/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2004 The Apache Software Foundation.

 *

 * Licensed 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: DTMManager.java,v 1.2.4.1 2005/09/15 08:14:54 suresh_emailid Exp $

 */

package com.sun.org.apache.xml.internal.dtm;

import com.sun.org.apache.xml.internal.res.XMLErrorResources;

import com.sun.org.apache.xml.internal.res.XMLMessages;

import com.sun.org.apache.xml.internal.utils.PrefixResolver;

import com.sun.org.apache.xml.internal.utils.XMLStringFactory;

import com.sun.org.apache.xalan.internal.utils.ObjectFactory;

/**

 * A DTMManager instance can be used to create DTM and

 * DTMIterator objects, and manage the DTM objects in the system.

 *

 * <p>The system property that determines which Factory implementation

 * to create is named "com.sun.org.apache.xml.internal.utils.DTMFactory". This

 * property names a concrete subclass of the DTMFactory abstract

 *  class. If the property is not defined, a platform default is be used.</p>

 *

 * <p>An instance of this class <emph>must</emph> be safe to use across

 * thread instances.  It is expected that a client will create a single instance

 * of a DTMManager to use across multiple threads.  This will allow sharing

 * of DTMs across multiple processes.</p>

 *

 * <p>Note: this class is incomplete right now.  It will be pretty much

 * modeled after javax.xml.transform.TransformerFactory in terms of its

 * factory support.</p>

 *

 * <p>State: In progress!!</p>

 */

public abstract class DTMManager

{

  /** The default property name to load the manager. */

  private static final String defaultPropName =

    "com.sun.org.apache.xml.internal.dtm.DTMManager";

  /** The default class name to use as the manager. */

  private static String defaultClassName =

    "com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault";

  /**

   * Factory for creating XMLString objects.

   *  %TBD% Make this set by the caller.

   */

  protected XMLStringFactory m_xsf = null;

  private boolean _useServicesMechanism;

  /**

   * Default constructor is protected on purpose.

   */

  protected DTMManager(){}

  /**

   * Get the XMLStringFactory used for the DTMs.

   *

   *

   * @return a valid XMLStringFactory object, or null if it hasn't been set yet.

   */

  public XMLStringFactory getXMLStringFactory()

  {

    return m_xsf;

  }

  /**

   * Set the XMLStringFactory used for the DTMs.

   *

   *

   * @param xsf a valid XMLStringFactory object, should not be null.

   */

  public void setXMLStringFactory(XMLStringFactory xsf)

  {

    m_xsf = xsf;

  }

  /**

   * Obtain a new instance of a <code>DTMManager</code>.

   * This static method creates a new factory instance

   * This method uses the following ordered lookup procedure to determine

   * the <code>DTMManager</code> implementation class to

   * load:

   * <ul>

   * <li>

   * Use the <code>com.sun.org.apache.xml.internal.dtm.DTMManager</code> system

   * property.

   * </li>

   * <li>

   * Use the JAVA_HOME(the parent directory where jdk is

   * installed)/lib/xalan.properties for a property file that contains the

   * name of the implementation class keyed on the same value as the

   * system property defined above.

   * </li>

   * <li>

   * Use the Services API (as detailed in the JAR specification), if

   * available, to determine the classname. The Services API will look

   * for a classname in the file

   * <code>META-INF/services/com.sun.org.apache.xml.internal.dtm.DTMManager</code>

   * in jars available to the runtime.

   * </li>

   * <li>

   * Use the default <code>DTMManager</code> classname, which is

   * <code>com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault</code>.

   * </li>

   * </ul>

   *

   * Once an application has obtained a reference to a <code>

   * DTMManager</code> it can use the factory to configure

   * and obtain parser instances.

   *

   * @return new DTMManager instance, never null.

   *

   * @throws DTMConfigurationException

   * if the implementation is not available or cannot be instantiated.

   */

  public static DTMManager newInstance(XMLStringFactory xsf)

           throws DTMConfigurationException

  {

    return newInstance(xsf, true);

  }

  public static DTMManager newInstance(XMLStringFactory xsf, boolean useServicesMechanism)

           throws DTMConfigurationException

  {

    DTMManager factoryImpl = null;

    try

    {

        if (useServicesMechanism) {

            factoryImpl = (DTMManager) ObjectFactory

                .createObject(defaultPropName, defaultClassName);

        } else {

            factoryImpl = new com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault();

        }

    }

    catch (ConfigurationError e)

    {

      throw new DTMConfigurationException(XMLMessages.createXMLMessage(

        XMLErrorResources.ER_NO_DEFAULT_IMPL, null), e.getException());

        //"No default implementation found");

    }

    if (factoryImpl == null)

    {

      throw new DTMConfigurationException(XMLMessages.createXMLMessage(

        XMLErrorResources.ER_NO_DEFAULT_IMPL, null));

        //"No default implementation found");

    }

    factoryImpl.setXMLStringFactory(xsf);

    return factoryImpl;

  }

  /**

   * Get an instance of a DTM, loaded with the content from the

   * specified source.  If the unique flag is true, a new instance will

   * always be returned.  Otherwise it is up to the DTMManager to return a

   * new instance or an instance that it already created and may be being used

   * by someone else.

