code: /*
   * 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.
   */
  /*
   * $Id$
   */
  
  package org.apache.xalan.xsltc.compiler;
  
  import java.util.Hashtable;
  import java.util.Stack;
  import java.util.StringTokenizer;
  import java.util.Vector;
  
  import org.apache.xalan.xsltc.compiler.util.MethodType;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  final class SymbolTable {
  
      // These hashtables are used for all stylesheets
      private final Hashtable _stylesheets = new Hashtable();
      private final Hashtable _primops     = new Hashtable();
  
      // These hashtables are used for some stylesheets
      private Hashtable _variables = null;
      private Hashtable _templates = null;
      private Hashtable _attributeSets = null;
      private Hashtable _aliases = null;
      private Hashtable _excludedURI = null;
      private Stack     _excludedURIStack = null;
      private Hashtable _decimalFormats = null;
      private Hashtable _keys = null;
  
      public DecimalFormatting getDecimalFormatting(QName name) {
  	if (_decimalFormats == null) return null;
  	return((DecimalFormatting)_decimalFormats.get(name));
      }
  
      public void addDecimalFormatting(QName name, DecimalFormatting symbols) {
  	if (_decimalFormats == null) _decimalFormats = new Hashtable();
  	_decimalFormats.put(name, symbols);
      }
  
      public Key getKey(QName name) {
  	if (_keys == null) return null;
  	return (Key) _keys.get(name);
      }
  
      public void addKey(QName name, Key key) {
  	if (_keys == null) _keys = new Hashtable();
  	_keys.put(name, key);
      }
      
      public Stylesheet addStylesheet(QName name, Stylesheet node) {
  	return (Stylesheet)_stylesheets.put(name, node);
      }
  	
      public Stylesheet lookupStylesheet(QName name) {
  	return (Stylesheet)_stylesheets.get(name);
      }
  
      public Template addTemplate(Template template) {
  	final QName name = template.getName();
  	if (_templates == null) _templates = new Hashtable();
  	return (Template)_templates.put(name, template);
      }
  	
      public Template lookupTemplate(QName name) {
  	if (_templates == null) return null;
  	return (Template)_templates.get(name);
      }
  
      public Variable addVariable(Variable variable) {
  	if (_variables == null) _variables = new Hashtable();
  	final String name = variable.getName().getStringRep();
  	return (Variable)_variables.put(name, variable);
      }
  	
      public Param addParam(Param parameter) {
  	if (_variables == null) _variables = new Hashtable();
  	final String name = parameter.getName().getStringRep();
  	return (Param)_variables.put(name, parameter);
      }
  	
      public Variable lookupVariable(QName qname) {
  	if (_variables == null) return null;
  	final String name = qname.getStringRep();
  	final Object obj = _variables.get(name);
  	return obj instanceof Variable ? (Variable)obj : null;
      }
  
      public Param lookupParam(QName qname) {
  	if (_variables == null) return null;
  	final String name = qname.getStringRep();
  	final Object obj = _variables.get(name);
  	return obj instanceof Param ? (Param)obj : null;
      }
  	
      public SyntaxTreeNode lookupName(QName qname) {
  	if (_variables == null) return null;
  	final String name = qname.getStringRep();
  	return (SyntaxTreeNode)_variables.get(name);
      }
  
      public AttributeSet addAttributeSet(AttributeSet atts) {
  	if (_attributeSets == null) _attributeSets = new Hashtable();
  	return (AttributeSet)_attributeSets.put(atts.getName(), atts);
      }
  
      public AttributeSet lookupAttributeSet(QName name) {
  	if (_attributeSets == null) return null;
  	return (AttributeSet)_attributeSets.get(name);
      }
  
      /**
       * Add a primitive operator or function to the symbol table. To avoid
       * name clashes with user-defined names, the prefix <tt>PrimopPrefix</tt>
       * is prepended.
       */
      public void addPrimop(String name, MethodType mtype) {
  	Vector methods = (Vector)_primops.get(name);
  	if (methods == null) {
  	    _primops.put(name, methods = new Vector());
  	}
  	methods.addElement(mtype);
      }
  	
      /**
       * Lookup a primitive operator or function in the symbol table by
       * prepending the prefix <tt>PrimopPrefix</tt>.
       */
      public Vector lookupPrimop(String name) {
  	return (Vector)_primops.get(name);
      }
  
      /**
       * This is used for xsl:attribute elements that have a "namespace"
       * attribute that is currently not defined using xmlns:
       */
      private int _nsCounter = 0;
  
      public String generateNamespacePrefix() {
  	return("ns"+(_nsCounter++));
      }
  
