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Java example source code file (Helper.java)

This example Java source code file (Helper.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

auxgen, helper, interfaceentry, interfacestate, local, primitiveentry, string, stub, symtabentry, tcoffsets, typedefentry, util, valueboxentry, valueentry

The Helper.java Java example source code

/*
 * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
/*
 * COMPONENT_NAME: idl.toJava
 *
 * ORIGINS: 27
 *
 * Licensed Materials - Property of IBM
 * 5639-D57 (C) COPYRIGHT International Business Machines Corp. 1997, 1999
 * RMI-IIOP v1.0
 *
 */

package com.sun.tools.corba.se.idl.toJavaPortable;

// NOTES:
// -F46082.51<daz> Remove -stateful feature.
// -D57118   <klr> Fix "narrow" in helper for abstract interface
// -D58889   <klr> re-Fix "narrow" in helper for abstract interface
// -D59383   <klr> 'get_class' in value helper returns value class, not helper.
// -D59413   <klr> Remove Helper interface references for non-value types.
// -D59435   <klr> Remove read_Object, write_Object completely.
// -D59418   <klr> Move read_Value, write_Value to generator's helperRead.

import java.io.PrintWriter;

import java.util.Enumeration;
import java.util.Vector;

import com.sun.tools.corba.se.idl.GenFileStream;
import com.sun.tools.corba.se.idl.InterfaceEntry;
import com.sun.tools.corba.se.idl.MethodEntry;
import com.sun.tools.corba.se.idl.ParameterEntry;
import com.sun.tools.corba.se.idl.SymtabEntry;
import com.sun.tools.corba.se.idl.ValueEntry;
import com.sun.tools.corba.se.idl.ValueBoxEntry;
import com.sun.tools.corba.se.idl.TypedefEntry;
import com.sun.tools.corba.se.idl.InterfaceState;
import com.sun.tools.corba.se.idl.PrimitiveEntry;
import com.sun.tools.corba.se.idl.StructEntry;

/**
 *
 **/
public class Helper implements AuxGen
{
  /**
   * Public zero-argument constructor.
   **/
  public Helper ()
  {
  } // ctor

  /**
   * Generate the helper class.  Provides general algorithm
   * for auxiliary binding generation:
   *
   * 1.) Initialize symbol table and symbol table entry members,
   *     common to all generators.
   * 2.) Initialize members unique to this generator.
   * 3.) Open print stream
   * 4.) Write class heading: package, prologue, class statement, open curly
   * 5.) Write class body: member data and methods
   * 6.) Write class closing: close curly
   * 7.) Close the print stream
   **/
  public void generate (java.util.Hashtable symbolTable, com.sun.tools.corba.se.idl.SymtabEntry entry)
  {
    this.symbolTable = symbolTable;
    this.entry       = entry;
    init ();

    openStream ();
    if (stream == null)
      return;
    writeHeading ();
    writeBody ();
    writeClosing ();
    closeStream ();
  } // generate

  /**
   * Initialize variables unique to this generator.
   **/
  protected void init ()
  {
    helperClass = entry.name () + "Helper";
    if (entry instanceof ValueBoxEntry)
    {
      ValueBoxEntry v = (ValueBoxEntry) entry;
      TypedefEntry member = ((InterfaceState) v.state ().elementAt (0)).entry;
      SymtabEntry mType =  member.type ();

      if (mType instanceof PrimitiveEntry)
        helperType = Util.javaName (entry);
      else
        helperType = Util.javaName (mType);
    }
    else
      helperType = Util.javaName (entry);
  } // init

  /**
   * Open the print stream for subsequent output.
   **/
  protected void openStream ()
  {
    stream = Util.stream (entry, "Helper.java");
  } // openStream

  /**
   * Generate the heading, including package, imports, class statements,
   * and open curly.
   **/
  protected void writeHeading ()
  {
    Util.writePackage (stream, entry, Util.HelperFile);
    Util.writeProlog (stream, stream.name ());

    // Transfer comment to target <30jul1997daz>.
    if (entry.comment () != null)
      entry.comment ().generate ("", stream);

    stream.print ("public final class " + helperClass);
    if (entry instanceof ValueEntry)
      stream.println (" implements org.omg.CORBA.portable.ValueHelper");
    else
      stream.println ();
    stream.println ('{');
  }

