/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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 com.sun.org.apache.xpath.internal.functions;

import com.sun.org.apache.xalan.internal.templates.Constants;

import com.sun.org.apache.xpath.internal.ExtensionsProvider;

import com.sun.org.apache.xpath.internal.XPathContext;

import com.sun.org.apache.xpath.internal.compiler.FunctionTable;

import com.sun.org.apache.xpath.internal.objects.XBoolean;

import com.sun.org.apache.xpath.internal.objects.XObject;

/**

 * Execute the ExtFunctionAvailable() function.

 * @xsl.usage advanced

 */

public class FuncExtFunctionAvailable extends FunctionOneArg

{

    static final long serialVersionUID = 5118814314918592241L;

    transient private FunctionTable m_functionTable = null;

  /**

   * Execute the function.  The function must return

   * a valid object.

   * @param xctxt The current execution context.

   * @return A valid XObject.

   *

   * @throws javax.xml.transform.TransformerException

   */

  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException

  {

    String prefix;

    String namespace;

    String methName;

    String fullName = m_arg0.execute(xctxt).str();

    int indexOfNSSep = fullName.indexOf(':');

    if (indexOfNSSep < 0)

    {

      prefix = "";

      namespace = Constants.S_XSLNAMESPACEURL;

      methName = fullName;

    }

    else

    {

      prefix = fullName.substring(0, indexOfNSSep);

      namespace = xctxt.getNamespaceContext().getNamespaceForPrefix(prefix);

      if (null == namespace)

        return XBoolean.S_FALSE;

        methName = fullName.substring(indexOfNSSep + 1);

    }

    if (namespace.equals(Constants.S_XSLNAMESPACEURL))

    {

      try

      {

        if (null == m_functionTable) m_functionTable = new FunctionTable();

        return m_functionTable.functionAvailable(methName) ? XBoolean.S_TRUE : XBoolean.S_FALSE;

      }

      catch (Exception e)

      {

        return XBoolean.S_FALSE;

      }

    }

    else

    {

      //dml

      ExtensionsProvider extProvider = (ExtensionsProvider)xctxt.getOwnerObject();

      return extProvider.functionAvailable(namespace, methName)

             ? XBoolean.S_TRUE : XBoolean.S_FALSE;

    }

  }

  /**

   * The function table is an instance field. In order to access this instance

   * field during evaluation, this method is called at compilation time to

   * insert function table information for later usage. It should only be used

   * during compiling of XPath expressions.

   * @param aTable an instance of the function table

   */

  public void setFunctionTable(FunctionTable aTable){

          m_functionTable = aTable;

  }

}