_br-ode-1.X.svn/utils/src/main/java/org/apache/ode/utils/NamespaceStack.java - ode - Git at Google

 /*
  * 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.ode.utils;

 import java.util.EmptyStackException;
 import java.util.HashMap;
 import java.util.Iterator;

 import javax.xml.namespace.QName;

 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;


 /**
  * <p>
  * This is a utility for a SAX <code>ContentHandler</code> implementation to use in
  * tracking namespace declarations during a parse.  The assumption is that the
  * handler has access to the full stream of events relevant to managing the
  * declarations.  The primary use case is the resolution of <code>String</code>s,
  * e.g., from attribute values or element content, to <code>QName</code> objects.
  * </p>
  */
 public class NamespaceStack {

   private Frame _current;

   /**
    * <p>
    * Construct a new instance with the bare minimum bindings for the
    * <code>xmlns</code>, <code>xml</code>, and empty prefixes.  Note that the empty
    * prefix is bound to the empty (non-<code>null</code>) URI.
    * </p>
    */
   public NamespaceStack() {
     _current = new Frame();
     /*
      * As per the Namespaces in XML Errata:
      * http://www.w3.org/XML/xml-names-19990114-errata
      */
     _current.declarePrefix("xmlns","http://www.w3.org/2000/xmlns/");
     /*
      * As per the Namespaces in XML Rec:
      * http://www.w3.org/TR/1999/REC-xml-names-19990114
      */
     _current.declarePrefix("xml","http://www.w3.org/XML/1998/namespace");
     /*
      * As per the Namespaces in XML Rec:
      * http://www.w3.org/TR/1999/REC-xml-names-19990114
      */
     _current.declarePrefix("","");
   }

   /**
    * <p>
    * Convert the current stack of contexts into a single <code>NSContext</code>.
    * </p>
    * @return the <code>NSContext</code> instance
    */
   public NSContext toNSContext() {
     NSContext n = new NSContext();
     for (Frame f = _current;f != null; f=f._parent) {
       if (f._bindings == null) continue;
       for (Iterator it = f._bindings.keySet().iterator();it.hasNext();) {
         String pfx = (String) it.next();
         if (n.getNamespaceURI(pfx) == null) {
           n.register(pfx, f._bindings.get(pfx));
         }
       }
     }
     return n;
   }

   /**
    * <p>
    * Push a fresh context onto the stack.  This method should be called somewhere in
    * the body of a <code>startElement()</code>, as it represents the namespace
    * resolution context for the events that occur between that event and the
    * corresponding <code>endElement()</code>.
    * </p>
    * @see org.xml.sax.ContentHandler
    */
   public void pushNewContext() {
     _current = new Frame(_current);
   }

   /**
    * <p>
    * Pop a context from the stack.  This method should be called somewhere in the
    * body of an <code>endElement</code>, as it clears the context that was used for
    * namespace resolution within the body of the corresponding element.
    * </p>
    * @see org.xml.sax.ContentHandler
    */
   public void pop() {
     if (_current._parent == null) {
       throw new EmptyStackException();
     }
     _current = _current._parent;
   }

   /**
    * <p>
    * Declare a new prefix binding.  This binding will supercede a binding with the
    * same prefix in the same scope.  As a crutch, <code>null</code> arguments may be
    * passed and will be interpreted as <code>&quot;&quot;</code>.  Note that binding
    * a non-empty prefix to an empty URI is not permitted in XML 1.0 but is not
    * flagged as an error by the method.
    * </p>
    * @param prefix the prefix to bind
    * @param uri the URI to bind it to
    */
   public void declarePrefix(String prefix, String uri) {
     _current.declarePrefix(prefix==null?"":prefix, uri==null?"":uri);
   }

   /**
    * <p>
    * Retrieve the URI bound to the supplied prefix or <code>null</code> if no URI
    * is bound to the supplied prefix.  As a crutch, a <code>null</code> argument
    * may be passed and will be interpreted as the empty prefix
    * (<code>&quot;&quot;</code>).
    * </p>
    * @returns the URI or <code>null</code> if no URI is bound.
    */
   public String getNamespaceUri(String prefix) {
     return _current.getNamespaceURI(prefix==null?"":prefix);
   }