   *

   * (More parameters may eventually need to be added for error handling

   * and entity resolution, and to better control selection of implementations.)

   *

   * @param source the specification of the source object, which may be null,

   *               in which case it is assumed that node construction will take

   *               by some other means.

   * @param unique true if the returned DTM must be unique, probably because it

   * is going to be mutated.

   * @param whiteSpaceFilter Enables filtering of whitespace nodes, and may

   *                         be null.

   * @param incremental true if the DTM should be built incrementally, if

   *                    possible.

   * @param doIndexing true if the caller considers it worth it to use

   *                   indexing schemes.

   *

   * @return a non-null DTM reference.

   */

  public abstract DTM getDTM(javax.xml.transform.Source source,

                             boolean unique, DTMWSFilter whiteSpaceFilter,

                             boolean incremental, boolean doIndexing);

  /**

   * Get the instance of DTM that "owns" a node handle.

   *

   * @param nodeHandle the nodeHandle.

   *

   * @return a non-null DTM reference.

   */

  public abstract DTM getDTM(int nodeHandle);

  /**

   * Given a W3C DOM node, try and return a DTM handle.

   * Note: calling this may be non-optimal.

   *

   * @param node Non-null reference to a DOM node.

   *

   * @return a valid DTM handle.

   */

  public abstract int getDTMHandleFromNode(org.w3c.dom.Node node);

  /**

   * Creates a DTM representing an empty <code>DocumentFragment</code> object.

   * @return a non-null DTM reference.

   */

  public abstract DTM createDocumentFragment();

  /**

   * Release a DTM either to a lru pool, or completely remove reference.

   * DTMs without system IDs are always hard deleted.

   * State: experimental.

   *

   * @param dtm The DTM to be released.

   * @param shouldHardDelete True if the DTM should be removed no matter what.

   * @return true if the DTM was removed, false if it was put back in a lru pool.

   */

  public abstract boolean release(DTM dtm, boolean shouldHardDelete);

  /**

   * Create a new <code>DTMIterator</code> based on an XPath

   * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or

   * a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.

   *

   * @param xpathCompiler ??? Somehow we need to pass in a subpart of the

   * expression.  I hate to do this with strings, since the larger expression

   * has already been parsed.

   *

   * @param pos The position in the expression.

   * @return The newly created <code>DTMIterator</code>.

   */

  public abstract DTMIterator createDTMIterator(Object xpathCompiler,

          int pos);

  /**

   * Create a new <code>DTMIterator</code> based on an XPath

   * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or

   * a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.

   *

   * @param xpathString Must be a valid string expressing a

   * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or

   * a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.

   *

   * @param presolver An object that can resolve prefixes to namespace URLs.

   *

   * @return The newly created <code>DTMIterator</code>.

   */

  public abstract DTMIterator createDTMIterator(String xpathString,

          PrefixResolver presolver);

  /**

   * Create a new <code>DTMIterator</code> based only on a whatToShow

   * and a DTMFilter.  The traversal semantics are defined as the

   * descendant access.

   * <p>

   * Note that DTMIterators may not be an exact match to DOM

   * NodeIterators. They are initialized and used in much the same way

   * as a NodeIterator, but their response to document mutation is not

   * currently defined.

   *

   * @param whatToShow This flag specifies which node types may appear in

   *   the logical view of the tree presented by the iterator. See the

   *   description of <code>NodeFilter</code> for the set of possible

   *   <code>SHOW_</code> values.These flags can be combined using

   *   <code>OR</code>.

   * @param filter The <code>NodeFilter</code> to be used with this

   *   <code>DTMFilter</code>, or <code>null</code> to indicate no filter.

   * @param entityReferenceExpansion The value of this flag determines

   *   whether entity reference nodes are expanded.

   *

   * @return The newly created <code>DTMIterator</code>.

   */

  public abstract DTMIterator createDTMIterator(int whatToShow,

          DTMFilter filter, boolean entityReferenceExpansion);

  /**

   * Create a new <code>DTMIterator</code> that holds exactly one node.

   *

   * @param node The node handle that the DTMIterator will iterate to.

   *

   * @return The newly created <code>DTMIterator</code>.

   */

  public abstract DTMIterator createDTMIterator(int node);

  /* Flag indicating whether an incremental transform is desired */

  public boolean m_incremental = false;

  /*

   * Flag set by FEATURE_SOURCE_LOCATION.

