- /*
- * Copyright 2003-2004 The Apache Software Foundation.
- *
- * Licensed 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.
- */
- /*
- * $Id: NamespaceMappings.java,v 1.6 2004/02/17 04:18:18 minchau Exp $
- */
- package com.sun.org.apache.xml.internal.serializer;
-
- import java.util.Enumeration;
- import java.util.Hashtable;
- import java.util.Stack;
-
- import org.xml.sax.ContentHandler;
- import org.xml.sax.SAXException;
-
- /**
- * This class keeps track of the currently defined namespaces. Conceptually the
- * prefix/uri/depth triplets are pushed on a stack pushed on a stack. The depth
- * indicates the nesting depth of the element for which the mapping was made.
- *
- * <p>For example:
- * <pre>
- * <chapter xmlns:p1="def">
- * <paragraph xmlns:p2="ghi">
- * <sentance xmlns:p3="jkl">
- * </sentance>
- * </paragraph>
- * <paragraph xlmns:p4="mno">
- * </paragraph>
- * </chapter>
- * </pre>
- *
- * When the <chapter> element is encounted the prefix "p1" associated with uri
- * "def" is pushed on the stack with depth 1.
- * When the first <paragraph> is encountered "p2" and "ghi" are pushed with
- * depth 2.
- * When the <sentance> is encountered "p3" and "jkl" are pushed with depth 3.
- * When </sentance> occurs the popNamespaces(3) will pop "p3"/"jkl" off the
- * stack. Of course popNamespaces(2) would pop anything with depth 2 or
- * greater.
- *
- * So prefix/uri pairs are pushed and poped off the stack as elements are
- * processed. At any given moment of processing the currently visible prefixes
- * are on the stack and a prefix can be found given a uri, or a uri can be found
- * given a prefix.
- */
- public class NamespaceMappings
- {
- /**
- * This member is continually incremented when new prefixes need to be
- * generated. ("ns0" "ns1" ...)
- */
- private int count = 0;
-
- /**
- * Stack of prefixes that have mappings
- * The top of this stack is the prefix that was last mapped to an URI
- *
- * For every prefix pushed on this stack a corresponding integer is pushed
- * on the m_nodeStack. That way all prefixes pushed at the current depth can
- * be removed at the same time.
- */
- private java.util.Stack m_prefixStack = new Stack();
-
- /**
- * Each entry (prefix) in this hashtable points to a Stack of URIs
- */
- private Hashtable m_namespaces = new Hashtable();
-
- /**
- * The top of this stack contains the nested element depth
- * of the last declared a namespace.
- * Used to know how many prefix mappings to pop when leaving
- * the current element depth.
- * For every prefix mapping the current element depth is
- * pushed on this stack, as well as the prefix on the m_prefixStack
- * That way all prefixes pushed at the current depth can be
- * removed at the same time.
- * Used to ensure prefix/uri map scopes are closed correctly
- *
- */
- private Stack m_nodeStack = new Stack();
-
- private static final String EMPTYSTRING = "";
- private static final String XML_PREFIX = "xml"; // was "xmlns"
-
- /**
- * Default constructor
- * @see java.lang.Object#Object()
- */
- public NamespaceMappings()
- {
- initNamespaces();
- }
-
- /**
- * This method initializes the namespace object with appropriate stacks
- * and predefines a few prefix/uri pairs which always exist.
- */
- private void initNamespaces()
- {
-
-
- // Define the default namespace (initially maps to "" uri)
- Stack stack;
- m_namespaces.put(EMPTYSTRING, stack = new Stack());
- stack.push(EMPTYSTRING);
- m_prefixStack.push(EMPTYSTRING);
-
- m_namespaces.put(XML_PREFIX, stack = new Stack());
- stack.push("http://www.w3.org/XML/1998/namespace");
- m_prefixStack.push(XML_PREFIX);
-
- m_nodeStack.push(new Integer(-1));
-
- }
-
- /**
- * Use a namespace prefix to lookup a namespace URI.
