javanet.staxutils.IndentingXMLStreamWriter Maven / Gradle / Ivy
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/*
* Copyright (c) 2006, John Kristian
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of StAX-Utils nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
package javanet.staxutils;
import javanet.staxutils.helpers.StreamWriterDelegate;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
/**
* A filter that indents an XML stream. To apply it, construct a filter that
* contains another {@link XMLStreamWriter}, which you pass to the constructor.
* Then call methods of the filter instead of the contained stream. For example:
*
*
* {@link XMLStreamWriter} stream = ...
* stream = new {@link IndentingXMLStreamWriter}(stream);
* stream.writeStartDocument();
* ...
*
*
*
* The filter inserts characters to format the document as an outline, with
* nested elements indented. Basically, it inserts a line break and whitespace
* before:
*
* - each DTD, processing instruction or comment that's not preceded by data
* - each starting tag that's not preceded by data
* - each ending tag that's preceded by nested elements but not data
*
* This works well with 'data-oriented' XML, wherein each element contains
* either data or nested elements but not both. It can work badly with other
* styles of XML. For example, the data in a 'mixed content' document are apt to
* be polluted with indentation characters.
*
* Indentation can be adjusted by setting the newLine and indent properties. But
* set them to whitespace only, for best results. Non-whitespace is apt to cause
* problems, for example when this class attempts to insert newLine before the
* root element.
*
* @author John Kristian
*/
public class IndentingXMLStreamWriter extends StreamWriterDelegate implements Indentation {
public IndentingXMLStreamWriter(XMLStreamWriter out) {
super(out);
}
/** How deeply nested the current scope is. The root element is depth 1. */
private int depth = 0; // document scope
/** stack[depth] indicates what's been written into the current scope. */
private int[] stack = new int[] { 0, 0, 0, 0 }; // nothing written yet
private static final int WROTE_MARKUP = 1;
private static final int WROTE_DATA = 2;
private String indent = DEFAULT_INDENT;
private String newLine = NORMAL_END_OF_LINE;
/** newLine followed by copies of indent. */
private char[] linePrefix = null;
public void setIndent(String indent) {
if (!indent.equals(this.indent)) {
this.indent = indent;
linePrefix = null;
}
}
public String getIndent() {
return indent;
}
public void setNewLine(String newLine) {
if (!newLine.equals(this.newLine)) {
this.newLine = newLine;
linePrefix = null;
}
}
/**
* @return System.getProperty("line.separator"); or
* {@link #NORMAL_END_OF_LINE} if that fails.
*/
public static String getLineSeparator() {
try {
return System.getProperty("line.separator");
} catch (SecurityException ignored) {
}
return NORMAL_END_OF_LINE;
}
public String getNewLine() {
return newLine;
}
public void writeStartDocument() throws XMLStreamException {
beforeMarkup();
out.writeStartDocument();
afterMarkup();
}
public void writeStartDocument(String version) throws XMLStreamException {
beforeMarkup();
out.writeStartDocument(version);
afterMarkup();
}
public void writeStartDocument(String encoding, String version) throws XMLStreamException {
beforeMarkup();
out.writeStartDocument(encoding, version);
afterMarkup();
}
public void writeDTD(String dtd) throws XMLStreamException {
beforeMarkup();
out.writeDTD(dtd);
afterMarkup();
}
public void writeProcessingInstruction(String target) throws XMLStreamException {
beforeMarkup();
out.writeProcessingInstruction(target);
afterMarkup();
}
public void writeProcessingInstruction(String target, String data) throws XMLStreamException {
beforeMarkup();
out.writeProcessingInstruction(target, data);
afterMarkup();
}
public void writeComment(String data) throws XMLStreamException {
beforeMarkup();
out.writeComment(data);
afterMarkup();
}
public void writeEmptyElement(String localName) throws XMLStreamException {
beforeMarkup();
out.writeEmptyElement(localName);
afterMarkup();
