com.topologi.diffx.format.StrictXMLFormatter Maven / Gradle / Ivy
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/*
* This file is part of the DiffX library.
*
* For licensing information please see the file license.txt included in the release.
* A copy of this licence can also be found at
* http://www.opensource.org/licenses/artistic-license-2.0.php
*/
package com.topologi.diffx.format;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
import java.util.Enumeration;
import com.topologi.diffx.config.DiffXConfig;
import com.topologi.diffx.event.AttributeEvent;
import com.topologi.diffx.event.CloseElementEvent;
import com.topologi.diffx.event.DiffXEvent;
import com.topologi.diffx.event.OpenElementEvent;
import com.topologi.diffx.event.impl.CharEvent;
import com.topologi.diffx.event.impl.SpaceEvent;
import com.topologi.diffx.event.impl.WordEvent;
import com.topologi.diffx.sequence.PrefixMapping;
import com.topologi.diffx.util.Constants;
/**
* A simple XML formatter that writes strictly what it is given.
*
* This formatter will write the events exactly in the order in which they are given,
* in other words, there is no way to prevent this class from writing malformed XML.
* On other hand, the {@link com.topologi.diffx.format.SmartXMLFormatter} will close
* XML elements automatically, therefore rectifying a lot of the errors that lead to
* malformed XML.
*
* @author Christophe Lauret
* @version 3 April 2005
*/
public final class StrictXMLFormatter implements XMLDiffXFormatter {
// class attributes ---------------------------------------------------------------------------
/**
* Thw output goes here.
*/
private final PrintWriter xml;
/**
* The open 'del' tag, that is the element start tag that we put before test is being deleted.
*/
private String openDel = "";
/**
* The close 'del' tag, that is the element end tag that we put after test is being deleted.
*/
private String closeDel = "";
/**
* The open 'ins' tag, that is the element start tag that we put before test is being inserted.
*/
private String openIns = "";
/**
* The close 'ins' tag, that is the element end tag that we put after test is being inserted.
*/
private String closeIns = "";
/**
* The DiffX configuration to use
*/
private DiffXConfig config = new DiffXConfig();
// state variables ----------------------------------------------------------------------------
/**
* Set to false once the prefix mapping has been declared.
*
*
* xmlns:dfx="http://www.allette.com.au/diffex"
*
*/
private transient boolean declareNamespace = true;
/**
* Set to true to indicate that there is an open 'ins' tag.
*/
private transient boolean isInserting = false;
/**
* Set to true to indicate that there is an open 'del' tag.
*/
private transient boolean isDeleting = false;
/**
* Set to true to indicate that there is an open element tag
* that does not have its right angle bracket.
*/
private transient boolean isElementNude = false;
// constructors -------------------------------------------------------------------------------
/**
* Creates a new formatter on the standard output.
*/
public StrictXMLFormatter() {
this.xml = new PrintWriter(System.out);
init();
}
/**
* Creates a new formatter using the specified writer.
*
* @param w The writer to use.
*/
public StrictXMLFormatter(Writer w) {
this.xml = new PrintWriter(w);
init();
}
// methods ------------------------------------------------------------------------------------
/**
* Writes the XML declaration.
*/
private void init() {
this.xml.println("");
}
@Override
public void format(DiffXEvent e) throws IOException {
// an element to open
if (e instanceof OpenElementEvent) {
if (this.isElementNude) {
denudeElement();
}
// close any ins / del tag
if (this.isInserting) {
closeIns();
}
if (this.isDeleting) {
closeDel();
}
OpenElementEvent oee = (OpenElementEvent)e;
this.xml.print('<'+oee.getName());
if (this.declareNamespace) {
this.xml.print(" xmlns:dfx=\""+Constants.BASE_NS_URI+"\"");
this.declareNamespace = false;
}
this.isElementNude = true;
// an element to close
} else if (e instanceof CloseElementEvent) {
if (this.isElementNude) {
denudeElement();
}
// close any ins / del tag
if (this.isInserting) {
closeIns();
}
if (this.isDeleting) {
closeDel();
}
this.xml.print(e.toXML());
// an attribute
} else if (e instanceof AttributeEvent) {
if (this.isElementNude) {
this.xml.print(e.toXML());
} else
throw new IllegalStateException("Cannot write an attribute once the element is closed");
// this is text
} else {
// close any ins / del tag
if (this.isElementNude) {
denudeElement();
}
if (this.isInserting) {
closeIns();
}
if (this.isDeleting) {
closeDel();
}
// a character sequence
if (e instanceof WordEvent || e instanceof SpaceEvent) {
this.xml.print(e.toXML());
// a single character
} else if (e instanceof CharEvent) {
this.xml.print(((CharEvent)e).c);