- *
- * @param prefix String the prefix of the namespace
- * @return the URI corresponding to the prefix
- */
- public String lookupNamespace(String prefix)
- {
- final Stack stack = (Stack) m_namespaces.get(prefix);
- return stack != null && !stack.isEmpty() ? (String) stack.peek() : null;
- }
-
- /**
- * Given a namespace uri, and the namespaces mappings for the
- * current element, return the current prefix for that uri.
- *
- * @param uri the namespace URI to be search for
- * @return an existing prefix that maps to the given URI, null if no prefix
- * maps to the given namespace URI.
- */
- public String lookupPrefix(String uri)
- {
- String foundPrefix = null;
- Enumeration prefixes = m_namespaces.keys();
- while (prefixes.hasMoreElements())
- {
- String prefix = (String) prefixes.nextElement();
- String uri2 = lookupNamespace(prefix);
- if (uri2 != null && uri2.equals(uri))
- {
- foundPrefix = prefix;
- break;
- }
- }
- return foundPrefix;
- }
-
- /**
- * Undeclare the namespace that is currently pointed to by a given prefix
- */
- public boolean popNamespace(String prefix)
- {
- // Prefixes "xml" and "xmlns" cannot be redefined
- if (prefix.startsWith(XML_PREFIX))
- {
- return false;
- }
-
- Stack stack;
- if ((stack = (Stack) m_namespaces.get(prefix)) != null)
- {
- stack.pop();
- return true;
- }
- return false;
- }
-
- /**
- * Declare a prefix to point to a namespace URI
- * @param prefix a String with the prefix for a qualified name
- * @param uri a String with the uri to which the prefix is to map
- * @param elemDepth the depth of current declaration
- */
- public boolean pushNamespace(String prefix, String uri, int elemDepth)
- {
- // Prefixes "xml" and "xmlns" cannot be redefined
- if (prefix.startsWith(XML_PREFIX))
- {
- return false;
- }
-
- Stack stack;
- // Get the stack that contains URIs for the specified prefix
- if ((stack = (Stack) m_namespaces.get(prefix)) == null)
- {
- m_namespaces.put(prefix, stack = new Stack());
- }
-
- if (!stack.empty() && uri.equals(stack.peek()))
- {
- return false;
- }
-
- stack.push(uri);
- m_prefixStack.push(prefix);
- m_nodeStack.push(new Integer(elemDepth));
- return true;
- }
-
- /**
- * Pop, or undeclare all namespace definitions that are currently
- * declared at the given element depth, or deepter.
- * @param elemDepth the element depth for which mappings declared at this
- * depth or deeper will no longer be valid
- * @param saxHandler The ContentHandler to notify of any endPrefixMapping()
- * calls. This parameter can be null.
- */
- public void popNamespaces(int elemDepth, ContentHandler saxHandler)
- {
- while (true)
- {
- if (m_nodeStack.isEmpty())
- return;
- Integer i = (Integer) (m_nodeStack.peek());
- if (i.intValue() < elemDepth)
- return;
- /* the depth of the declared mapping is elemDepth or deeper
- * so get rid of it
- */
-
- m_nodeStack.pop();
- final String prefix = (String) m_prefixStack.pop();
- popNamespace(prefix);
- if (saxHandler != null)
- {
- try
- {
- saxHandler.endPrefixMapping(prefix);
- }
- catch (SAXException e)
- {
- // not much we can do if they aren't willing to listen
- }
- }
-
- }
- }
-
- /**
- * Generate a new namespace prefix ( ns0, ns1 ...) not used before
- * @return String a new namespace prefix ( ns0, ns1, ns2 ...)
- */
- public String generateNextPrefix()
- {
- return "ns" + (count++);
- }
-
-
- /**
- * This method makes a clone of this object.
- *
- */
- public Object clone() throws CloneNotSupportedException {
- NamespaceMappings clone = new NamespaceMappings();
- clone.m_prefixStack = (Stack)m_prefixStack.clone();
- clone.m_nodeStack = (Stack) m_nodeStack.clone();
- clone.m_namespaces = (Hashtable) m_namespaces.clone();
-
- clone.count = count;
- return clone;
-
- }
-
- public final void reset()
- {
- this.count = 0;
- this.m_namespaces.clear();
- this.m_nodeStack.clear();
- this.m_prefixStack.clear();
-
- initNamespaces();
- }
-
- }