Package com.sun.jdo.api.persistence.model

Source Code of com.sun.jdo.api.persistence.model.RuntimeModel

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*
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*
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* and Distribution License("CDDL") (collectively, the "License").  You
* may not use this file except in compliance with the License. You can obtain
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* or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
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* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code.  If applicable, add the following below the License
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*/

/*
* RuntimeModel.java
*
* Created on March 10, 2000, 11:05 AM
*/

package com.sun.jdo.api.persistence.model;

import java.io.*;
import java.net.URL;
import java.util.*;
import java.lang.reflect.*;
import java.security.AccessController;
import java.security.PrivilegedAction;

import org.netbeans.modules.dbschema.SchemaElement;
import com.sun.jdo.api.persistence.model.mapping.MappingClassElement;
import com.sun.jdo.spi.persistence.utility.*;

/**
*
* @author raccah
* @version %I%
*/
public class RuntimeModel extends Model
{
  /** Extension of the class file, used to figure out the path for handling
   * the mapping file.
   */
  private static final String CLASS_EXTENSION = "class";      // NOI18N

  /** Constant which represents the prefix of the java package.
   */
  private static final String JAVA_PACKAGE = "java.";        // NOI18N

  /** Constant which represents the serializable interface.
   */
  private static final String SERIALIZABLE = "java.io.Serializable";   //NOI18N

  /** Map of class loader used to find classes and mapping information. Keys
   * are fully qualified class names.
   */
  private HashMap classLoaders = new HashMap();
 
  /** Creates a new RuntimeModel. This constructor should not be called
   * directly; instead, the static instance accesible from the Model class
   * should be used.
   * @see Model#RUNTIME
   */
  protected RuntimeModel ()
  {
    super();
  }

  /** Determines if the specified className represents an interface type.
   * @param className the fully qualified name of the class to be checked
   * @return <code>true</code> if this class name represents an interface;
   * <code>false</code> otherwise.
   */
  public boolean isInterface (String className)
  {
    Class classElement = (Class)getClass(className);
 
    return ((classElement != null) ? classElement.isInterface() : false);
  }

  /** Returns the input stream with the supplied resource name found with
   * the supplied class name.
   * NOTE, this implementation assumes the specified class loader is not null
   * and needs not to be validated. Any validation is done by getMappingClass
   * which is the only caller of this method.
   * @param className the fully qualified name of the class which will
   * be used as a base to find the resource
   * @param classLoader the class loader used to find mapping information
   * @param resourceName the name of the resource to be found
   * @return the input stream for the specified resource, <code>null</code>
   * if an error occurs or none exists
   */
  protected BufferedInputStream getInputStreamForResource (String className,
    ClassLoader classLoader, String resourceName)
  {
    InputStream is = ((className != null) ?
                          classLoader.getResourceAsStream(resourceName) : null);

        BufferedInputStream rc = null;
        if (is != null && !(is instanceof BufferedInputStream)) {
            rc = new BufferedInputStream(is);
        } else {
            rc = (BufferedInputStream)is;
        }
        return rc;
  }

  /** Computes the class name (without package) for the supplied
   * class name.
   * @param className the fully qualified name of the class
   * @return the class name (without package) for the supplied
   * class name
   */
  private String getShortClassName (String className)
  {
     return JavaTypeHelper.getShortClassName(className);
  }

  /** Returns the name of the second to top (top excluding java.lang.Object)
   * superclass for the given class name.
   * @param className the fully qualified name of the class to be checked
   * @return the top non-Object superclass for className,
   * <code>className</code> if an error occurs or none exists
   */
  protected String findPenultimateSuperclass (String className)
  {
    Class classElement = (Class)getClass(className);
    Class objectClass = java.lang.Object.class;
    Class testClass = null;

    if (classElement == null)
      return className;

    while ((testClass = classElement.getSuperclass()) != null)
    {
      if (testClass.equals(objectClass))
        break;

