| /* |
| * 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. |
| */ |
| /* |
| * $Id: NamespaceSupport2.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xml.utils; |
| |
| import java.util.EmptyStackException; |
| import java.util.Enumeration; |
| import java.util.Hashtable; |
| import java.util.Vector; |
| |
| /** |
| * Encapsulate Namespace tracking logic for use by SAX drivers. |
| * |
| * <p>This class is an attempt to rewrite the SAX NamespaceSupport |
| * "helper" class for improved efficiency. It can be used to track the |
| * namespace declarations currently in scope, providing lookup |
| * routines to map prefixes to URIs and vice versa.</p> |
| * |
| * <p>ISSUE: For testing purposes, I've extended NamespaceSupport even |
| * though I'm completely reasserting all behaviors and fields. |
| * Wasteful.... But SAX did not put an interface under that object and |
| * we seem to have written that SAX class into our APIs... and I don't |
| * want to argue with it right now. </p> |
| * |
| * @see org.xml.sax.helpers.NamespaceSupport |
| * */ |
| public class NamespaceSupport2 |
| extends org.xml.sax.helpers.NamespaceSupport |
| { |
| //////////////////////////////////////////////////////////////////// |
| // Internal state. |
| //////////////////////////////////////////////////////////////////// |
| |
| private Context2 currentContext; // Current point on the double-linked stack |
| |
| |
| //////////////////////////////////////////////////////////////////// |
| // Constants. |
| //////////////////////////////////////////////////////////////////// |
| |
| |
| /** |
| * The XML Namespace as a constant. |
| * |
| * <p>This is the Namespace URI that is automatically mapped |
| * to the "xml" prefix.</p> |
| */ |
| public final static String XMLNS = |
| "http://www.w3.org/XML/1998/namespace"; |
| |
| |
| //////////////////////////////////////////////////////////////////// |
| // Constructor. |
| //////////////////////////////////////////////////////////////////// |
| |
| |
| /** |
| * Create a new Namespace support object. |
| */ |
| public NamespaceSupport2 () |
| { |
| reset(); |
| } |
| |
| |
| //////////////////////////////////////////////////////////////////// |
| // Context management. |
| //////////////////////////////////////////////////////////////////// |
| |
| |
| /** |
| * Reset this Namespace support object for reuse. |
| * |
| * <p>It is necessary to invoke this method before reusing the |
| * Namespace support object for a new session.</p> |
| */ |
| public void reset () |
| { |
| // Discarding the whole stack doesn't save us a lot versus |
| // creating a new NamespaceSupport. Do we care, or should we |
| // change this to just reset the root context? |
| currentContext = new Context2(null); |
| currentContext.declarePrefix("xml", XMLNS); |
| } |
| |
| |
| /** |
| * Start a new Namespace context. |
| * |
| * <p>Normally, you should push a new context at the beginning |
| * of each XML element: the new context will automatically inherit |
| * the declarations of its parent context, but it will also keep |
| * track of which declarations were made within this context.</p> |
| * |
| * <p>The Namespace support object always starts with a base context |
| * already in force: in this context, only the "xml" prefix is |
| * declared.</p> |
| * |
| * @see #popContext |
| */ |
| public void pushContext () |
| { |
| // JJK: Context has a parent pointer. |
| // That means we don't need a stack to pop. |
| // We may want to retain for reuse, but that can be done via |
| // a child pointer. |
| |
| Context2 parentContext=currentContext; |
| currentContext = parentContext.getChild(); |
| if (currentContext == null){ |
| currentContext = new Context2(parentContext); |
| } |
| else{ |
| // JJK: This will wipe out any leftover data |
| // if we're reusing a previously allocated Context. |
| currentContext.setParent(parentContext); |
| } |
| } |
| |
| |
| /** |
| * Revert to the previous Namespace context. |
| * |
| * <p>Normally, you should pop the context at the end of each |
| * XML element. After popping the context, all Namespace prefix |
| * mappings that were previously in force are restored.</p> |
| * |
| * <p>You must not attempt to declare additional Namespace |
| * prefixes after popping a context, unless you push another |
| * context first.</p> |
| * |
| * @see #pushContext |
| */ |
| public void popContext () |
| { |
