/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cocoon.transformation;
import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import java.util.LinkedList;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.transformation.AbstractSAXTransformer;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.excalibur.source.SourceValidity;
import org.apache.excalibur.source.impl.validity.NOPValidity;
/**
* Cleanup transformer: Removes excess whitespace while adding some where needed
* for legibility. Strips unwanted namespace declarations.
*
* <p>The cleanup transformer can be used for basically any document as-is or customized by
* schema (inline vs. block elements) for easier reading.</p>
*
* <p>Transformer declaration:
* <map:components>
* <map:transformers>
* <map:transformer name="htmlcleanup"
* src="org.apache.cocoon.transformation.CleanupTransformer">
* <preserve-uri>*</preserve-uri>
* </map:transformer>
*
* <map:transformer name="xhtmlcleanup"
* src="org.apache.cocoon.transformation.CleanupTransformer">
* <inline-elements>a,abbr,acronym,b,br,font,i,u,img</inline-elements>
* <preserve-uri>http://www.w3.org/1999/xhtml</preserve-uri>
* </map:transformer>
* </map:transformers>
* </map:components>
* </p>
*
* <p>The "inline-elements" configuration element refers to a list of element names that are
* <strong>not</strong> to be indented. The "preserve-uri" configuration element specifies a
* namespace uri mapping that is meant for output. All other namespace declarations are
* stripped from the output. The "preserve-uri" element may appear more than once. If
* "preserve-uri" is omitted, all namespaces/prefixes are removed from the output.</p>
*
* <p>Transformer usage:
* <transform type="xhtmlcleanup">
* <map:parameter name="indent-size" value="4"/>
* </transform>
* </p>
*
* <p>The optional parameter "indent-size" specifies the number of additional space characters
* appearing at each level of the output document. The default value is 2.</p>
*
* <p>Bugs: Nested namespace declarations with the same namespace prefix will break the code.</p>
*
* @author Miles Elam
*/
public class CleanupTransformer
extends AbstractSAXTransformer
implements CacheableProcessingComponent {
private static final char[] INDENT = ("\n" +
" " +
" "
).toCharArray();
private static final int MAX_INDENT = CleanupTransformer.INDENT.length - 1;
private boolean allowAllURIs = false;
private Set allowedURIs = new HashSet();
private Set inlineElements = new HashSet();
private LinkedList uriPrefixes = new LinkedList();
private int indentSize = 2;
private int numIndents = 0;
private String lastElement;
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#configure(org.apache.avalon.framework.configuration.Configuration)
*/
public void configure(Configuration conf)
throws ConfigurationException {
StringTokenizer st;
Configuration inlineEltChild = conf.getChild("inline-elements");
st = new StringTokenizer(inlineEltChild.getValue(""), ",");
this.inlineElements.clear();
while (st.hasMoreTokens()) {
String nextElement = st.nextToken().trim();
if (nextElement.length() > 0) {
this.inlineElements.add(nextElement);
}
}
this.allowAllURIs = false;
Configuration[] uriChildren = conf.getChildren("preserve-uri");
for (int i=0; i<uriChildren.length; ++i) {
String nextChild = uriChildren[i].getValue("").trim();
if (nextChild.length() == 0) {
continue;
} else if (nextChild.equals("*")) {
this.allowAllURIs = true;
break;
}
this.allowedURIs.add(nextChild);
}
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#setup(org.apache.cocoon.environment.SourceResolver, java.util.Map, java.lang.String, org.apache.avalon.framework.parameters.Parameters)
*/
public void setup (SourceResolver resolver, Map objectModel, String src, Parameters par)
throws ProcessingException, SAXException, IOException {
super.setup(resolver, objectModel, src, par);
this.indentSize = par.getParameterAsInteger("indent-size", 2);
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#recycle()
*/
public void recycle () {
super.recycle();
this.numIndents = 0;
this.lastElement = null;
this.uriPrefixes.clear();
}
/**
* @see org.apache.cocoon.caching.CacheableProcessingComponent#getKey()
*/
public Serializable getKey () {
return Integer.toString(this.indentSize);
}
/**
* @see org.apache.cocoon.caching.CacheableProcessingComponent#getValidity()
*/
public SourceValidity getValidity () {
return NOPValidity.SHARED_INSTANCE;
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#startPrefixMapping(java.lang.String, java.lang.String)
*/
public void startPrefixMapping (String prefix, String uri)
throws SAXException {
if (this.allowAllURIs) {
this.contentHandler.startPrefixMapping(prefix, uri);
} else if (this.allowedURIs.contains(uri)) {
this.contentHandler.startPrefixMapping(prefix, uri);
uriPrefixes.add(prefix);
}
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#endPrefixMapping(java.lang.String)
*/
public void endPrefixMapping (String prefix)
throws SAXException {
if (this.allowAllURIs) {
this.contentHandler.endPrefixMapping(prefix);
} else if (!uriPrefixes.isEmpty()) {
if (uriPrefixes.getLast().toString().equals(prefix)) {
this.contentHandler.endPrefixMapping(prefix);
uriPrefixes.removeLast();
}
}
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
*/
public void startElement (String uri, String qName, String lName, Attributes attrs)
throws SAXException {
if (!inlineElements.contains(qName)) {
int indentSize = (this.indentSize * this.numIndents) % MAX_INDENT;
this.contentHandler.ignorableWhitespace(INDENT, 0, indentSize + 1);
++this.numIndents;
this.lastElement = qName;
}
this.contentHandler.startElement(uri, qName, lName, attrs);
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#endElement(java.lang.String, java.lang.String, java.lang.String)
*/
public void endElement (String uri, String qName, String lName)
throws SAXException {
if (!inlineElements.contains(qName)) {
--this.numIndents;
if (this.lastElement == null || !this.lastElement.equals(qName)) {
int indentSize = (this.indentSize * this.numIndents) % MAX_INDENT;
this.contentHandler.ignorableWhitespace(INDENT, 0, indentSize + 1);
}
this.lastElement = null;
}
this.contentHandler.endElement(uri, qName, lName);
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#characters(char[], int, int)
*/
public void characters (char[] ch, int start, int length)
throws SAXException {
int end = start + length;
for (int i=start; i<end; ++i) {
if (!Character.isWhitespace(ch[i])) {
this.contentHandler.characters(ch, start, length);
return;
}
}
this.contentHandler.characters(INDENT, 1, 1);
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#ignorableWhitespace(char[], int, int)
*/
public void ignorableWhitespace (char[] ch, int start, int length)
throws SAXException {
// Do nothing
}
}