   /**
    * <p>
    * Fire the events for the current frame's prefixes into a <code>ContentHandler</code>.
    * </p>
    * @param ch the target <code>ContentHandler</code>
    * @throws SAXException if the target method does.
    */
   public void startPrefixMappings(ContentHandler ch) throws SAXException {
     _current.startPrefixMappings(ch);
   }

   /**
    * <p>
    * Fire the events for the current frame's prefixes into a <code>ContentHandler</code>.
    * </p>
    * @param ch the target <code>ContentHandler</code>.
    * @throws SAXException if the target method does.
    */
   public void endPrefixMappings(ContentHandler ch) throws SAXException {
     _current.endPrefixMappings(ch);
   }

   /**
    * <p>
    * Allocate and declare a new namespace prefix for the current context that uses
    * the supplied &quot;hint&quot; as a start.  The algorithm used will defer to an
    * existing binding, then try the hint, then use a variant of the hint until it
    * finds an available prefix.
    * </p>
    * @param hint a hint as to the desired prefix or <code>null</code> if any prefix
    * will do.
    * @param uri the URI to bind to the prefix.
    * @return the suggested prefix.
    */
   public String allocatePrefix(String hint, String uri) {
     String pfx = getPrefix(uri);
     if (pfx == null) {
       hint = hint==null?"ns":hint;
       String u = getNamespaceUri(hint);
       if (u == null) {
         declarePrefix(hint,uri);
         pfx = hint;
       } else if (u.equals(uri)) {
         pfx = hint;
       } else {
         // ??
       }
     }
     return pfx;
   }

   public String getPrefix(String uri) {
     return toNSContext().getPrefix(uri);
   }

   /**
    * <p>
    * Derference the prefix on a QName in <code>String</code> form and return a Java
    * <code>QName</code> object.
    * </p>
    * @param qname the QName in string form.
    * @return the dereferenced <code>QName</code>.
    * @throws IllegalArgumentException if a <code>null</code> argument is passed,
    * a malformed argument (e.g., <code>:foo</code> or <code>foo:</code>) is passed,
    * or if the prefix cannot be resolved to a URI.
    */
   public QName dereferenceQName(String qname) {
     if (qname == null) {
       throw new IllegalArgumentException("Unable to dereference <null> as a QName.");
     }
     int pos = qname.indexOf(':');
     QName qn;
     if (pos == qname.length() - 1 || pos == 0) {
       throw new IllegalArgumentException("\"" + qname + "\" is a malformed QName.");
     } else if (pos == -1) {
       qn = new QName (getNamespaceUri(""),qname);
     } else {
       String uri = getNamespaceUri(qname.substring(0,pos));
       if (uri == null) {
         throw new IllegalArgumentException("No URI is bound to " +
             qname.substring(0,pos) + ".");
       }
       qn = new QName(uri,qname.substring(pos+1));
     }
     return qn;
   }

   private class Frame {

     Frame _parent;

     HashMap<String,String> _bindings;

     Frame() {
       // This space intentionally left blank.
     }

     Frame(Frame parent) {
       _parent = parent;
     }

     void startPrefixMappings(ContentHandler ch) throws SAXException {
       if (_bindings != null) {
         for(Iterator it = _bindings.keySet().iterator();it.hasNext();) {
           String prefix = (String) it.next();
           ch.startPrefixMapping(prefix, _bindings.get(prefix));
         }
       }
     }

     void endPrefixMappings(ContentHandler ch) throws SAXException {
       if (_bindings != null) {
         for (Iterator it = _bindings.keySet().iterator();it.hasNext();) {
           ch.endPrefixMapping((String) it.next());
         }
       }
     }

     void declarePrefix(String prefix, String uri) {
       if (_bindings == null) {
         _bindings = new HashMap<String,String>();
       }
       _bindings.put(prefix,uri);
     }

     String getPrefix(String uri) {
       return "";
     }


     String getNamespaceURI(String prefix) {
       String uri = null;
       if (_bindings != null) {
         uri = _bindings.get(prefix);
       }
       if (uri == null) {
         uri= _parent==null ? null:(_parent.getNamespaceURI(prefix));
       }
       return uri;
     }