  /**
   * Generate members of this class.
   **/
  protected void writeBody ()
  {
    writeInstVars ();
    writeCtors ();
    writeInsert ();
    writeExtract ();
    writeType ();
    writeID ();
    writeRead ();
    writeWrite ();
    if (entry instanceof InterfaceEntry && !(entry instanceof ValueEntry)) {
      writeNarrow ();
      writeUncheckedNarrow ();
    }
    writeHelperInterface ();
    if (entry instanceof ValueEntry)
      writeValueHelperInterface ();
  } // writeBody

  /**
   * Generate members of the Helper interface.
   **/
  protected void writeHelperInterface ()
  {
  } // writeHelperInterface

  /**
   * Generate members of the ValueHelper interface.
   **/
  protected void writeValueHelperInterface ()
  {
    writeGetID ();       // moved for <d59413>
    writeGetType ();     // moved for <d59413>
    writeGetInstance (); // not in ValueHelper interface
    writeGetClass ();
    writeGetSafeBaseIds ();
  } // writeHelperInterface

  /**
   * Generate the closing statements.
   **/
  protected void writeClosing ()
  {
    stream.println ('}');
  }

  /**
   * Write the stream to file by closing the print stream.
   **/
  protected void closeStream ()
  {
    stream.close ();
  }

  /**
   * Generate the instance variables.
   **/
  protected void writeInstVars ()
  {
    stream.println ("  private static String  _id = \"" + Util.stripLeadingUnderscoresFromID (entry.repositoryID ().ID ()) + "\";");
    if (entry instanceof ValueEntry)
    {
      stream.println ();
      stream.println ("  private static " + helperClass + " helper = new " + helperClass + " ();");
      stream.println ();
      stream.println ("  private static String[] _truncatable_ids = {");
      stream.print   ("    _id");

      // Any safe ValueEntry must have a concete value parent.
      // The topmost parent cannot be safe since it doesn't have
      // a concrete parent.
      ValueEntry child = (ValueEntry) entry;
      while (child.isSafe ())
      {
        stream.println(",");
        ValueEntry parent = (ValueEntry)child.derivedFrom ().elementAt (0);
        stream.print("    \"" + Util.stripLeadingUnderscoresFromID (parent.repositoryID ().ID ()) + "\"");
        child = parent;
      }
      stream.println("   };");
    }
    stream.println ();
  } // writeInstVars

  /**
   * Generate the constructors.
   **/
  protected void writeCtors ()
  {
    stream.println ("  public " + helperClass + "()");
    stream.println ("  {");
    stream.println ("  }");
    stream.println ();
  } // writeCtors

  /**
   * Generate the insert method.
   **/
  protected void writeInsert ()
  {
    stream.println ("  public static void insert (org.omg.CORBA.Any a, " + helperType + " that)");
    stream.println ("  {");
    stream.println ("    org.omg.CORBA.portable.OutputStream out = a.create_output_stream ();");
    stream.println ("    a.type (type ());");
    stream.println ("    write (out, that);");
    stream.println ("    a.read_value (out.create_input_stream (), type ());");
    stream.println ("  }");
    stream.println ();
  } // writeInsert

  /**
   * Generate the extract method.
   **/
  protected void writeExtract ()
  {
    stream.println ("  public static " + helperType + " extract (org.omg.CORBA.Any a)");
    stream.println ("  {");
    stream.println ("    return read (a.create_input_stream ());");
    stream.println ("  }");
    stream.println ();
  } // writeExtract

  /**
   * Generate the typecode variable and type method.
   **/
  protected void writeType ()
  {
    boolean canRecurse = entry instanceof ValueEntry
        || entry instanceof ValueBoxEntry
        || entry instanceof StructEntry;
    stream.println ("  private static org.omg.CORBA.TypeCode __typeCode = null;");
    if (canRecurse)
      stream.println ("  private static boolean __active = false;");
    stream.println ("  synchronized public static org.omg.CORBA.TypeCode type ()");
    stream.println ("  {");
    stream.println ("    if (__typeCode == null)");
    stream.println ("    {");
    if (canRecurse) {
    stream.println ("      synchronized (org.omg.CORBA.TypeCode.class)");
    stream.println ("      {");
    stream.println ("        if (__typeCode == null)");
    stream.println ("        {");
    stream.println ("          if (__active)");
    stream.println ("          {");
    stream.println ("            return org.omg.CORBA.ORB.init().create_recursive_tc ( _id );");
    stream.println ("          }");
    stream.println ("          __active = true;");
    ((JavaGenerator)entry.generator ()).helperType (0, "          ", new TCOffsets (), "__typeCode", entry, stream);
    }
    else
    ((JavaGenerator)entry.generator ()).helperType (0, "      ", new TCOffsets (), "__typeCode", entry, stream);