      classElement = testClass;
    }

    return classElement.getName();
  }

  /** Returns the name of the superclass for the given class name.
   * @param className the fully qualified name of the class to be checked
   * @return the superclass for className, <code>null</code> if an error
   * occurs or none exists
   */
  protected String getSuperclass (String className)
  {
    Class classElement = (Class)getClass(className);

    if (classElement != null)
      classElement = classElement.getSuperclass();

    return ((classElement != null) ? classElement.getName() : null);
  }

  /** Returns the MappingClassElement created for the specified class name.
   * This method looks up the class in the internal cache. If not present
   * it loads the corresponding xml file containing the mapping information.
   * @param className the fully qualified name of the mapping class
   * @param classLoader the class loader used to find mapping information
   * @return the MappingClassElement for className,
   * <code>null</code> if an error occurs or none exists
   * @see MappingClassElementImpl#forName
   */
  public MappingClassElement getMappingClass (String className,
    ClassLoader classLoader)
  {
    MappingClassElement mappingClass = null;

    // First check class loader. This has to be done before the super call!
    // Method Model.getMappingClass will check the MappingClassElement cache
    // and will find an entry in the case of a multiple class loader for the
    // same class name. So we have to check the multiple class loader first.
    classLoader = findClassLoader(className, classLoader);
    mappingClass = super.getMappingClass(className, classLoader);
    if ((mappingClass != null) && (classLoader != null))
    {
      // Lookup the SchemElement connected to mappingClass. This reads
      // the .dbschema file using the specified classLoader and stores the
      // SchemaElement in the SchemaElement cache. Any subsequent
      // SchemaElement.forName or TableElement.forName lookups will use
      // the cached version.
      String databaseRoot = mappingClass.getDatabaseRoot();

      // An unmapped mapping class is allowed in which case the
      // databaseRoot will be null (never mapped) or empty
      // (mapped once, unmapped now), but if the databaseRoot is
      // not null or empty and we can't find the schema, throw a
      // RuntimeException to notify the user that something is wrong.
      if (!StringHelper.isEmpty(databaseRoot) &&
        (SchemaElement.forName(databaseRoot, classLoader) == null))
      {
        throw new RuntimeException(I18NHelper.getMessage(
          getMessages(), "dbschema.not_found", // NOI18N
          databaseRoot, className));
      }
    }
 
    return mappingClass;
  }

  /** Returns an unmodifiable copy of the ClassLoader cache.
   * @return unmodifiable ClassLoader cache
   */
  public Map getClassLoaderCache ()
  {
    return Collections.unmodifiableMap(classLoaders);
  }

  /** Removes the classes cached with the specified class loader from all
   * caches. The method iterates the ClassLoader cache to find classes
   * cached with the specified class loader. These classes are removed
   * from the ClassLoader cache, the cache of MappingClassElements and
   * the set of classes known to be non PC. The associated SchemaElements
   * are removed from the SchemaElement cache.
   * @param classLoader used to determine the classes to be removed
   */
  public void removeResourcesFromCaches (ClassLoader classLoader)
  {
    Collection classNames = new HashSet();

    synchronized(classLoaders)
    {
      for (Iterator i = classLoaders.entrySet().iterator(); i.hasNext();)
      {
        Map.Entry next = (Map.Entry)i.next();

        // check the cached class loader
        if (next.getValue() == classLoader)
        {
          // add className to the collection of classNames to be
          // removed
          classNames.add(next.getKey());
          // remove this entry from the classLoaders cache
          i.remove();
        }
      }
    }

    removeResourcesFromCaches(classNames);
  }
 
  /** Creates a file with the given base file name and extension
   * parallel to the supplied class (if it does not yet exist).
   * @param className the fully qualified name of the class
   * @param baseFileName the name of the base file
   * @param extension the file extension
   * @return the output stream for the specified resource, <code>null</code>
   * if an error occurs or none exists
   * @exception IOException if there is some error creating the file
   */
  protected BufferedOutputStream createFile (String className, String baseFileName,
    String extension) throws IOException
  {
    char extensionCharacter = '.';
    File file = getFile(className,
      baseFileName + extensionCharacter + extension);