   * This feature specifies whether the transformation phase should

   * keep track of line and column numbers for the input source

   * document.

   */

  public boolean m_source_location = false;

  /**

   * Get a flag indicating whether an incremental transform is desired

   * @return incremental boolean.

   *

   */

  public boolean getIncremental()

  {

    return m_incremental;

  }

  /**

   * Set a flag indicating whether an incremental transform is desired

   * This flag should have the same value as the FEATURE_INCREMENTAL feature

   * which is set by the TransformerFactory.setAttribut() method before a

   * DTMManager is created

   * @param incremental boolean to use to set m_incremental.

   *

   */

  public void setIncremental(boolean incremental)

  {

    m_incremental = incremental;

  }

  /**

   * Get a flag indicating whether the transformation phase should

   * keep track of line and column numbers for the input source

   * document.

   * @return source location boolean

   *

   */

  public boolean getSource_location()

  {

    return m_source_location;

  }

  /**

   * Set a flag indicating whether the transformation phase should

   * keep track of line and column numbers for the input source

   * document.

   * This flag should have the same value as the FEATURE_SOURCE_LOCATION feature

   * which is set by the TransformerFactory.setAttribut() method before a

   * DTMManager is created

   * @param sourceLocation boolean to use to set m_source_location

   */

  public void setSource_location(boolean sourceLocation){

    m_source_location = sourceLocation;

  }

    /**

     * Return the state of the services mechanism feature.

     */

    public boolean useServicesMechnism() {

        return _useServicesMechanism;

    }

    /**

     * Set the state of the services mechanism feature.

     */

    public void setServicesMechnism(boolean flag) {

        _useServicesMechanism = flag;

    }

  // -------------------- private methods --------------------

   /**

   * Temp debug code - this will be removed after we test everything

   */

  private static boolean debug;

  static

  {

    try

    {

    }

    catch (SecurityException ex){}

  }

  /** This value, set at compile time, controls how many bits of the

   * DTM node identifier numbers are used to identify a node within a

   * document, and thus sets the maximum number of nodes per

   * document. The remaining bits are used to identify the DTM

   * document which contains this node.

   *

   * If you change IDENT_DTM_NODE_BITS, be sure to rebuild _ALL_ the

   * files which use it... including the IDKey testcases.

   *

   * (FuncGenerateKey currently uses the node identifier directly and

   * thus is affected when this changes. The IDKEY results will still be

   * _correct_ (presuming no other breakage), but simple equality

   * comparison against the previous "golden" files will probably

   * complain.)

   * */

  public static final int IDENT_DTM_NODE_BITS = 16;

  /** When this bitmask is ANDed with a DTM node handle number, the result

   * is the low bits of the node's index number within that DTM. To obtain

   * the high bits, add the DTM ID portion's offset as assigned in the DTM

   * Manager.

   */

  public static final int IDENT_NODE_DEFAULT = (1<<IDENT_DTM_NODE_BITS)-1;

  /** When this bitmask is ANDed with a DTM node handle number, the result

   * is the DTM's document identity number.

   */

  public static final int IDENT_DTM_DEFAULT = ~IDENT_NODE_DEFAULT;

  /** This is the maximum number of DTMs available.  The highest DTM is

    * one less than this.

   */

  public static final int IDENT_MAX_DTMS = (IDENT_DTM_DEFAULT >>> IDENT_DTM_NODE_BITS) + 1;

  /**

   * %TBD% Doc

   *

   * NEEDSDOC @param dtm

   *

   * NEEDSDOC ($objectName$) @return

   */

  public abstract int getDTMIdentity(DTM dtm);

  /**

   * %TBD% Doc

   *

   * NEEDSDOC ($objectName$) @return

   */

  public int getDTMIdentityMask()

  {

    return IDENT_DTM_DEFAULT;

  }

  /**

   * %TBD% Doc

   *

   * NEEDSDOC ($objectName$) @return

   */

  public int getNodeIdentityMask()

  {

    return IDENT_NODE_DEFAULT;

  }

    //

    // Classes

    //

    /**

     * A configuration error.

     * Originally in ObjectFactory. This is the only portion used in this package

     */

    static class ConfigurationError

        extends Error {

                static final long serialVersionUID = 5122054096615067992L;

        //

        // Data

        //

        /** Exception. */

        private Exception exception;

        //

        // Constructors

        //

        /**

         * Construct a new instance with the specified detail string and

         * exception.

         */

        ConfigurationError(String msg, Exception x) {

            super(msg);

            this.exception = x;

        } // <init>(String,Exception)

        //

        // Public methods

        //

        /** Returns the exception associated to this error. */

        Exception getException() {

            return exception;

        } // getException():Exception

    } // class ConfigurationError

}