    // Generate body of type() method

    if (canRecurse) {
    stream.println ("          __active = false;");
    stream.println ("        }");
    stream.println ("      }");
    }
    stream.println ("    }");
    stream.println ("    return __typeCode;");
    stream.println ("  }");
    stream.println ();
  } // writeType

  /**
   * Generate the ID method.
   **/
  protected void writeID ()
  {
    stream.println ("  public static String id ()");
    stream.println ("  {");
    stream.println ("    return _id;");
    stream.println ("  }");
    stream.println ();
  } // writeID

  /**
   * Generate the read method.
   **/
  protected void writeRead ()
  {

    boolean isLocalInterface = false;

    if (entry instanceof InterfaceEntry) {
        InterfaceEntry ie = (InterfaceEntry) entry;

        // for #pragma sun_local or sun_localservant, or actual local
        // local interface, set the flag by checking on both
        isLocalInterface = ie.isLocal() | ie.isLocalServant();
    }

    stream.println ("  public static " + helperType + " read (org.omg.CORBA.portable.InputStream istream)");
    stream.println ("  {");
    if ( !isLocalInterface ) { // nonLocal Interface and other types
      ((JavaGenerator)entry.generator ()).helperRead (helperType, entry, stream);
    } else { //Local interface should throw exception
      stream.println ("      throw new org.omg.CORBA.MARSHAL ();");
    }
    stream.println ("  }");
    stream.println ();
  } // writeRead

  /**
   * Generate the write method.
   **/
  protected void writeWrite ()
  {

    boolean isLocalInterface = false;

    if (entry instanceof InterfaceEntry) {
        InterfaceEntry ie = (InterfaceEntry) entry;

        // for #pragma sun_local or sun_localservant, or actual local
        // local interface, set the flag by checking on both
        isLocalInterface = ie.isLocal() | ie.isLocalServant();
    }

    stream.println ("  public static void write (org.omg.CORBA.portable.OutputStream ostream, " + helperType + " value)");
    stream.println ("  {");
    if ( !isLocalInterface ) { // nonLocal Interface and other types
      ((JavaGenerator)entry.generator ()).helperWrite (entry, stream);
    } else { //Local interface should throw exception
      stream.println ("      throw new org.omg.CORBA.MARSHAL ();");
    }
    stream.println ("  }");
    stream.println ();
  } // writeWrite


  /**
   * Generate the narrow method.
   **/
  protected void writeNarrow ()
  {
    writeRemoteNarrow ();
    stream.println ();
  }

  /**
   * Write the narrow() method for a remotable object.
   **/
  protected void writeRemoteNarrow ()
  {
    InterfaceEntry ie = (InterfaceEntry) entry;

    // narrow for LocalObject interface
    if (ie.isLocal ()) {
        writeRemoteNarrowForLocal (false);
        return;
    }

    // narrow for Abstract interface
    if (ie.isAbstract ()) {
        writeRemoteNarrowForAbstract (false);
        return;
    } else {
        // Determine if the non-abstract interface has any abstract parents
        for (int i = 0; i < ie.derivedFrom ().size (); i++) {
            SymtabEntry parent = (SymtabEntry) ie.derivedFrom ().elementAt (i);
            if (((InterfaceEntry) parent).isAbstract ()) {
                writeRemoteNarrowForAbstract (true);
                break;
            }
        }
    }

    stream.println ("  public static " + helperType + " narrow (org.omg.CORBA.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    stream.println ("    else if (obj instanceof " + helperType + ')');
    stream.println ("      return (" + helperType + ")obj;");
    stream.println ("    else if (!obj._is_a (id ()))");
    stream.println ("      throw new org.omg.CORBA.BAD_PARAM ();");
    stream.println ("    else");
    stream.println ("    {");
    stream.println ("      org.omg.CORBA.portable.Delegate delegate = ((org.omg.CORBA.portable.ObjectImpl)obj)._get_delegate ();");
    String stubNameofEntry = stubName ((InterfaceEntry)entry);
    stream.println ("      " + stubNameofEntry + " stub = new " + stubNameofEntry + " ();");
    stream.println ("      stub._set_delegate(delegate);");
    stream.println ("      return stub;");
    stream.println ("    }");
    stream.println ("  }");
  } // writeRemoteNarrow