    if (file == null)
    {
      Class classElement = (Class)getClass(className);

      if (classElement != null)
      {
        // need to find the path before the package name
        String path = classElement.getResource(
          getShortClassName(className) + extensionCharacter +
          CLASS_EXTENSION).getFile();
        int index = path.lastIndexOf(extensionCharacter) + 1;
       
        file = new File(path.substring(0, index) + extension);
        file.createNewFile();
      }
    }
    return ((file != null)
                ? (new BufferedOutputStream(new FileOutputStream(file)))
                : null);
  }

  /** Deletes the file with the given file name which is parallel
   * to the supplied class.
   * @param className the fully qualified name of the class
   * @param fileName the name of the file
   * @exception IOException if there is some error deleting the file
   */
  protected void deleteFile (String className, String fileName)
    throws IOException
  {
    File file = getFile(className, fileName);

    if ((file != null) && file.exists())
      file.delete();
  }

  /** Returns a file with the given file name which is parallel to the
   * supplied class.
   * @param className the fully qualified name of the class
   * @param fileName the name of the file
   * @return the file object for the specified resource, <code>null</code>
   * if an error occurs
   * @exception IOException if there is some error getting the file
   */
  protected File getFile (String className, String fileName)
    throws IOException
  {
    Class classElement = (Class)getClass(className);

    if (classElement != null)
    {
      // need to find the path before the package name
      URL path = classElement.getResource(fileName.substring(
        fileName.lastIndexOf(getShortClassName(className))));

      return ((path != null) ? (new File(path.getFile())) : null);
    }

    return null;
  }

  /** Returns the class element with the specified className.  The class is
   * found using <code>Class.forName</code>.
   * @param className the fully qualified name of the class to be checked
   * @param classLoader the class loader used to find mapping information
   * @return the class element for the specified className, <code>null</code>
   * if an error occurs or none exists
   */
  public Object getClass (String className, ClassLoader classLoader)
  {
    if (className == null)
      return null;
   
    try
    {
      classLoader = findClassLoader(className, classLoader);
      return Class.forName(className, true, classLoader);
    }
    catch (ClassNotFoundException e)
    {
      return null;
    }
  }
   
  /**
   * This method returns the class loader used to find mapping information
   * for the specified className.  If the classLoader argument is not null,
   * the method updates the classLoaders cache and returns the specified
   * classLoader.  Otherwise it checks the cache for the specified className
   * and returns this class loader.  If there is no cached class loader it
   * returns the current class loader.
   * @param className the fully qualified name of the class to be checked
   * @param classLoader the class loader used to find mapping information
   * @return the class loader used to find mapping information for the
   * specified className
   * @exception IllegalArgumentException if there is class loader problem
   */
  protected ClassLoader findClassLoader (String className,
    ClassLoader classLoader) throws IllegalArgumentException
  {
    ClassLoader cached = null;

    if (className == null)
      return null;
    else if (className.startsWith(JAVA_PACKAGE) || isPrimitive(className))
      // Use current class loader for java packages or primitive types
      // - these classes cannot have the multiple class loader conflict
      // - these classes should not show up in the classLoaders map
      return getClass().getClassLoader();

    synchronized (classLoaders)
    {
      cached = (ClassLoader)classLoaders.get(className);

      if (classLoader == null)
      {
        // Case 1: specified class loader is null =>
        // return cached class loader if available, if not
        // take current class loader
        classLoader =
          (cached != null) ? cached : getClass().getClassLoader();
      }
      else if (cached == null)
      {
        // Case 2: specified class loader is NOT null AND
        // no class loader cached for the class name =>
        // put specified class loader in cache
        classLoaders.put(className, classLoader);
      }
      else if (classLoader != cached)
      {
        // Case 3: specified class loader is NOT null AND
        // cache contains class loader for this class name AND
        // both class loaders are not identical =>
        // pontential conflict
        Class clazz = null;
        Class cachedClazz  = null;

        try
        {
          String prop = ClassLoaderStrategy.getStrategy();

