package org.opencms.util;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.htmlparser.Tag;
import org.htmlparser.Text;
import org.htmlparser.util.Translate;
/**
* Extracts the HTML page content.<p>
*/
public class CmsHtml2TextConverter extends CmsHtmlParser {
/** Indicated to append or store the next line breaks. */
private boolean m_appendBr;
/** Map of stored attributes that must be written to the output when the tag closes. */
private Map<Tag, String> m_attributeMap;
/** The last appended line break count. */
private int m_brCount;
/** The current indentation. */
private int m_indent;
/** The current line length. */
private int m_lineLength;
/** The marker String (for headlines, bullets etc.). */
private String m_marker;
/** The maximum line length. */
private int m_maxLineLength;
/** The last stored, but not appended line break count. */
private int m_storedBrCount;
/**
* Creates a new instance of the html converter.<p>
*/
public CmsHtml2TextConverter() {
m_result = new StringBuffer(512);
m_maxLineLength = 100;
m_attributeMap = new HashMap<Tag, String>(16);
}
/**
* Extracts the text from the given html content, assuming the given html encoding.<p>
*
* @param html the content to extract the plain text from
* @param encoding the encoding to use
*
* @return the text extracted from the given html content
*
* @throws Exception if something goes wrong
*/
public static String html2text(String html, String encoding) throws Exception {
// create the converter instance
CmsHtml2TextConverter visitor = new CmsHtml2TextConverter();
return visitor.process(html, encoding);
}
/**
* @see org.htmlparser.visitors.NodeVisitor#visitEndTag(org.htmlparser.Tag)
*/
@Override
public void visitEndTag(Tag tag) {
m_appendBr = false;
appendLinebreaks(tag, false);
String attribute = m_attributeMap.remove(tag.getParent());
if (attribute != null) {
appendText(attribute);
}
}
/**
* @see org.htmlparser.visitors.NodeVisitor#visitStringNode(org.htmlparser.Text)
*/
@Override
public void visitStringNode(Text text) {
appendText(text.toPlainTextString());
}
/**
* @see org.htmlparser.visitors.NodeVisitor#visitTag(org.htmlparser.Tag)
*/
@Override
public void visitTag(Tag tag) {
m_appendBr = true;
appendLinebreaks(tag, true);
if (tag.getTagName().equals("IMG")) {
appendText("##IMG##");
}
String href = tag.getAttribute("href");
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(href)) {
appendAttribute(tag, " [" + href.trim() + "]");
}
String src = tag.getAttribute("src");
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(src)) {
appendAttribute(tag, " [" + src.trim() + "]");
}
String title = tag.getAttribute("title");
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(title)) {
appendAttribute(tag, " {" + title.trim() + "}");
}
String alt = tag.getAttribute("alt");
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(alt)) {
appendAttribute(tag, " {" + alt.trim() + "}");
}
}
private void appendAttribute(Tag tag, String text) {
if (tag.getTagName().equals("IMG")) {
appendText(text);
} else {
String current = m_attributeMap.get(tag);
if (current != null) {
text = current + text;
}
m_attributeMap.put(tag, text);
}
}
private void appendIndentation() {
if (m_lineLength <= m_indent) {
int len = (m_marker != null) ? m_indent - (m_marker.length() + 1) : m_indent;
for (int i = 0; i < len; i++) {
m_result.append(' ');
}
if (m_marker != null) {
m_result.append(m_marker);
m_result.append(' ');
m_marker = null;
}
}
}
private void appendLinebreak(int count) {
appendLinebreak(count, false);
}
private void appendLinebreak(int count, boolean force) {
if (m_appendBr) {
if (m_storedBrCount > count) {
count = m_storedBrCount;
}
m_storedBrCount = 0;
if (force) {
m_brCount = 0;
}
while (m_brCount < count) {
m_result.append("\r\n");
m_brCount++;
}
m_lineLength = m_indent;
} else {
while (m_storedBrCount < count) {
m_storedBrCount++;
}
}
}
private void appendLinebreaks(Tag tag, boolean open) {
String name = tag.getTagName();
int pos = TAG_LIST.indexOf(name);
switch (pos) {
case 0: // H1
setMarker("=", open);
setIndentation(2, open);
appendLinebreak(2);
break;
case 1: // H2
setMarker("==", open);
setIndentation(3, open);
appendLinebreak(2);
break;
case 2: // H3
setMarker("===", open);
setIndentation(4, open);
appendLinebreak(2);
break;
case 3: // H4
setMarker("====", open);
setIndentation(5, open);
appendLinebreak(2);
break;
case 4: // H5
setMarker("=====", open);
setIndentation(6, open);
appendLinebreak(2);
break;
case 5: // H6
setMarker("=======", open);
setIndentation(7, open);
appendLinebreak(2);
break;
case 6: // P
case 7: // DIV
appendLinebreak(2);
break;
case 8: // SPAN
break;
case 9: // BR
appendLinebreak(1, true);
break;
case 10: // OL
case 11: // UL
appendLinebreak(2);
break;
case 12: // LI
setMarker("*", open);
setIndentation(5, open);
appendLinebreak(1);
break;
case 13: // TABLE
setIndentation(5, open);
appendLinebreak(2);
if (open) {
appendLinebreak(1);
appendText("-----");
appendLinebreak(1);
}
break;
case 14: // TD
setMarker("--", open);
appendLinebreak(2);
break;
case 15: // TR
if (!open) {
appendLinebreak(1);
appendText("-----");
appendLinebreak(1);
}
break;
case 16: // TH
case 17: // THEAD
case 18: // TBODY
case 19: // TFOOT
appendLinebreak(1);
break;
default: // unknown tag (ignore)
}
}
private void appendText(String text) {
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(text)) {
text = Translate.decode(text);
text = collapse(text);
}
if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(text)) {
if (m_storedBrCount > 0) {
m_appendBr = true;
appendLinebreak(m_storedBrCount);
}
appendIndentation();
m_brCount = 0;
List<String> wordList = CmsStringUtil.splitAsList(text, ' ');
Iterator<String> i = wordList.iterator();
while (i.hasNext()) {
String word = i.next();
boolean hasNbsp = ((word.charAt(0) == 160) || (word.charAt(word.length() - 1) == 160));
if ((word.length() + 1 + m_lineLength) > m_maxLineLength) {
m_appendBr = true;
appendLinebreak(1);
appendIndentation();
m_brCount = 0;
} else {
if (!hasNbsp
&& (m_lineLength > m_indent)
&& (m_result.charAt(m_result.length() - 1) != 160)
&& (m_result.charAt(m_result.length() - 1) != 32)) {
m_result.append(' ');
m_lineLength++;
}
}
m_result.append(word);
m_lineLength += word.length();
}
}
}
private void setIndentation(int length, boolean open) {
if (open) {
m_indent += length;
} else {
m_indent -= length;
if (m_indent < 0) {
m_indent = 0;
}
}
}
private void setMarker(String marker, boolean open) {
if (open) {
m_marker = marker;
}
}
}