  /**
   * Write the narrow() method for local interface.
   **/
  private void writeRemoteNarrowForLocal (boolean hasAbstractParent)
  {
    stream.println ("  public static " + helperType + " narrow (org.omg.CORBA.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    stream.println ("    else if (obj instanceof " + helperType + ')');
    stream.println ("      return (" + helperType + ")obj;");
    stream.println ("    else");
    stream.println ("      throw new org.omg.CORBA.BAD_PARAM ();");
    stream.println ("  }");
  } // writeRemoteNarrowForLocal

  /**
   * Write the narrow() method for abstract interface.
   **/
  private void writeRemoteNarrowForAbstract (boolean hasAbstractParent)
  {
    stream.print ("  public static " + helperType + " narrow (java.lang.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    if (hasAbstractParent)
    {
      stream.println ("    else if (obj instanceof org.omg.CORBA.Object)");
      stream.println ("      return narrow ((org.omg.CORBA.Object) obj);");
    }
    else
    {
      stream.println ("    else if (obj instanceof " + helperType + ')');
      stream.println ("      return (" + helperType + ")obj;");
    }

    // If hasAbstractParent is false, then THIS entry must be abstract.
    // This method is also called in case THIS entry is not abstract, but
    // there is an abstract parent.  If this entry is not abstract,
    // it can never narrow to a CORBA object reference.
    if (!hasAbstractParent) { // <d58889>
      String stubNameofEntry = stubName ((InterfaceEntry)entry);

      stream.println ("    else if ((obj instanceof org.omg.CORBA.portable.ObjectImpl) &&");
      stream.println ("             (((org.omg.CORBA.Object)obj)._is_a (id ()))) {");
      stream.println ("      org.omg.CORBA.portable.ObjectImpl impl = (org.omg.CORBA.portable.ObjectImpl)obj ;" ) ;
      stream.println ("      org.omg.CORBA.portable.Delegate delegate = impl._get_delegate() ;" ) ;
      stream.println ("      " + stubNameofEntry + " stub = new " + stubNameofEntry + " ();");
      stream.println ("      stub._set_delegate(delegate);");
      stream.println ("      return stub;" ) ;
      stream.println ("    }" ) ;
    };
    // end <d57118 - check for remotable - klr>

    stream.println ("    throw new org.omg.CORBA.BAD_PARAM ();");
    stream.println ("  }");
    stream.println ();
  } // writeRemoteNarrowForAbstract


  /**
   * Generate the unchecked narrow method.
   **/
  protected void writeUncheckedNarrow ()
  {
    writeUncheckedRemoteNarrow ();
    stream.println ();
  }

  /**
   * Write the unchecked narrow() method for a remotable object.
   **/
  protected void writeUncheckedRemoteNarrow ()
  {
    InterfaceEntry ie = (InterfaceEntry) entry;

    // unchecked narrow for LocalObject interface
    if (ie.isLocal ()) {
        writeRemoteUncheckedNarrowForLocal (false);
        return;
    }

    // unchecked narrow for Abstract interface
    if (ie.isAbstract ()) {
        writeRemoteUncheckedNarrowForAbstract (false);
        return;
    } else {
        // Determine if the non-abstract interface has any abstract parents
        for (int i = 0; i < ie.derivedFrom ().size (); i++) {
            SymtabEntry parent = (SymtabEntry) ie.derivedFrom ().elementAt (i);
            if (((InterfaceEntry) parent).isAbstract ()) {
                writeRemoteUncheckedNarrowForAbstract (true);
                break;
            }
        }
    }

    stream.println ("  public static " + helperType + " unchecked_narrow (org.omg.CORBA.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    stream.println ("    else if (obj instanceof " + helperType + ')');
    stream.println ("      return (" + helperType + ")obj;");
    stream.println ("    else");
    stream.println ("    {");
    stream.println ("      org.omg.CORBA.portable.Delegate delegate = ((org.omg.CORBA.portable.ObjectImpl)obj)._get_delegate ();");
    String stubNameofEntry = stubName ((InterfaceEntry)entry);
    stream.println ("      " + stubNameofEntry + " stub = new " + stubNameofEntry + " ();");
    stream.println ("      stub._set_delegate(delegate);");
    stream.println ("      return stub;");
    stream.println ("    }");
    stream.println ("  }");
  } // writeUncheckedRemoteNarrow