| Context2 parentContext=currentContext.getParent(); |
| if(parentContext==null) |
| throw new EmptyStackException(); |
| else |
| currentContext = parentContext; |
| } |
| |
| |
| |
| //////////////////////////////////////////////////////////////////// |
| // Operations within a context. |
| //////////////////////////////////////////////////////////////////// |
| |
| |
| /** |
| * Declare a Namespace prefix. |
| * |
| * <p>This method declares a prefix in the current Namespace |
| * context; the prefix will remain in force until this context |
| * is popped, unless it is shadowed in a descendant context.</p> |
| * |
| * <p>To declare a default Namespace, use the empty string. The |
| * prefix must not be "xml" or "xmlns".</p> |
| * |
| * <p>Note that you must <em>not</em> declare a prefix after |
| * you've pushed and popped another Namespace.</p> |
| * |
| * <p>Note that there is an asymmetry in this library: while {@link |
| * #getPrefix getPrefix} will not return the default "" prefix, |
| * even if you have declared one; to check for a default prefix, |
| * you have to look it up explicitly using {@link #getURI getURI}. |
| * This asymmetry exists to make it easier to look up prefixes |
| * for attribute names, where the default prefix is not allowed.</p> |
| * |
| * @param prefix The prefix to declare, or null for the empty |
| * string. |
| * @param uri The Namespace URI to associate with the prefix. |
| * @return true if the prefix was legal, false otherwise |
| * @see #processName |
| * @see #getURI |
| * @see #getPrefix |
| */ |
| public boolean declarePrefix (String prefix, String uri) |
| { |
| if (prefix.equals("xml") || prefix.equals("xmlns")) { |
| return false; |
| } else { |
| currentContext.declarePrefix(prefix, uri); |
| return true; |
| } |
| } |
| |
| |
| /** |
| * Process a raw XML 1.0 name. |
| * |
| * <p>This method processes a raw XML 1.0 name in the current |
| * context by removing the prefix and looking it up among the |
| * prefixes currently declared. The return value will be the |
| * array supplied by the caller, filled in as follows:</p> |
| * |
| * <dl> |
| * <dt>parts[0]</dt> |
| * <dd>The Namespace URI, or an empty string if none is |
| * in use.</dd> |
| * <dt>parts[1]</dt> |
| * <dd>The local name (without prefix).</dd> |
| * <dt>parts[2]</dt> |
| * <dd>The original raw name.</dd> |
| * </dl> |
| * |
| * <p>All of the strings in the array will be internalized. If |
| * the raw name has a prefix that has not been declared, then |
| * the return value will be null.</p> |
| * |
| * <p>Note that attribute names are processed differently than |
| * element names: an unprefixed element name will received the |
| * default Namespace (if any), while an unprefixed element name |
| * will not.</p> |
| * |
| * @param qName The raw XML 1.0 name to be processed. |
| * @param parts A string array supplied by the caller, capable of |
| * holding at least three members. |
| * @param isAttribute A flag indicating whether this is an |
| * attribute name (true) or an element name (false). |
| * @return The supplied array holding three internalized strings |
| * representing the Namespace URI (or empty string), the |
| * local name, and the raw XML 1.0 name; or null if there |
| * is an undeclared prefix. |
| * @see #declarePrefix |
| * @see java.lang.String#intern */ |
| public String [] processName (String qName, String[] parts, |
| boolean isAttribute) |
| { |
| String[] name=currentContext.processName(qName, isAttribute); |
| if(name==null) |
| return null; |
| |
| // JJK: This recopying is required because processName may return |
| // a cached result. I Don't Like It. ***** |
| System.arraycopy(name,0,parts,0,3); |
| return parts; |
| } |
| |
| |
| /** |
| * Look up a prefix and get the currently-mapped Namespace URI. |
| * |
| * <p>This method looks up the prefix in the current context. |
| * Use the empty string ("") for the default Namespace.</p> |
| * |
| * @param prefix The prefix to look up. |
| * @return The associated Namespace URI, or null if the prefix |
| * is undeclared in this context. |
| * @see #getPrefix |
| * @see #getPrefixes |
| */ |
| public String getURI (String prefix) |
| { |
| return currentContext.getURI(prefix); |
| } |
| |
| |
| /** |
| * Return an enumeration of all prefixes currently declared. |
| * |
| * <p><strong>Note:</strong> if there is a default prefix, it will not be |