      /**
       * Use a namespace prefix to lookup a namespace URI
       */
      private SyntaxTreeNode _current = null;
  
      public void setCurrentNode(SyntaxTreeNode node) {
  	_current = node;
      }
  
      public String lookupNamespace(String prefix) {
  	if (_current == null) return(Constants.EMPTYSTRING);
  	return(_current.lookupNamespace(prefix));
      }
  
      /**
       * Adds an alias for a namespace prefix
       */ 
      public void addPrefixAlias(String prefix, String alias) {
  	if (_aliases == null) _aliases = new Hashtable();
  	_aliases.put(prefix,alias);
      }
  
      /**
       * Retrieves any alias for a given namespace prefix
       */ 
      public String lookupPrefixAlias(String prefix) {
  	if (_aliases == null) return null;
  	return (String)_aliases.get(prefix);
      }
  
      /**
       * Register a namespace URI so that it will not be declared in the output
       * unless it is actually referenced in the output.
       */
      public void excludeURI(String uri) {
  	// The null-namespace cannot be excluded
  	if (uri == null) return;
  
  	// Create new hashtable of exlcuded URIs if none exists
  	if (_excludedURI == null) _excludedURI = new Hashtable();
  
  	// Register the namespace URI
  	Integer refcnt = (Integer)_excludedURI.get(uri);
  	if (refcnt == null)
  	    refcnt = new Integer(1);
  	else
  	    refcnt = new Integer(refcnt.intValue() + 1);
  	_excludedURI.put(uri,refcnt);
      }
  
      /**
       * Exclude a series of namespaces given by a list of whitespace
       * separated namespace prefixes.
       */
      public void excludeNamespaces(String prefixes) {
  	if (prefixes != null) {
  	    StringTokenizer tokens = new StringTokenizer(prefixes);
  	    while (tokens.hasMoreTokens()) {
  		final String prefix = tokens.nextToken();
  		final String uri;
  		if (prefix.equals("#default"))
  		    uri = lookupNamespace(Constants.EMPTYSTRING);
  		else
  		    uri = lookupNamespace(prefix);
  		if (uri != null) excludeURI(uri);
  	    }
  	}
      }
  
      /**
       * Check if a namespace should not be declared in the output (unless used)
       */
      public boolean isExcludedNamespace(String uri) {
  	if (uri != null && _excludedURI != null) {
  	    final Integer refcnt = (Integer)_excludedURI.get(uri);
  	    return (refcnt != null && refcnt.intValue() > 0);
  	}
  	return false;
      }
  
      /**
       * Turn of namespace declaration exclusion
       */
      public void unExcludeNamespaces(String prefixes) {
  	if (_excludedURI == null) return;
  	if (prefixes != null) {
  	    StringTokenizer tokens = new StringTokenizer(prefixes);
  	    while (tokens.hasMoreTokens()) {
  		final String prefix = tokens.nextToken();
  		final String uri;
  		if (prefix.equals("#default"))
  		    uri = lookupNamespace(Constants.EMPTYSTRING);
  		else
  		    uri = lookupNamespace(prefix);
  		Integer refcnt = (Integer)_excludedURI.get(uri);
  		if (refcnt != null)
  		    _excludedURI.put(uri, new Integer(refcnt.intValue() - 1));
  	    }
  	}	
      }
  
      /**
       * Exclusion of namespaces by a stylesheet does not extend to any stylesheet
       * imported or included by the stylesheet.  Upon entering the context of a
       * new stylesheet, a call to this method is needed to clear the current set
       * of excluded namespaces temporarily.  Every call to this method requires
       * a corresponding call to {@link #popExcludedNamespacesContext()}.
       */
      public void pushExcludedNamespacesContext() {
          if (_excludedURIStack == null) {
              _excludedURIStack = new Stack();
          }
          _excludedURIStack.push(_excludedURI);
          _excludedURI = null;
      }
      
      /**
       * Exclusion of namespaces by a stylesheet does not extend to any stylesheet
       * imported or included by the stylesheet.  Upon exiting the context of a
       * stylesheet, a call to this method is needed to restore the set of
       * excluded namespaces that was in effect prior to entering the context of
       * the current stylesheet.
       */
      public void popExcludedNamespacesContext() {
          _excludedURI = (Hashtable) _excludedURIStack.pop();
          if (_excludedURIStack.isEmpty()) {
              _excludedURIStack = null;
          }
      }
  
  }
  
  