          // Load the class using specified and cached class loader.
          // NOTE, do not change the order of the next two lines, the
          // catch block relies on it!
          clazz = Class.forName(className, true, classLoader);
          cachedClazz = Class.forName(className, true, cached);

          if (clazz.getClassLoader() == cachedClazz.getClassLoader())
          {
            // Case 3a: both class loaders are the same =>
            // return it
            return cached;
          }
          else if (ClassLoaderStrategy.MULTIPLE_CLASS_LOADERS_IGNORE.equals(prop))
          {
            // Case 3b: both class loaders are different and
            // the system property is defined as ignore =>
            // ignore the specified class loader and return
            // the cached class loader
            return cached;
          }
          else if (ClassLoaderStrategy.MULTIPLE_CLASS_LOADERS_RELOAD.equals(prop))
          {
            // Case 3c: both class loaders are different and
            // the system property is defined as reload =>
            // discard the cached class loader and replace it
            // by the specified class loader
            removeResourcesFromCaches(cachedClazz.getClassLoader());
            classLoaders.put(className, classLoader);
            return classLoader;
          }
          else
          {
            // Case 3d: both class loaders are different and
            // the system property is defined as error or
            // any other value =>
            // throw exception
            throw new IllegalArgumentException(I18NHelper.getMessage(
              getMessages(), "classloader.multiple", // NOI18N
              className));
          }
        }
        catch (ClassNotFoundException ex)
        {
          // At least one of the class loader could not find the class.
          // Update the classLoader map, if the specified class loader
          // could find it, but the cached could not.
          if ((clazz != null) && (cachedClazz == null))
            classLoaders.put(className, classLoader);
        }
      }
    }

    return classLoader;
  }

  /** Determines if the specified class implements the specified interface.
   * Note, class element is a model specific class representation as returned
   * by a getClass call executed on the same model instance. This
   * implementation expects the class element being a reflection instance.
   * @param classElement the class element to be checked
   * @param interfaceName the fully qualified name of the interface to
   * be checked
   * @return <code>true</code> if the class implements the interface;
   * <code>false</code> otherwise.
   * @see #getClass
   */
  public boolean implementsInterface (Object classElement,
    String interfaceName)
  {
    Class interfaceClass = (Class)getClass(interfaceName);

    if ((classElement == null) || !(classElement instanceof Class) ||
      (interfaceClass == null))
      return false;
   
    return interfaceClass.isAssignableFrom((Class)classElement);
  }

  /** Determines if the class with the specified name declares a constructor.
   * @param className the name of the class to be checked
   * @return <code>true</code> if the class declares a constructor;
   * <code>false</code> otherwise.
   * @see #getClass
   */
  public boolean hasConstructor (final String className)
  {
    final Class classElement = (Class)getClass(className);

    if (classElement != null)
    {
      Boolean b = (Boolean)AccessController.doPrivileged(
        new PrivilegedAction()
      {
        public Object run ()
        {
          return JavaTypeHelper.valueOf(((Class)classElement).
            getDeclaredConstructors().length != 0);
        }
      });

      return b.booleanValue();
    }

    return false;
  }

  /** Returns the constructor element for the specified argument types
   * in the class with the specified name. Types are specified as type
   * names for primitive type such as int, float or as fully qualified
   * class names.
   * @param className the name of the class which contains the constructor
   * to be checked
   * @param argTypeNames the fully qualified names of the argument types
   * @return the constructor element
   * @see #getClass
   */
  public Object getConstructor (final String className, String[] argTypeNames)
  {
    final Class classElement = (Class)getClass(className);

    if (classElement != null)
    {
      final Class[] argTypes = getTypesForNames(argTypeNames);