| * returned in this enumeration; check for the default prefix |
| * using the {@link #getURI getURI} with an argument of "".</p> |
| * |
| * @return An enumeration of all prefixes declared in the |
| * current context except for the empty (default) |
| * prefix. |
| * @see #getDeclaredPrefixes |
| * @see #getURI |
| */ |
| public Enumeration getPrefixes () |
| { |
| return currentContext.getPrefixes(); |
| } |
| |
| |
| /** |
| * Return one of the prefixes mapped to a Namespace URI. |
| * |
| * <p>If more than one prefix is currently mapped to the same |
| * URI, this method will make an arbitrary selection; if you |
| * want all of the prefixes, use the {@link #getPrefixes} |
| * method instead.</p> |
| * |
| * <p><strong>Note:</strong> this will never return the empty |
| * (default) prefix; to check for a default prefix, use the {@link |
| * #getURI getURI} method with an argument of "".</p> |
| * |
| * @param uri The Namespace URI. |
| * @return One of the prefixes currently mapped to the URI supplied, |
| * or null if none is mapped or if the URI is assigned to |
| * the default Namespace. |
| * @see #getPrefixes(java.lang.String) |
| * @see #getURI */ |
| public String getPrefix (String uri) |
| { |
| return currentContext.getPrefix(uri); |
| } |
| |
| |
| /** |
| * Return an enumeration of all prefixes currently declared for a URI. |
| * |
| * <p>This method returns prefixes mapped to a specific Namespace |
| * URI. The xml: prefix will be included. If you want only one |
| * prefix that's mapped to the Namespace URI, and you don't care |
| * which one you get, use the {@link #getPrefix getPrefix} |
| * method instead.</p> |
| * |
| * <p><strong>Note:</strong> the empty (default) prefix is |
| * <em>never</em> included in this enumeration; to check for the |
| * presence of a default Namespace, use the {@link #getURI getURI} |
| * method with an argument of "".</p> |
| * |
| * @param uri The Namespace URI. |
| * @return An enumeration of all prefixes declared in the |
| * current context. |
| * @see #getPrefix |
| * @see #getDeclaredPrefixes |
| * @see #getURI */ |
| public Enumeration getPrefixes (String uri) |
| { |
| // JJK: The old code involved creating a vector, filling it |
| // with all the matching prefixes, and then getting its |
| // elements enumerator. Wastes storage, wastes cycles if we |
| // don't actually need them all. Better to either implement |
| // a specific enumerator for these prefixes... or a filter |
| // around the all-prefixes enumerator, which comes out to |
| // roughly the same thing. |
| // |
| // **** Currently a filter. That may not be most efficient |
| // when I'm done restructuring storage! |
| return new PrefixForUriEnumerator(this,uri,getPrefixes()); |
| } |
| |
| |
| /** |
| * Return an enumeration of all prefixes declared in this context. |
| * |
| * <p>The empty (default) prefix will be included in this |
| * enumeration; note that this behaviour differs from that of |
| * {@link #getPrefix} and {@link #getPrefixes}.</p> |
| * |
| * @return An enumeration of all prefixes declared in this |
| * context. |
| * @see #getPrefixes |
| * @see #getURI |
| */ |
| public Enumeration getDeclaredPrefixes () |
| { |
| return currentContext.getDeclaredPrefixes(); |
| } |
| |
| |
| |
| } |
| |
| //////////////////////////////////////////////////////////////////// |
| // Local classes. |
| // These were _internal_ classes... but in fact they don't have to be, |
| // and may be more efficient if they aren't. |
| //////////////////////////////////////////////////////////////////// |
| |
| /** |
| * Implementation of Enumeration filter, wrapped |
| * aroung the get-all-prefixes version of the operation. This is NOT |
| * necessarily the most efficient approach; finding the URI and then asking |
| * what prefixes apply to it might make much more sense. |
| */ |
| class PrefixForUriEnumerator implements Enumeration |
| { |
| private Enumeration allPrefixes; |
| private String uri; |
| private String lookahead=null; |
| private NamespaceSupport2 nsup; |
| |
| // Kluge: Since one can't do a constructor on an |
| // anonymous class (as far as I know)... |
| PrefixForUriEnumerator(NamespaceSupport2 nsup,String uri, Enumeration allPrefixes) |
| { |
| this.nsup=nsup; |
| this.uri=uri; |
| this.allPrefixes=allPrefixes; |
| } |
| |
| public boolean hasMoreElements() |
| { |
| if(lookahead!=null) |
| return true; |
| |
