content: /*
   * 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 mf.org.apache.xerces.util;
  
  import java.util.Enumeration;
  import java.util.NoSuchElementException;
  
  import mf.org.apache.xerces.xni.NamespaceContext;
  
  /**
   * Namespace support for XML document handlers. This class doesn't
   * perform any error checking and assumes that all strings passed
   * as arguments to methods are unique symbols. The SymbolTable class
   * can be used for this purpose.
   *
   * @author Andy Clark, IBM
   * @version $Id: NamespaceSupport.java 965250 2010-07-18 16:04:58Z mrglavas $
   */
  public class NamespaceSupport implements NamespaceContext {
  
      //
      // Data
      //
  
      /**
       * Namespace binding information. This array is composed of a
       * series of tuples containing the namespace binding information:
       * &lt;prefix, uri&gt;. The default size can be set to anything
       * as long as it is a power of 2 greater than 1.
       *
       * @see #fNamespaceSize
       * @see #fContext
       */
      protected String[] fNamespace = new String[16 * 2];
  
      /**
       * The top of the namespace information array.
       */
      protected int fNamespaceSize;
  
      // NOTE: The constructor depends on the initial context size 
      //       being at least 1. -Ac
  
      /**
       * Context indexes. This array contains indexes into the namespace
       * information array. The index at the current context is the start
       * index of declared namespace bindings and runs to the size of the
       * namespace information array.
       *
       * @see #fNamespaceSize
       */
      protected int[] fContext = new int[8];
  
      /**
       * The current context.
       */
      protected int fCurrentContext;
  
      protected String[] fPrefixes = new String[16];
  
      //
      // Constructors
      //
  
      /**
       * Default constructor.
       */
      public NamespaceSupport() {
      } // <init>()
  
      /**
       * Constructs a namespace context object and initializes it with
       * the prefixes declared in the specified context.
       */
      public NamespaceSupport(NamespaceContext context) {
          pushContext();
          // copy declaration in the context
          Enumeration prefixes = context.getAllPrefixes();
          while (prefixes.hasMoreElements()) {
              String prefix = (String) prefixes.nextElement();
              String uri = context.getURI(prefix);
              declarePrefix(prefix, uri);
          }
      } // <init>(NamespaceContext)
  
  
      //
      // Public methods
      //
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#reset()
       */
      @Override
      public void reset() {
  
          // reset namespace and context info
          fNamespaceSize = 0;
          fCurrentContext = 0;
          fContext[fCurrentContext] = fNamespaceSize;
  
          // bind "xml" prefix to the XML uri
          fNamespace[fNamespaceSize++] = XMLSymbols.PREFIX_XML;
          fNamespace[fNamespaceSize++] = NamespaceContext.XML_URI;
          // bind "xmlns" prefix to the XMLNS uri
          fNamespace[fNamespaceSize++] = XMLSymbols.PREFIX_XMLNS;
          fNamespace[fNamespaceSize++] = NamespaceContext.XMLNS_URI;
          ++fCurrentContext;
  
      } // reset(SymbolTable)
  
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#pushContext()
       */
      @Override
      public void pushContext() {
  
          // extend the array, if necessary
          if (fCurrentContext + 1 == fContext.length) {
              int[] contextarray = new int[fContext.length * 2];
              System.arraycopy(fContext, 0, contextarray, 0, fContext.length);
              fContext = contextarray;
          }
  
          // push context
          fContext[++fCurrentContext] = fNamespaceSize;
  
      } // pushContext()
  
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#popContext()
       */
      @Override
      public void popContext() {
          fNamespaceSize = fContext[fCurrentContext--];
      } // popContext()
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#declarePrefix(String, String)
       */
      @Override
      public boolean declarePrefix(String prefix, String uri) {
          // ignore "xml" and "xmlns" prefixes
          if (prefix == XMLSymbols.PREFIX_XML || prefix == XMLSymbols.PREFIX_XMLNS) {
              return false;
          }
  
          // see if prefix already exists in current context
          for (int i = fNamespaceSize; i > fContext[fCurrentContext]; i -= 2) {
              if (fNamespace[i - 2] == prefix) {
                  // REVISIT: [Q] Should the new binding override the
                  //          previously declared binding or should it
                  //          it be ignored? -Ac
                  // NOTE:    The SAX2 "NamespaceSupport" helper allows
                  //          re-bindings with the new binding overwriting
                  //          the previous binding. -Ac
                  fNamespace[i - 1] = uri;
                  return true;
              }
          }
  