}
}
this.xml.flush();
}
@Override
public void insert(DiffXEvent e) throws IOException {
// insert element
if (e instanceof OpenElementEvent) {
if (this.isElementNude) {
denudeElement();
}
if (this.isDeleting) {
closeDel();
}
OpenElementEvent oee = (OpenElementEvent)e;
this.xml.print('<'+oee.getName());
if (this.declareNamespace) {
this.xml.print(" xmlns:dfx=\"http://www.allette.com.au/diffex\"");
}
this.xml.print(" dfx:insert=\"true\"");
this.isElementNude = true;
// an element to close
} else if (e instanceof CloseElementEvent) {
if (this.isElementNude) {
denudeElement();
}
if (this.isDeleting) {
closeDel();
}
this.xml.print("');
} else if (e instanceof AttributeEvent) {
if (this.isElementNude) {
this.xml.print(" ");
this.xml.print(((AttributeEvent)e).getName());
this.xml.print("=\"");
this.xml.print(((AttributeEvent)e).getValue());
this.xml.print('"');
} else {
throw new IllegalStateException("Cannot insert an attribute once the element is closed");
}
} else {
// close any del tag
if (this.isElementNude) {
denudeElement();
}
if (this.isDeleting) {
closeDel();
}
// a word
if (e instanceof WordEvent) {
if (!this.isInserting) {
openIns();
}
this.xml.print(e.toXML());
// a white space
} else if (e instanceof SpaceEvent) {
this.xml.print(e.toXML());
// wrap the char in a element
} else if (e instanceof CharEvent) {
this.xml.print(((CharEvent)e).c);
}
}
this.xml.flush();
}
@Override
public void delete(DiffXEvent e) throws IOException, IllegalStateException {
// we ignore delete attributes
if (this.isElementNude) {
denudeElement();
}
if (this.isInserting) {
closeIns();
}
// delete an element
if (e instanceof OpenElementEvent) {
OpenElementEvent oee = (OpenElementEvent)e;
this.xml.print('<'+oee.getName());
if (this.declareNamespace) {
this.xml.print(" xmlns:dfx=\"http://www.allette.com.au/diffex\"");
}
this.xml.print(" dfx:delete=\"true\"");
this.xml.print('>');
// an element to close
} else if (e instanceof CloseElementEvent) {
this.xml.print("');
// text
} else {
// a word
if (e instanceof WordEvent) {
if (!this.isDeleting) {
openDel();
}
this.xml.print(e.toXML());
// a white space
} else if (e instanceof SpaceEvent) {
this.xml.print(e.toXML());
// wrap the char in a element
} else if (e instanceof CharEvent) {
this.xml.print(((CharEvent)e).c);
}
}
this.xml.flush();
}
/**
* Sets the open and end tags for inserted text.
*
* The default values are "<ins:>" and "</ins:>" respectively.
*
* @param start The open tag for inserts.
* @param end The close tag for inserts.
*
* @throws NullPointerException If any of the tags is null.
*/
public void setInsertTags(String start, String end) throws NullPointerException {
if (start == null)
throw new NullPointerException("The start element for inserted text must have a value");
if (end == null)
throw new NullPointerException("The start element for inserted text must have a value");
this.openIns = start;
this.closeIns = end;
}
/**
* Sets the open and end tags for deleted text.
*
*
The default values are "<del:>" and "</del:>" respectively.
*
* @param start The open tag for deletions.
* @param end The close tag for deletions.
*
* @throws NullPointerException If any of the tags is null.
*/
public void setDeleteTags(String start, String end) throws NullPointerException {
if (start == null)
throw new NullPointerException("The start element for deleted text must have a value");
if (end == null)
throw new NullPointerException("The start element for deleted text must have a value");
this.openDel = start;
this.closeDel = end;
}
@Override
public void setConfig(DiffXConfig config) {
this.config = config;
}
@Override
public void setWriteXMLDeclaration(boolean show) {
}
/**
* Adds the prefix mapping to this class.
*
* @param mapping The prefix mapping to add.
*/
@Override
public void declarePrefixMapping(PrefixMapping mapping) {
for (Enumeration uris = mapping.getURIs(); uris.hasMoreElements();) {
String uri = uris.nextElement();
mapping.getPrefix(uri);
// TODO: does nothing !!!
}
}
// private helpers ----------------------------------------------------------------------------
/**
* Opens the 'ins' element, and update the state flags.
*/
private void openIns() {
this.xml.print(this.openIns);
this.isInserting = true;
}
/**
* Opens the 'del' element, and update the state flags.
*/
private void openDel() {
this.xml.print(this.openDel);
this.isDeleting = true;
}
/**
* Closes the 'ins' element, and update the state flags.
*/
private void closeIns() {
this.xml.print(this.closeIns);
this.isInserting = false;
}
/**
* Closes the 'del' element, and update the state flags.
*/
private void closeDel() {
this.xml.print(this.closeDel);
this.isDeleting = false;
}
/**
* Closes the 'del' element, and update the state flags.
*/
private void denudeElement() {
this.xml.print(">");
this.isElementNude = false;
}
}