| while(allPrefixes.hasMoreElements()) |
| { |
| String prefix=(String)allPrefixes.nextElement(); |
| if(uri.equals(nsup.getURI(prefix))) |
| { |
| lookahead=prefix; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| public Object nextElement() |
| { |
| if(hasMoreElements()) |
| { |
| String tmp=lookahead; |
| lookahead=null; |
| return tmp; |
| } |
| else |
| throw new java.util.NoSuchElementException(); |
| } |
| } |
| |
| /** |
| * Internal class for a single Namespace context. |
| * |
| * <p>This module caches and reuses Namespace contexts, so the number allocated |
| * will be equal to the element depth of the document, not to the total |
| * number of elements (i.e. 5-10 rather than tens of thousands).</p> |
| */ |
| final class Context2 { |
| |
| //////////////////////////////////////////////////////////////// |
| // Manefest Constants |
| //////////////////////////////////////////////////////////////// |
| |
| /** |
| * An empty enumeration. |
| */ |
| private final static Enumeration EMPTY_ENUMERATION = |
| new Vector().elements(); |
| |
| //////////////////////////////////////////////////////////////// |
| // Protected state. |
| //////////////////////////////////////////////////////////////// |
| |
| Hashtable prefixTable; |
| Hashtable uriTable; |
| Hashtable elementNameTable; |
| Hashtable attributeNameTable; |
| String defaultNS = null; |
| |
| //////////////////////////////////////////////////////////////// |
| // Internal state. |
| //////////////////////////////////////////////////////////////// |
| |
| private Vector declarations = null; |
| private boolean tablesDirty = false; |
| private Context2 parent = null; |
| private Context2 child = null; |
| |
| /** |
| * Create a new Namespace context. |
| */ |
| Context2 (Context2 parent) |
| { |
| if(parent==null) |
| { |
| prefixTable = new Hashtable(); |
| uriTable = new Hashtable(); |
| elementNameTable=null; |
| attributeNameTable=null; |
| } |
| else |
| setParent(parent); |
| } |
| |
| |
| /** |
| * @returns The child Namespace context object, or null if this |
| * is the last currently on the chain. |
| */ |
| Context2 getChild() |
| { |
| return child; |
| } |
| |
| /** |
| * @returns The parent Namespace context object, or null if this |
| * is the root. |
| */ |
| Context2 getParent() |
| { |
| return parent; |
| } |
| |
| /** |
| * (Re)set the parent of this Namespace context. |
| * This is separate from the c'tor because it's re-applied |
| * when a Context2 is reused by push-after-pop. |
| * |
| * @param context The parent Namespace context object. |
| */ |
| void setParent (Context2 parent) |
| { |
| this.parent = parent; |
| parent.child = this; // JJK: Doubly-linked |
| declarations = null; |
| prefixTable = parent.prefixTable; |
| uriTable = parent.uriTable; |
| elementNameTable = parent.elementNameTable; |
| attributeNameTable = parent.attributeNameTable; |
| defaultNS = parent.defaultNS; |
| tablesDirty = false; |
| } |
| |
| |
| /** |
| * Declare a Namespace prefix for this context. |
| * |
| * @param prefix The prefix to declare. |
| * @param uri The associated Namespace URI. |
| * @see org.xml.sax.helpers.NamespaceSupport2#declarePrefix |
| */ |
| void declarePrefix (String prefix, String uri) |
| { |
| // Lazy processing... |
| if (!tablesDirty) { |
| copyTables(); |
| } |
| if (declarations == null) { |
| declarations = new Vector(); |
| } |
| |
| prefix = prefix.intern(); |
| uri = uri.intern(); |
| if ("".equals(prefix)) { |
| if ("".equals(uri)) { |
| defaultNS = null; |
| } else { |
| defaultNS = uri; |
| } |
| } else { |
| prefixTable.put(prefix, uri); |
| uriTable.put(uri, prefix); // may wipe out another prefix |
| } |
| declarations.addElement(prefix); |
| } |
| |
| |
| /** |
| * Process a raw XML 1.0 name in this context. |
| * |
| * @param qName The raw XML 1.0 name. |
| * @param isAttribute true if this is an attribute name. |
| * @return An array of three strings containing the |
| * URI part (or empty string), the local part, |
| * and the raw name, all internalized, or null |
| * if there is an undeclared prefix. |
| * @see org.xml.sax.helpers.NamespaceSupport2#processName |
| */ |
| String [] processName (String qName, boolean isAttribute) |
| { |
| String name[]; |
| Hashtable table; |
| |
| // Select the appropriate table. |
| if (isAttribute) { |
| if(elementNameTable==null) |
| elementNameTable=new Hashtable(); |
| table = elementNameTable; |
