("<font color=\"blue\">");
		sb.append(node.getWordCost());
		sb.append("</font>");
		sb.append("</td></tr>");
//		sb.append("<tr><td>");
//		sb.append(this.dictionary.get(node.getWordId()).getPosInfo());
//		sb.append("</td></tr>");
		sb.append("</table>>");
		return sb.toString();
	}

	private String getNodeId(ViterbiNode node) {
		return String.valueOf(node.hashCode());
	}

	private String getNodeLabel(ViterbiNode node) {
		if (node.getType() == Type.KNOWN && node.getWordId() == 0) {
			if (this.foundBOS) {
				return EOS_LABEL;
			} else {
				this.foundBOS = true;
				return BOS_LABEL;
			}
		} else {
			return node.getSurfaceForm();
		}
	}

	private int getCost(ViterbiNode from, ViterbiNode to) {
		return this.costs.get(from.getLeftId(), to.getRightId());
	}
}