  /**
   * Write the unchecked narrow() method for local interface.
   **/
  private void writeRemoteUncheckedNarrowForLocal (boolean hasAbstractParent)
  {
    stream.println ("  public static " + helperType + " unchecked_narrow (org.omg.CORBA.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    stream.println ("    else if (obj instanceof " + helperType + ')');
    stream.println ("      return (" + helperType + ")obj;");
    stream.println ("    else");
    stream.println ("      throw new org.omg.CORBA.BAD_PARAM ();");
    stream.println ("  }");
  } // writeRemoteUncheckedNarrowForLocal

  /**
   * Write the unchecked narrow() method for abstract interface.
   **/
  private void writeRemoteUncheckedNarrowForAbstract (boolean hasAbstractParent)
  {
    stream.print ("  public static " + helperType + " unchecked_narrow (java.lang.Object obj)");
    stream.println ("  {");
    stream.println ("    if (obj == null)");
    stream.println ("      return null;");
    if (hasAbstractParent)
    {
      stream.println ("    else if (obj instanceof org.omg.CORBA.Object)");
      stream.println ("      return unchecked_narrow ((org.omg.CORBA.Object) obj);");
    }
    else
    {
      stream.println ("    else if (obj instanceof " + helperType + ')');
      stream.println ("      return (" + helperType + ")obj;");
    }

    if (!hasAbstractParent) {
      String stubNameofEntry = stubName ((InterfaceEntry)entry);

      stream.println ("    else if (obj instanceof org.omg.CORBA.portable.ObjectImpl) {");
      stream.println ("      org.omg.CORBA.portable.ObjectImpl impl = (org.omg.CORBA.portable.ObjectImpl)obj ;" ) ;
      stream.println ("      org.omg.CORBA.portable.Delegate delegate = impl._get_delegate() ;" ) ;
      stream.println ("      " + stubNameofEntry + " stub = new " + stubNameofEntry + " ();");
      stream.println ("      stub._set_delegate(delegate);");
      stream.println ("      return stub;" ) ;
      stream.println ("    }" ) ;
    };

    stream.println ("    throw new org.omg.CORBA.BAD_PARAM ();");
    stream.println ("  }");
    stream.println ();
  } // writeRemoteUncheckedNarrowForAbstract


  /**
   * Generate the GetID method.
   **/
  protected void writeGetID ()
  {
    if ( !Util.IDLEntity (entry))
      return;
    stream.println ("  public String get_id ()");
    stream.println ("  {");
    stream.println ("    return _id;");
    stream.println ("  }");
    stream.println ();
  } // writeGetID

  /**
   * Generate the GetType method.
   **/
  protected void writeGetType ()
  {
    if ( !Util.IDLEntity (entry))
      return;
    stream.println ("  public org.omg.CORBA.TypeCode get_type ()");
    stream.println ("  {");
    stream.println ("    return type ();");
    stream.println ("  }");
    stream.println ();
  } // writeGetID

  /**
   * Generate the get_class method.
   **/
  protected void writeGetClass ()
  {
    stream.println ("  public Class get_class ()");
    stream.println ("  {");
    stream.println ("    return " + helperType + ".class;"); //<d59383>
    stream.println ("  }");
    stream.println ();
  } // writeGetClass

  /**
   * Generate the get_instance method.
   **/
  protected void writeGetInstance ()
  {
    stream.println ("  public static org.omg.CORBA.portable.ValueHelper get_instance ()");
    stream.println ("  {");
    stream.println ("    return helper;");
    stream.println ("  }");
    stream.println ();
  } // writeGetInstance

  /**
   * Generate the GetSafeBaseIds method.
   **/
  protected void writeGetSafeBaseIds ()
  {
    stream.println ("  public String[] get_truncatable_base_ids ()");
    stream.println ("  {");
    stream.println ("    return _truncatable_ids;");
    stream.println ("  }");
    stream.println ();
  } // writeGetSafeBaseIds

  /**
   * Return the stub name for the interface entry.
   **/
  protected String stubName (InterfaceEntry entry)
  {
    String name;
    if (entry.container ().name ().equals (""))
      name =  '_' + entry.name () + "Stub";
    else
    {
      name = Util.containerFullName (entry.container ()) + "._" + entry.name () + "Stub";
    }
    return name.replace ('/', '.');
  } // stubName

  protected java.util.Hashtable     symbolTable;
  protected com.sun.tools.corba.se.idl.SymtabEntry entry;
  protected GenFileStream           stream;

  // Unique to this generator
  protected String helperClass;
  protected String helperType;
} // class Helper

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