| } else { |
| if(attributeNameTable==null) |
| attributeNameTable=new Hashtable(); |
| table = attributeNameTable; |
| } |
| |
| // Start by looking in the cache, and |
| // return immediately if the name |
| // is already known in this content |
| name = (String[])table.get(qName); |
| if (name != null) { |
| return name; |
| } |
| |
| // We haven't seen this name in this |
| // context before. |
| name = new String[3]; |
| int index = qName.indexOf(':'); |
| |
| |
| // No prefix. |
| if (index == -1) { |
| if (isAttribute || defaultNS == null) { |
| name[0] = ""; |
| } else { |
| name[0] = defaultNS; |
| } |
| name[1] = qName.intern(); |
| name[2] = name[1]; |
| } |
| |
| // Prefix |
| else { |
| String prefix = qName.substring(0, index); |
| String local = qName.substring(index+1); |
| String uri; |
| if ("".equals(prefix)) { |
| uri = defaultNS; |
| } else { |
| uri = (String)prefixTable.get(prefix); |
| } |
| if (uri == null) { |
| return null; |
| } |
| name[0] = uri; |
| name[1] = local.intern(); |
| name[2] = qName.intern(); |
| } |
| |
| // Save in the cache for future use. |
| table.put(name[2], name); |
| tablesDirty = true; |
| return name; |
| } |
| |
| |
| /** |
| * Look up the URI associated with a prefix in this context. |
| * |
| * @param prefix The prefix to look up. |
| * @return The associated Namespace URI, or null if none is |
| * declared. |
| * @see org.xml.sax.helpers.NamespaceSupport2#getURI |
| */ |
| String getURI (String prefix) |
| { |
| if ("".equals(prefix)) { |
| return defaultNS; |
| } else if (prefixTable == null) { |
| return null; |
| } else { |
| return (String)prefixTable.get(prefix); |
| } |
| } |
| |
| |
| /** |
| * Look up one of the prefixes associated with a URI in this context. |
| * |
| * <p>Since many prefixes may be mapped to the same URI, |
| * the return value may be unreliable.</p> |
| * |
| * @param uri The URI to look up. |
| * @return The associated prefix, or null if none is declared. |
| * @see org.xml.sax.helpers.NamespaceSupport2#getPrefix |
| */ |
| String getPrefix (String uri) |
| { |
| if (uriTable == null) { |
| return null; |
| } else { |
| return (String)uriTable.get(uri); |
| } |
| } |
| |
| |
| /** |
| * Return an enumeration of prefixes declared in this context. |
| * |
| * @return An enumeration of prefixes (possibly empty). |
| * @see org.xml.sax.helpers.NamespaceSupport2#getDeclaredPrefixes |
| */ |
| Enumeration getDeclaredPrefixes () |
| { |
| if (declarations == null) { |
| return EMPTY_ENUMERATION; |
| } else { |
| return declarations.elements(); |
| } |
| } |
| |
| |
| /** |
| * Return an enumeration of all prefixes currently in force. |
| * |
| * <p>The default prefix, if in force, is <em>not</em> |
| * returned, and will have to be checked for separately.</p> |
| * |
| * @return An enumeration of prefixes (never empty). |
| * @see org.xml.sax.helpers.NamespaceSupport2#getPrefixes |
| */ |
| Enumeration getPrefixes () |
| { |
| if (prefixTable == null) { |
| return EMPTY_ENUMERATION; |
| } else { |
| return prefixTable.keys(); |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////// |
| // Internal methods. |
| //////////////////////////////////////////////////////////////// |
| |
| /** |
| * Copy on write for the internal tables in this context. |
| * |
| * <p>This class is optimized for the normal case where most |
| * elements do not contain Namespace declarations. In that case, |
| * the Context2 will share data structures with its parent. |
| * New tables are obtained only when new declarations are issued, |
| * so they can be popped off the stack.</p> |
| * |
| * <p> JJK: **** Alternative: each Context2 might declare |
| * _only_ its local bindings, and delegate upward if not found.</p> |
| */ |
| private void copyTables () |
| { |
| // Start by copying our parent's bindings |
| prefixTable = (Hashtable)prefixTable.clone(); |
| uriTable = (Hashtable)uriTable.clone(); |
| |
| // Replace the caches with empty ones, rather than |
| // trying to determine which bindings should be flushed. |
| // As far as I can tell, these caches are never actually |
| // used in Xalan... More efficient to remove the whole |
| // cache system? **** |
| if(elementNameTable!=null) |
| elementNameTable=new Hashtable(); |
| if(attributeNameTable!=null) |
| attributeNameTable=new Hashtable(); |
| tablesDirty = true; |
| } |
| |
| } |
| |
| |
| // end of NamespaceSupport2.java |