}
public void writeEmptyElement(String namespaceURI, String localName) throws XMLStreamException {
beforeMarkup();
out.writeEmptyElement(namespaceURI, localName);
afterMarkup();
}
public void writeEmptyElement(String prefix, String localName, String namespaceURI)
throws XMLStreamException {
beforeMarkup();
out.writeEmptyElement(prefix, localName, namespaceURI);
afterMarkup();
}
public void writeStartElement(String localName) throws XMLStreamException {
beforeStartElement();
out.writeStartElement(localName);
afterStartElement();
}
public void writeStartElement(String namespaceURI, String localName) throws XMLStreamException {
beforeStartElement();
out.writeStartElement(namespaceURI, localName);
afterStartElement();
}
public void writeStartElement(String prefix, String localName, String namespaceURI)
throws XMLStreamException {
beforeStartElement();
out.writeStartElement(prefix, localName, namespaceURI);
afterStartElement();
}
public void writeCharacters(String text) throws XMLStreamException {
out.writeCharacters(text);
afterData();
}
public void writeCharacters(char[] text, int start, int len) throws XMLStreamException {
out.writeCharacters(text, start, len);
afterData();
}
public void writeCData(String data) throws XMLStreamException {
out.writeCData(data);
afterData();
}
public void writeEntityRef(String name) throws XMLStreamException {
out.writeEntityRef(name);
afterData();
}
public void writeEndElement() throws XMLStreamException {
beforeEndElement();
out.writeEndElement();
afterEndElement();
}
public void writeEndDocument() throws XMLStreamException {
try {
while (depth > 0) {
writeEndElement(); // indented
}
} catch (Exception ignored) {
}
out.writeEndDocument();
afterEndDocument();
}
/** Prepare to write markup, by writing a new line and indentation. */
protected void beforeMarkup() {
int soFar = stack[depth];
if ((soFar & WROTE_DATA) == 0 // no data in this scope
&& (depth > 0 || soFar != 0)) // not the first line
{
try {
writeNewLine(depth);
if (depth > 0 && getIndent().length() > 0) {
afterMarkup(); // indentation was written
}
} catch (Exception e) {
}
}
}
/** Note that markup or indentation was written. */
protected void afterMarkup() {
stack[depth] |= WROTE_MARKUP;
}
/** Note that data were written. */
protected void afterData() {
stack[depth] |= WROTE_DATA;
}
/** Prepare to start an element, by allocating stack space. */
protected void beforeStartElement() {
beforeMarkup();
if (stack.length <= depth + 1) {
// Allocate more space for the stack:
int[] newStack = new int[stack.length * 2];
System.arraycopy(stack, 0, newStack, 0, stack.length);
stack = newStack;
}
stack[depth + 1] = 0; // nothing written yet
}
/** Note that an element was started. */
protected void afterStartElement() {
afterMarkup();
++depth;
}
/** Prepare to end an element, by writing a new line and indentation. */
protected void beforeEndElement() {
if (depth > 0 && stack[depth] == WROTE_MARKUP) { // but not data
try {
writeNewLine(depth - 1);
} catch (Exception ignored) {
}
}
}
/** Note that an element was ended. */
protected void afterEndElement() {
if (depth > 0) {
--depth;
}
}
/** Note that a document was ended. */
protected void afterEndDocument() {
if (stack[depth = 0] == WROTE_MARKUP) { // but not data
try {
writeNewLine(0);
} catch (Exception ignored) {
}
}
stack[depth] = 0; // start fresh
}
/** Write a line separator followed by indentation. */
protected void writeNewLine(int indentation) throws XMLStreamException {
final int newLineLength = getNewLine().length();
final int prefixLength = newLineLength + (getIndent().length() * indentation);
if (prefixLength > 0) {
if (linePrefix == null) {
linePrefix = (getNewLine() + getIndent()).toCharArray();
}
while (prefixLength > linePrefix.length) {
// make linePrefix longer:
char[] newPrefix = new char[newLineLength
+ ((linePrefix.length - newLineLength) * 2)];
System.arraycopy(linePrefix, 0, newPrefix, 0, linePrefix.length);
System.arraycopy(linePrefix, newLineLength, newPrefix, linePrefix.length,
linePrefix.length - newLineLength);
linePrefix = newPrefix;
}
out.writeCharacters(linePrefix, 0, prefixLength);
}
}
}