          // resize array, if needed
          if (fNamespaceSize == fNamespace.length) {
              String[] namespacearray = new String[fNamespaceSize * 2];
              System.arraycopy(fNamespace, 0, namespacearray, 0, fNamespaceSize);
              fNamespace = namespacearray;
          }
  
          // bind prefix to uri in current context
          fNamespace[fNamespaceSize++] = prefix;
          fNamespace[fNamespaceSize++] = uri;
  
          return true;
  
      } // declarePrefix(String,String):boolean
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#getURI(String)
       */
      @Override
      public String getURI(String prefix) {
  
          // find prefix in current context
          for (int i = fNamespaceSize; i > 0; i -= 2) {
              if (fNamespace[i - 2] == prefix) {
                  return fNamespace[i - 1];
              }
          }
  
          // prefix not found
          return null;
  
      } // getURI(String):String
  
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#getPrefix(String)
       */
      @Override
      public String getPrefix(String uri) {
  
          // find uri in current context
          for (int i = fNamespaceSize; i > 0; i -= 2) {
              if (fNamespace[i - 1] == uri) {
                  if (getURI(fNamespace[i - 2]) == uri)
                      return fNamespace[i - 2];
              }
          }
  
          // uri not found
          return null;
  
      } // getPrefix(String):String
  
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#getDeclaredPrefixCount()
       */
      @Override
      public int getDeclaredPrefixCount() {
          return (fNamespaceSize - fContext[fCurrentContext]) / 2;
      } // getDeclaredPrefixCount():int
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#getDeclaredPrefixAt(int)
       */
      @Override
      public String getDeclaredPrefixAt(int index) {
          return fNamespace[fContext[fCurrentContext] + index * 2];
      } // getDeclaredPrefixAt(int):String
  
      /**
       * @see mf.org.apache.xerces.xni.NamespaceContext#getAllPrefixes()
       */
      @Override
      public Enumeration getAllPrefixes() {
          int count = 0;
          if (fPrefixes.length < (fNamespace.length / 2)) {
              // resize prefix array          
              String[] prefixes = new String[fNamespaceSize];
              fPrefixes = prefixes;
          }
          String prefix = null;
          boolean unique = true;
          for (int i = 2; i < (fNamespaceSize - 2); i += 2) {
              prefix = fNamespace[i + 2];
              for (int k = 0; k < count; k++) {
                  if (fPrefixes[k] == prefix) {
                      unique = false;
                      break;
                  }
              }
              if (unique) {
                  fPrefixes[count++] = prefix;
              }
              unique = true;
          }
          return new Prefixes(fPrefixes, count);
      }
      
      /*
       * non-NamespaceContext methods
       */
  
      /**
       * Checks whether a binding or unbinding for
       * the given prefix exists in the context.
       *
       * @param prefix The prefix to look up.
       * @return true if the given prefix exists in the context
       */
      public boolean containsPrefix(String prefix) {
  
          // find prefix in current context
          for (int i = fNamespaceSize; i > 0; i -= 2) {
              if (fNamespace[i - 2] == prefix) {
                  return true;
              }
          }
  
          // prefix not found
          return false;
      }
  
      protected final class Prefixes implements Enumeration {
          private String[] prefixes;
          private int counter = 0;
          private int size = 0;
  
          /**
           * Constructor for Prefixes.
           */
          public Prefixes(String[] prefixes, int size) {
              this.prefixes = prefixes;
              this.size = size;
          }
  
          /**
           * @see java.util.Enumeration#hasMoreElements()
           */
          @Override
          public boolean hasMoreElements() {
              return (counter < size);
          }
  
          /**
           * @see java.util.Enumeration#nextElement()
           */
          @Override
          public Object nextElement() {
              if (counter < size) {
                  return fPrefixes[counter++];
              }
              throw new NoSuchElementException("Illegal access to Namespace prefixes enumeration.");
          }
  
          @Override
          public String toString() {
              StringBuffer buf = new StringBuffer();
              for (int i = 0; i < size; i++) {
                  buf.append(prefixes[i]);
                  buf.append(' ');
              }
  
              return buf.toString();
          }
  
      }
  
  } // class NamespaceSupport
  