   }
 }
	/*
	* 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.ode.utils;

	import java.util.EmptyStackException;
	import java.util.HashMap;
	import java.util.Iterator;

	import javax.xml.namespace.QName;

	import org.xml.sax.ContentHandler;
	import org.xml.sax.SAXException;


	/**
	* <p>
	* This is a utility for a SAX <code>ContentHandler</code> implementation to use in
	* tracking namespace declarations during a parse. The assumption is that the
	* handler has access to the full stream of events relevant to managing the
	* declarations. The primary use case is the resolution of <code>String</code>s,
	* e.g., from attribute values or element content, to <code>QName</code> objects.
	* </p>
	*/
	public class NamespaceStack {

	private Frame _current;

	/**
	* <p>
	* Construct a new instance with the bare minimum bindings for the
	* <code>xmlns</code>, <code>xml</code>, and empty prefixes. Note that the empty
	* prefix is bound to the empty (non-<code>null</code>) URI.
	* </p>
	*/
	public NamespaceStack() {
	_current = new Frame();
	/*
	* As per the Namespaces in XML Errata:
	* http://www.w3.org/XML/xml-names-19990114-errata
	*/
	_current.declarePrefix("xmlns","http://www.w3.org/2000/xmlns/");
	/*
	* As per the Namespaces in XML Rec:
	* http://www.w3.org/TR/1999/REC-xml-names-19990114
	*/
	_current.declarePrefix("xml","http://www.w3.org/XML/1998/namespace");
	/*
	* As per the Namespaces in XML Rec:
	* http://www.w3.org/TR/1999/REC-xml-names-19990114
	*/
	_current.declarePrefix("","");
	}

	/**
	* <p>
	* Convert the current stack of contexts into a single <code>NSContext</code>.
	* </p>
	* @return the <code>NSContext</code> instance
	*/
	public NSContext toNSContext() {
	NSContext n = new NSContext();
	for (Frame f = _current;f != null; f=f._parent) {
	if (f._bindings == null) continue;
	for (Iterator it = f._bindings.keySet().iterator();it.hasNext();) {
	String pfx = (String) it.next();
	if (n.getNamespaceURI(pfx) == null) {
	n.register(pfx, f._bindings.get(pfx));
	}
	}
	}
	return n;
	}

	/**
	* <p>
	* Push a fresh context onto the stack. This method should be called somewhere in
	* the body of a <code>startElement()</code>, as it represents the namespace
	* resolution context for the events that occur between that event and the
	* corresponding <code>endElement()</code>.
	* </p>
	* @see org.xml.sax.ContentHandler
	*/
	public void pushNewContext() {
	_current = new Frame(_current);
	}

	/**
	* <p>
	* Pop a context from the stack. This method should be called somewhere in the
	* body of an <code>endElement</code>, as it clears the context that was used for
	* namespace resolution within the body of the corresponding element.
	* </p>
	* @see org.xml.sax.ContentHandler
	*/
	public void pop() {
	if (_current._parent == null) {
	throw new EmptyStackException();
	}
	_current = _current._parent;
	}

	/**
	* <p>
	* Declare a new prefix binding. This binding will supercede a binding with the
	* same prefix in the same scope. As a crutch, <code>null</code> arguments may be
	* passed and will be interpreted as <code>""</code>. Note that binding
	* a non-empty prefix to an empty URI is not permitted in XML 1.0 but is not
	* flagged as an error by the method.
	* </p>
	* @param prefix the prefix to bind
	* @param uri the URI to bind it to
	*/
	public void declarePrefix(String prefix, String uri) {
	_current.declarePrefix(prefix==null?"":prefix, uri==null?"":uri);
	}

	/**
	* <p>
	* Retrieve the URI bound to the supplied prefix or <code>null</code> if no URI
	* is bound to the supplied prefix. As a crutch, a <code>null</code> argument
	* may be passed and will be interpreted as the empty prefix
	* (<code>""</code>).
	* </p>
	* @returns the URI or <code>null</code> if no URI is bound.
	*/
	public String getNamespaceUri(String prefix) {
	return _current.getNamespaceURI(prefix==null?"":prefix);
	}

