/*
 * 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.xerces.xinclude;

import java.util.Enumeration;

import org.apache.xerces.util.NamespaceSupport;
import org.apache.xerces.util.XMLSymbols;
import org.apache.xerces.xni.NamespaceContext;

This implementation of NamespaceContext has the ability to maintain multiple
scopes of namespace/prefix bindings.  This is useful in situations when it is
not always appropriate for elements to inherit the namespace bindings of their
ancestors (such as included elements in XInclude).
When searching for a URI to match a prefix, or a prefix to match a URI, it is
searched for in the current context, then the ancestors of the current context,
up to the beginning of the current scope.  Other scopes are not searched.
Author:
Peter McCracken, IBM
Version:
$Id: MultipleScopeNamespaceSupport.java 447243 2006-09-18 05:15:27Z mrglavas $/**
 * This implementation of NamespaceContext has the ability to maintain multiple
 * scopes of namespace/prefix bindings.  This is useful in situations when it is
 * not always appropriate for elements to inherit the namespace bindings of their
 * ancestors (such as included elements in XInclude).
 * 
 * When searching for a URI to match a prefix, or a prefix to match a URI, it is
 * searched for in the current context, then the ancestors of the current context,
 * up to the beginning of the current scope.  Other scopes are not searched.
 * 
 * @author Peter McCracken, IBM
 * 
 * @version $Id: MultipleScopeNamespaceSupport.java 447243 2006-09-18 05:15:27Z mrglavas $
 */
public class MultipleScopeNamespaceSupport extends NamespaceSupport {

    protected int[] fScope = new int[8];
    protected int fCurrentScope;

    /**
     * 
     */
    public MultipleScopeNamespaceSupport() {
        super();
        fCurrentScope = 0;
        fScope[0] = 0;
    }

    
Params:
context – /**
     * @param context
     */
    public MultipleScopeNamespaceSupport(NamespaceContext context) {
        super(context);
        fCurrentScope = 0;
        fScope[0] = 0;
    }

    /* (non-Javadoc)
     * @see org.apache.xerces.xni.NamespaceContext#getAllPrefixes()
     */
    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 = fContext[fScope[fCurrentScope]];
            i <= (fNamespaceSize - 2);
            i += 2) {
            prefix = fNamespace[i];
            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);
    }

    public int getScopeForContext(int context) {
        int scope = fCurrentScope;
        while (context < fScope[scope]) {
            scope--;
        }
        return scope;
    }

    /* (non-Javadoc)
     * @see org.apache.xerces.xni.NamespaceContext#getPrefix(java.lang.String)
     */
    public String getPrefix(String uri) {
        return getPrefix(uri, fNamespaceSize, fContext[fScope[fCurrentScope]]);
    }

    /* (non-Javadoc)
     * @see org.apache.xerces.xni.NamespaceContext#getURI(java.lang.String)
     */
    public String getURI(String prefix) {
        return getURI(prefix, fNamespaceSize, fContext[fScope[fCurrentScope]]);
    }

    public String getPrefix(String uri, int context) {
        return getPrefix(uri, fContext[context+1], fContext[fScope[getScopeForContext(context)]]);
    }

    public String getURI(String prefix, int context) {
        return getURI(prefix, fContext[context+1], fContext[fScope[getScopeForContext(context)]]);
    }

    public String getPrefix(String uri, int start, int end) {
        // this saves us from having a copy of each of these in fNamespace for each scope
        if (uri == NamespaceContext.XML_URI) {
            return XMLSymbols.PREFIX_XML;
        }
        if (uri == NamespaceContext.XMLNS_URI) {
            return XMLSymbols.PREFIX_XMLNS;
        }

        // find uri in current context
        for (int i = start; i > end; i -= 2) {
            if (fNamespace[i - 1] == uri) {
                if (getURI(fNamespace[i - 2]) == uri)
                    return fNamespace[i - 2];
            }
        }

        // uri not found
        return null;
    }

    public String getURI(String prefix, int start, int end) {
        // this saves us from having a copy of each of these in fNamespace for each scope
        if (prefix == XMLSymbols.PREFIX_XML) {
            return NamespaceContext.XML_URI;
        }
        if (prefix == XMLSymbols.PREFIX_XMLNS) {
            return NamespaceContext.XMLNS_URI;
        }

        // find prefix in current context
        for (int i = start; i > end; i -= 2) {
            if (fNamespace[i - 2] == prefix) {
                return fNamespace[i - 1];
            }
        }

        // prefix not found
        return null;
    }

    
Only resets the current scope -- all namespaces defined in lower scopes
remain valid after a call to reset.
/**
     * Only resets the current scope -- all namespaces defined in lower scopes
     * remain valid after a call to reset.
     */
    public void reset() {
        fCurrentContext = fScope[fCurrentScope];
        fNamespaceSize = fContext[fCurrentContext];
    }

    
Begins a new scope.  None of the previous namespace bindings will be used,
until the new scope is popped with popScope()
/**
     * Begins a new scope.  None of the previous namespace bindings will be used,
     * until the new scope is popped with popScope()
     */
    public void pushScope() {
        if (fCurrentScope + 1 == fScope.length) {
            int[] contextarray = new int[fScope.length * 2];
            System.arraycopy(fScope, 0, contextarray, 0, fScope.length);
            fScope = contextarray;
        }
        pushContext();
        fScope[++fCurrentScope] = fCurrentContext;
    }

    
Pops the current scope.  The namespace bindings from the new current scope
are then used for searching for namespaces and prefixes.
/**
     * Pops the current scope.  The namespace bindings from the new current scope
     * are then used for searching for namespaces and prefixes.
     */
    public void popScope() {
        fCurrentContext = fScope[fCurrentScope--];
        popContext();
    }
}