/*
* 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.config.WhiteSpaceProcessing;
import com.topologi.diffx.event.AttributeEvent;
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.CharactersEventBase;
import com.topologi.diffx.event.impl.SpaceEvent;
import com.topologi.diffx.sequence.PrefixMapping;
import com.topologi.diffx.util.Constants;
import com.topologi.diffx.xml.XMLWriter;
import com.topologi.diffx.xml.XMLWriterNSImpl;
/**
* An XML formatter that tries to ensure that the output XML will be well-formed.
*
* <p>This class will always close the elements correctly by maintaining a stack of parent elements.
*
* <p>Implementation note: this classes uses the namespace prefixes 'dfx' and 'del', in the
* future it should be possible to configure which prefixes to use for each namespace, but
* in this version the namespace prefix mapping is hard-coded.
*
* @author Christophe Lauret
* @version 11 May 2010
*/
public final class SafeXMLFormatter implements XMLDiffXFormatter {
/**
* Set to <code>true</code> to show debug info.
*/
private static final boolean DEBUG = false;
// class attributes ---------------------------------------------------------------------------
/**
* The output goes here.
*/
private final XMLWriter xml;
/**
* The DiffX configuration to use
*/
private DiffXConfig config = new DiffXConfig();
// state variables ----------------------------------------------------------------------------
/**
* Set to <code>true</code> to include the XML declaration.
*
* <p>This attribute is set to <code>false</code> when the {@link #setWriteXMLDeclaration(boolean)}
* is called with <code>false</code> or once the XML declaration has been written.
*/
private transient boolean writeXMLDeclaration = true;
// constructors -------------------------------------------------------------------------------
/**
* Creates a new formatter on the standard output.
*
* <p>This constructor is equivalent to:
* <pre>new SmartXMLFormatter(new PrintWriter(System.out));</pre>.
*
* @see System#out
*
* @throws IOException should an I/O exception occurs.
*/
public SafeXMLFormatter() throws IOException {
this(new PrintWriter(System.out));
}
/**
* Creates a new formatter using the specified writer.
*
* @param w The writer to use.
*
* @throws IOException should an I/O exception occurs.
*/
public SafeXMLFormatter(Writer w) throws IOException {
this.xml = new XMLWriterNSImpl(w, false);
if (this.writeXMLDeclaration) {
this.xml.xmlDecl();
this.writeXMLDeclaration = false;
}
this.xml.setPrefixMapping(Constants.BASE_NS_URI, "dfx");
this.xml.setPrefixMapping(Constants.DELETE_NS_URI, "del");
this.xml.setPrefixMapping(Constants.INSERT_NS_URI, "ins");
}
// methods ------------------------------------------------------------------------------------
@Override
public void format(DiffXEvent e) throws IOException {
if (DEBUG) {
System.err.println("="+e);
}
e.toXML(this.xml);
if (e instanceof CharactersEventBase)
if (this.config.getWhiteSpaceProcessing() == WhiteSpaceProcessing.IGNORE) {
this.xml.writeXML(" ");
}
this.xml.flush();
}
@Override
public void insert(DiffXEvent e) throws IOException {
if (DEBUG) {
System.err.println("+"+e);
}
// insert an attribute to specify
if (e instanceof OpenElementEvent) {
e.toXML(this.xml);
this.xml.attribute("dfx:insert", "true");
// just output the new line
} else if (e == SpaceEvent.NEW_LINE) {
e.toXML(this.xml);
// wrap the characters in a <ins> element
} else if (e instanceof CharactersEventBase) {
this.xml.openElement(Constants.BASE_NS_URI, "ins", false); //this.xml.openElement("ins", false);
e.toXML(this.xml);
this.xml.closeElement();
if (this.config.getWhiteSpaceProcessing() == WhiteSpaceProcessing.IGNORE) {
this.xml.writeXML(" ");
}
// display the attribute normally
} else if (e instanceof AttributeEvent) {
e.toXML(this.xml);
this.xml.attribute("ins:"+((AttributeEvent)e).getName(), "true");
// wrap the char in a <ins> element
} else if (e instanceof CharEvent) {
this.xml.openElement(Constants.BASE_NS_URI, "ins", false); //this.xml.openElement("ins", false);
e.toXML(this.xml);
this.xml.closeElement();
// just format naturally
} else {
e.toXML(this.xml);
}
this.xml.flush();
}
@Override
public void delete(DiffXEvent e) throws IOException {
if (DEBUG) {
System.err.println("-"+e);
}
// insert an attribute to specify
if (e instanceof OpenElementEvent) {
e.toXML(this.xml);
this.xml.attribute("dfx:delete", "true");
// just output the new line
} else if (e == SpaceEvent.NEW_LINE) {
e.toXML(this.xml);
// wrap the characters in a <del> element
} else if (e instanceof CharactersEventBase) {
this.xml.openElement(Constants.BASE_NS_URI, "del", false); //this.xml.openElement("del", false);
e.toXML(this.xml);
this.xml.closeElement();
if (this.config.getWhiteSpaceProcessing() == WhiteSpaceProcessing.IGNORE) {
this.xml.writeXML(" ");
}
// put the attribute as part of the 'delete' namespace
} else if (e instanceof AttributeEvent) {
this.xml.attribute("del:"+((AttributeEvent)e).getName(), ((AttributeEvent)e).getValue());
// wrap the char in a <del> element
} else if (e instanceof CharEvent) {
this.xml.openElement(Constants.BASE_NS_URI, "del", false); //this.xml.openElement("del", false);
e.toXML(this.xml);
this.xml.closeElement();
// just format naturally
} else {
e.toXML(this.xml);
}
this.xml.flush();
}
@Override
public void setConfig(DiffXConfig config) {
this.config = config;
}
@Override
public void setWriteXMLDeclaration(boolean show) {
this.writeXMLDeclaration = show;
}
/**
* Adds the prefix mapping to this class.
*
* @param mapping The prefix mapping to add.
*/
@Override
public void declarePrefixMapping(PrefixMapping mapping) {
for (Enumeration<String> uris = mapping.getURIs(); uris.hasMoreElements();) {
String uri = uris.nextElement();
this.xml.setPrefixMapping(uri, mapping.getPrefix(uri));
}
}
}