      return AccessController.doPrivileged(new PrivilegedAction()
      {
        public Object run ()
        {
          try
         
            return ((Class)classElement).getDeclaredConstructor(
              argTypes);
          }
          catch (NoSuchMethodException ex)
          {
            // constructor not found => return null
            return null;
          }
        }
      });
    }

    return null;
  }

  /** Returns the method element for the specified method name and argument
   * types in the class with the specified name. Types are specified as
   * type names for primitive type such as int, float or as fully qualified
   * class names.  Note, the method does not return inherited methods.
   * @param className the name of the class which contains the method
   * to be checked
   * @param methodName the name of the method to be checked
   * @param argTypeNames the fully qualified names of the argument types
   * @return the method element
   * @see #getClass
   */
  public Object getMethod (final String className, final String methodName,
    String[] argTypeNames)
  {
    final Class classElement = (Class)getClass(className);

    if (classElement != null)
    {
      final Class[] argTypes =  getTypesForNames(argTypeNames);

      return AccessController.doPrivileged(new PrivilegedAction()
      {
        public Object run ()
        {
          try
          {
            return classElement.getDeclaredMethod(
              methodName, argTypes);
          }
          catch (NoSuchMethodException ex)
          {
            // method not found => return null
            return null;
          }
        }
      });
    }

    return null;
  }

  /** Returns the string representation of type of the specified element.
   * If element denotes a field, it returns the type of the field.
   * If element denotes a method, it returns the return type of the method.
   * Note, element is either a field element as returned by getField, or a
   * method element as returned by getMethod executed on the same model
   * instance. This implementation expects the element being a reflection
   * instance.
   * @param element the element to be checked
   * @return the string representation of the type of the element
   * @see #getField
   * @see #getMethod
   */
  public String getType (Object element)
  {
    return getNameForType(getTypeObject(element));
  }

  /** Returns a list of names of all the declared field elements in the
   * class with the specified name.
   * @param className the fully qualified name of the class to be checked
   * @return the names of the field elements for the specified class
   */
  public List getFields (String className)
  {
    List returnList = new ArrayList();
    final Class classElement = (Class)getClass(className);
   
    if (classElement != null)
    {
      Field[] fields = (Field[]) AccessController.doPrivileged(
        new PrivilegedAction()
      {
        public Object run ()
        {
          return classElement.getDeclaredFields();
        }
      });
      int i, count = fields.length;

      for (i = 0; i < count; i++)
        returnList.add(fields[i].getName());
    }

    return returnList;
  }

  /** Returns the field element for the specified fieldName in the class
   * with the specified className.
   * @param className the fully qualified name of the class which contains
   * the field to be checked
   * @param fieldName the name of the field to be checked
   * @return the field element for the specified fieldName
   */
  public Object getField (String className, final String fieldName)
  {
    final Class classElement = (Class)getClass(className);

    if (classElement != null)
    {
      return AccessController.doPrivileged(new PrivilegedAction()
      {
        public Object run ()
        {
          try
          {
            return classElement.getDeclaredField(fieldName);
          }
          catch (NoSuchFieldException e)
          {
            // field not found => return null;
            return null;
          }
        }
      });
    }

    return null;
  }

  /** Determines if the specified field element has a serializable type.
   * A type is serializable if it is a primitive type, a class that implements
   * java.io.Serializable or an interface that inherits from
   * java.io.Serializable.
   * Note, the field element is a model specific field representation as
   * returned by a getField call executed on the same model instance. This
   * implementation expects the field element being a reflection instance.
   * @param fieldElement the field element to be checked
   * @return <code>true</code> if the field element has a serializable type;
   * <code>false</code> otherwise.
   * @see #getField
   */
  public boolean isSerializable (Object fieldElement)
  {
    Class type = getTypeObject(fieldElement);

    // check if the topmost element type is serializable
    while ((type != null) && type.isArray())
      type = type.getComponentType();

    return ((type != null) ?
      (type.isPrimitive() || implementsInterface(type, SERIALIZABLE)) :
      false);
  }