	/**
	* <p>
	* Fire the events for the current frame's prefixes into a <code>ContentHandler</code>.
	* </p>
	* @param ch the target <code>ContentHandler</code>
	* @throws SAXException if the target method does.
	*/
	public void startPrefixMappings(ContentHandler ch) throws SAXException {
	_current.startPrefixMappings(ch);
	}

	/**
	* <p>
	* Fire the events for the current frame's prefixes into a <code>ContentHandler</code>.
	* </p>
	* @param ch the target <code>ContentHandler</code>.
	* @throws SAXException if the target method does.
	*/
	public void endPrefixMappings(ContentHandler ch) throws SAXException {
	_current.endPrefixMappings(ch);
	}

	/**
	* <p>
	* Allocate and declare a new namespace prefix for the current context that uses
	* the supplied "hint" as a start. The algorithm used will defer to an
	* existing binding, then try the hint, then use a variant of the hint until it
	* finds an available prefix.
	* </p>
	* @param hint a hint as to the desired prefix or <code>null</code> if any prefix
	* will do.
	* @param uri the URI to bind to the prefix.
	* @return the suggested prefix.
	*/
	public String allocatePrefix(String hint, String uri) {
	String pfx = getPrefix(uri);
	if (pfx == null) {
	hint = hint==null?"ns":hint;
	String u = getNamespaceUri(hint);
	if (u == null) {
	declarePrefix(hint,uri);
	pfx = hint;
	} else if (u.equals(uri)) {
	pfx = hint;
	} else {
	// ??
	}
	}
	return pfx;
	}

	public String getPrefix(String uri) {
	return toNSContext().getPrefix(uri);
	}

	/**
	* <p>
	* Derference the prefix on a QName in <code>String</code> form and return a Java
	* <code>QName</code> object.
	* </p>
	* @param qname the QName in string form.
	* @return the dereferenced <code>QName</code>.
	* @throws IllegalArgumentException if a <code>null</code> argument is passed,
	* a malformed argument (e.g., <code>:foo</code> or <code>foo:</code>) is passed,
	* or if the prefix cannot be resolved to a URI.
	*/
	public QName dereferenceQName(String qname) {
	if (qname == null) {
	throw new IllegalArgumentException("Unable to dereference <null> as a QName.");
	}
	int pos = qname.indexOf(':');
	QName qn;
	if (pos == qname.length() - 1 \|\| pos == 0) {
	throw new IllegalArgumentException("\"" + qname + "\" is a malformed QName.");
	} else if (pos == -1) {
	qn = new QName (getNamespaceUri(""),qname);
	} else {
	String uri = getNamespaceUri(qname.substring(0,pos));
	if (uri == null) {
	throw new IllegalArgumentException("No URI is bound to " +
	qname.substring(0,pos) + ".");
	}
	qn = new QName(uri,qname.substring(pos+1));
	}
	return qn;
	}

	private class Frame {

	Frame _parent;

	HashMap<String,String> _bindings;

	Frame() {
	// This space intentionally left blank.
	}

	Frame(Frame parent) {
	_parent = parent;
	}

	void startPrefixMappings(ContentHandler ch) throws SAXException {
	if (_bindings != null) {
	for(Iterator it = _bindings.keySet().iterator();it.hasNext();) {
	String prefix = (String) it.next();
	ch.startPrefixMapping(prefix, _bindings.get(prefix));
	}
	}
	}

	void endPrefixMappings(ContentHandler ch) throws SAXException {
	if (_bindings != null) {
	for (Iterator it = _bindings.keySet().iterator();it.hasNext();) {
	ch.endPrefixMapping((String) it.next());
	}
	}
	}

	void declarePrefix(String prefix, String uri) {
	if (_bindings == null) {
	_bindings = new HashMap<String,String>();
	}
	_bindings.put(prefix,uri);
	}

	String getPrefix(String uri) {
	return "";
	}


	String getNamespaceURI(String prefix) {
	String uri = null;
	if (_bindings != null) {
	uri = _bindings.get(prefix);
	}
	if (uri == null) {
	uri= _parent==null ? null:(_parent.getNamespaceURI(prefix));
	}
	return uri;
	}

	}
	}