org.odftoolkit.simple.common.TextExtractor Maven / Gradle / Ivy
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to you under the Apache License, Version 2.0 (the
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specific language governing permissions and limitations
under the License.
*/
package org.odftoolkit.simple.common;
import org.odftoolkit.odfdom.dom.DefaultElementVisitor;
import org.odftoolkit.odfdom.dom.OdfDocumentNamespace;
import org.odftoolkit.odfdom.dom.element.text.TextHElement;
import org.odftoolkit.odfdom.dom.element.text.TextLineBreakElement;
import org.odftoolkit.odfdom.dom.element.text.TextPElement;
import org.odftoolkit.odfdom.dom.element.text.TextSElement;
import org.odftoolkit.odfdom.dom.element.text.TextTabElement;
import org.odftoolkit.odfdom.pkg.OdfElement;
import org.odftoolkit.odfdom.pkg.OdfNamespace;
import org.w3c.dom.Node;
/**
* This is a sub class of DefaultElementVisitor, which is used to
* extract display text from ODF element. For example, if you want to get all of
* the text content in a slide notes, you can call getOdfElement()
* to get the ODF element of this notes, then pass it to
* newOdfTextExtractor to create a TextExtractor. The last step is
* very easy, you only need to use getText(), all of the text
* content will be return as string. Another easier way is pass the ODF element
* to the static method TextExtractor.getText(OdfElement) directly.
*
* If you pass the content root which you can get by
* {@link org.odftoolkit.simple.Document#getContentRoot()
* Document.getContentRoot()} as the parameter, the whole document content will
* be returned, without any tag information.
*
* This extractor implements parts of ODF elements' white space handling
* functions. They are text:p, text:h, text:s, text:tab and text:linebreak,
* which visit() are override to process white space, according to
* ODF specification.
*
* @see org.odftoolkit.odfdom.pkg.OdfElement
*/
public class TextExtractor extends DefaultElementVisitor {
protected static final char NewLineChar = '\n';
protected static final char TabChar = '\t';
protected final ExtractorStringBuilder mTextBuilder;
OdfElement mElement;
/**
* This class is used to provide the string builder functions to extractor.
* It will automatically process the last NewLineChar.
*
* @since 0.3.5
*/
protected static class ExtractorStringBuilder {
private StringBuilder mBuilder;
private boolean lastAppendNewLine;
ExtractorStringBuilder() {
mBuilder = new StringBuilder();
lastAppendNewLine = false;
}
/**
* Append a string
*
* @param str
* - the string
*/
public void append(String str) {
mBuilder.append(str);
}
/**
* Append a character
*
* @param ch
* - the character
*/
public void append(char ch) {
mBuilder.append(ch);
}
/**
* Append a new line character at the end
*/
public void appendLine() {
mBuilder.append(NewLineChar);
lastAppendNewLine = true;
}
/**
* Return the string value.
*
* If the last character is a new line character and is appended with
* appendLine(), the last new line character will be removed.
*/
public String toString() {
if (lastAppendNewLine) {
mBuilder.deleteCharAt(mBuilder.length() - 1);
}
return mBuilder.toString();
}
}
/**
* Return the text content of a element as String
*
* @param ele
* the ODF element
* @return the text content of the element
*/
public static synchronized String getText(OdfElement ele) {
TextExtractor extractor = newOdfTextExtractor(ele);
return extractor.getText();
}
/**
* Create a TextExtractor instance using specified ODF element, which text
* content can be extracted by getText().
*
* @param element
* the ODF element whose text will be extracted.
* @return an instance of TextExtractor
*/
public static TextExtractor newOdfTextExtractor(OdfElement element) {
return new TextExtractor(element);
}
/**
* Return the text content of specified ODF element as a string.
*
* @return the text content as a string
*/
public String getText() {
visit(mElement);
return mTextBuilder.toString();
}
/**
* Default constructor
*/
protected TextExtractor() {
mTextBuilder = new ExtractorStringBuilder();
}
/**
* Constructor with an ODF element as parameter
*
* @param element
* the ODF element whose text would be extracted.
*/
protected TextExtractor(OdfElement element) {
mTextBuilder = new ExtractorStringBuilder();
mElement = element;
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of OdfElement.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.pkg.OdfElement)
*/
@Override
public void visit(OdfElement element) {
appendElementText(element);
if (OdfDocumentNamespace.META.getUri().equals(element.getNamespaceURI())
|| OdfDocumentNamespace.DC.getUri().equals(element.getNamespaceURI())) {
mTextBuilder.appendLine();
}
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of text:p.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.dom.element.text.TextPElement)
*/
@Override
public void visit(TextPElement ele) {
appendElementText(ele);
mTextBuilder.appendLine();
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of text:h.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.dom.element.text.TextHElement)
*/
@Override
public void visit(TextHElement ele) {
appendElementText(ele);
mTextBuilder.appendLine();
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of text:s.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.dom.element.text.TextSElement)
*/
@Override
public void visit(TextSElement ele) {
Integer count = ele.getTextCAttribute();
if (count == null) {
count = 1;
}
for (int i = 0; i < count; i++) {
mTextBuilder.append(' ');
}
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of text:tab.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.dom.element.text.TextTabElement)
*/
@Override
public void visit(TextTabElement ele) {
mTextBuilder.append(TabChar);
}
/**
* The end users needn't to care of this method, if you don't want to
* override the text content handling strategy of text:linebreak.
*
* @see org.odftoolkit.odfdom.dom.DefaultElementVisitor#visit(org.odftoolkit.odfdom.dom.element.text.TextLineBreakElement)
*/
@Override
public void visit(TextLineBreakElement ele) {
mTextBuilder.append(NewLineChar);
}
/**
* Append the text content of this element to string buffer.
*
* @param ele
* the ODF element whose text will be appended.
*/
protected void appendElementText(OdfElement ele) {
Node node = ele.getFirstChild();
while (node != null) {
if (node.getNodeType() == Node.TEXT_NODE) {
mTextBuilder.append(node.getNodeValue());
} else if (node.getNodeType() == Node.ELEMENT_NODE) {
OdfElement element = (OdfElement) node;
element.accept(this);
}
node = node.getNextSibling();
}
}
}