  /** Determines if a field with the specified fieldName in the class
   * with the specified className is an array.
   * @param className the fully qualified name of the class which contains
   * the field to be checked
   * @param fieldName the name of the field to be checked
   * @return <code>true</code> if this field name represents a java array
   * field; <code>false</code> otherwise.
   * @see #getFieldType
   */
  public boolean isArray (String className, String fieldName)
  {
    Object fieldElement = getField(className, fieldName);

    return ((fieldElement != null) ?
      getTypeObject(fieldElement).isArray() : false);
  }

  /** Returns the string representation of declaring class of
   * the specified member element.  Note, the member element is
   * either a class element as returned by getClass, a field element
   * as returned by getField, a constructor element as returned by
   * getConstructor, or a method element as returned by getMethod
   * executed on the same model instance.  This implementation
   * expects the member element to be a reflection instance.
   * @param memberElement the member element to be checked
   * @return the string representation of the declaring class of
   * the specified memberElement
   * @see #getClass
   * @see #getField
   * @see #getConstructor
   * @see #getMethod
   */
  public String getDeclaringClass (Object memberElement)
  {
    Class classElement = null;

    if ((memberElement != null) && (memberElement instanceof Member))
      classElement = ((Member)memberElement).getDeclaringClass();

    return ((classElement != null) ? classElement.getName() : null);
  }

  /** Returns the modifier mask for the specified member element.
   * Note, the member element is either a class element as returned by
   * getClass, a field element as returned by getField, a constructor element
   * as returned by getConstructor, or a method element as returned by
   * getMethod executed on the same model instance.  This implementation
   * expects the member element to be a reflection instance.
   * @param memberElement the member element to be checked
   * @return the modifier mask for the specified memberElement
   * @see java.lang.reflect.Modifier
   * @see #getClass
   * @see #getField
   * @see #getConstructor
   * @see #getMethod
   */
  public int getModifiers (Object memberElement)
  {
    int modifiers = 0;
   
    if (memberElement != null)
    {
      if (memberElement instanceof Class)
      {
        modifiers = ((Class)memberElement).getModifiers();
      }
      else if (memberElement instanceof Member)
      {
        modifiers = ((Member)memberElement).getModifiers();
      }
    }

    return modifiers;
  }

  /** Returns the Class type of the specified element.
   * If element denotes a field, it returns the type of the field.
   * If element denotes a method, it returns the return type of the method.
   * Note, element is either a field element as returned by getField, or a
   * method element as returned by getMethod executed on the same model
   * instance.
   * @param element the element to be checked
   * @return the Class type of the element
   * @see #getField
   * @see #getMethod
   */
  protected Class getTypeObject (Object element)
  {
    Class type = null;

    if (element != null)
    {
      if (element instanceof Field)
        type = ((Field)element).getType();
      else if (element instanceof Method)
        type = ((Method)element).getReturnType();
    }

    return type;
  }

  private String getNameForType (Class type)
  {
    String typeName = null;

    if (type != null)
    {
      if (type.isArray())
      {
        typeName = getNameForType(
          type.getComponentType()) + "[]"// NOI18N
      }
      else
        typeName = type.getName();
    }

    return typeName;
  }

  /** Converts the array of type names into an array of Class objects.
   */
  private Class[] getTypesForNames (String[] typeNames)
  {
    Class[] classes = new Class[typeNames.length];

    for (int i = 0; i < classes.length; i++)
      classes[i] = getTypeForName(typeNames[i]);

    return classes;
  }

  /** Converts the specified type name into its corresponding java.lang.Class
   * representation.
   */
  private Class getTypeForName (String typeName)
  {
    Class clazz = JavaTypeHelper.getPrimitiveClass(typeName);

    if (clazz == null)
      clazz = (Class)getClass(typeName);

    return clazz;
  }
}
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Related Classes of com.sun.jdo.api.persistence.model.RuntimeModel

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