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Java example source code file (loaderConstraints.hpp)

This example Java source code file (loaderConstraints.hpp) 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

classloaderdata, handle, hashtableentry, klass, loaderconstraintentry, loaderconstraintentry\*, loaderconstraintentry\*\*, loaderconstrainttable, null, placeholdertable, product, share_vm_classfile_loaderconstraints_hpp, symbol, vmstructs

The loaderConstraints.hpp Java example source code

/*
 * Copyright (c) 2003, 2012, 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.
 *
 * 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.
 *
 */

#ifndef SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP
#define SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP

#include "classfile/dictionary.hpp"
#include "classfile/placeholders.hpp"
#include "utilities/hashtable.hpp"

class LoaderConstraintEntry;
class Symbol;

class LoaderConstraintTable : public Hashtable<Klass*, mtClass> {
  friend class VMStructs;
private:

  enum Constants {
    _loader_constraint_size = 107,                     // number of entries in constraint table
    _nof_buckets            = 1009                     // number of buckets in hash table
  };

  LoaderConstraintEntry** find_loader_constraint(Symbol* name,
                                                 Handle loader);

public:

  LoaderConstraintTable(int nof_buckets);

  LoaderConstraintEntry* new_entry(unsigned int hash, Symbol* name,
                                   Klass* klass, int num_loaders,
                                   int max_loaders);
  void free_entry(LoaderConstraintEntry *entry);

  LoaderConstraintEntry* bucket(int i) {
    return (LoaderConstraintEntry*)Hashtable<Klass*, mtClass>::bucket(i);
  }

  LoaderConstraintEntry** bucket_addr(int i) {
    return (LoaderConstraintEntry**)Hashtable<Klass*, mtClass>::bucket_addr(i);
  }

  // Enhanced Class Redefinition support
  void classes_do(KlassClosure* f);

  // Check class loader constraints
  bool add_entry(Symbol* name, Klass* klass1, Handle loader1,
                                    Klass* klass2, Handle loader2);

  // Note:  The main entry point for this module is via SystemDictionary.
  // SystemDictionary::check_signature_loaders(Symbol* signature,
  //                                           Handle loader1, Handle loader2,
  //                                           bool is_method, TRAPS)

  Klass* find_constrained_klass(Symbol* name, Handle loader);

  // Class loader constraints

  void ensure_loader_constraint_capacity(LoaderConstraintEntry *p, int nfree);
  void extend_loader_constraint(LoaderConstraintEntry* p, Handle loader,
                                Klass* klass);
  void merge_loader_constraints(LoaderConstraintEntry** pp1,
                                LoaderConstraintEntry** pp2, Klass* klass);

  bool check_or_update(instanceKlassHandle k, Handle loader,
                              Symbol* name);


  void purge_loader_constraints();

  void verify(Dictionary* dictionary, PlaceholderTable* placeholders);
#ifndef PRODUCT
  void print();
#endif
};

class LoaderConstraintEntry : public HashtableEntry<Klass*, mtClass> {
  friend class VMStructs;
private:
  Symbol*                _name;                   // class name
  int                    _num_loaders;
  int                    _max_loaders;
  // Loader constraints enforce correct linking behavior.
  // Thus, it really operates on ClassLoaderData which represents linking domain,
  // not class loaders.
  ClassLoaderData**              _loaders;                // initiating loaders

public:

  Klass* klass() { return literal(); }
  Klass** klass_addr() { return literal_addr(); }
  void set_klass(Klass* k) { set_literal(k); }

  LoaderConstraintEntry* next() {
    return (LoaderConstraintEntry*)HashtableEntry<Klass*, mtClass>::next();
  }

  LoaderConstraintEntry** next_addr() {
    return (LoaderConstraintEntry**)HashtableEntry<Klass*, mtClass>::next_addr();
  }
  void set_next(LoaderConstraintEntry* next) {
    HashtableEntry<Klass*, mtClass>::set_next(next);
  }

  Symbol* name() { return _name; }
  void set_name(Symbol* name) {
    _name = name;
    if (name != NULL) name->increment_refcount();
  }

  int num_loaders() { return _num_loaders; }
  void set_num_loaders(int i) { _num_loaders = i; }

  int max_loaders() { return _max_loaders; }
  void set_max_loaders(int i) { _max_loaders = i; }

  ClassLoaderData** loaders() { return _loaders; }
  void set_loaders(ClassLoaderData** loaders) { _loaders = loaders; }

  ClassLoaderData* loader_data(int i) { return _loaders[i]; }
  void set_loader_data(int i, ClassLoaderData* p) { _loaders[i] = p; }
  // convenience
  void set_loader(int i, oop p);
};

#endif // SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP

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