JP.co.Hitachi.soft.jvm.MemoryArea

Class ExplicitMemory

java.lang.Object

JP.co.Hitachi.soft.jvm.MemoryArea.MemoryArea

JP.co.Hitachi.soft.jvm.MemoryArea.ExplicitMemory

Direct Known Subclasses:

BasicExplicitMemory

public abstract class ExplicitMemory
extends MemoryArea

This is an abstract class that indicates the Explicit memory block. This class defines the processing in BasicExplicitMemory.

Method Summary

Modifier and Type	Method and Description
static int	countExplicitMemories() Returns the number of Explicit memory blocks in the Explicit heap.
long	freeMemory() Returns the memory size that can be used by Explicit memory blocks.
static java.lang.management.MemoryUsage	getMemoryUsage() Returns the usage state of the Explicit heap.
boolean	isActive() Returns whether or not the Explicit memory block indicated by the object can be processed.
boolean	isReclaimed() Returns whether or not the Explicit memory block indicated by the object is in the reserved for release state or the released state.
java.lang.Object	newArray(java.lang.Class type, int length) Directly creates an array instance of the length specified in the parameter length of the class that is specified in the parameter type of the Explicit memory block indicated by the object.
java.lang.Object	newArray(java.lang.Class type, int[] dimensions) Directly creates an array instance with a dimension dimensions.length in the Explicit memory block indicated by the object.
java.lang.Object	newInstance(java.lang.Class type) Directly creates the instances of the class indicated by the parameter type in the Explicit memory block indicated by the object.
java.lang.Object	newInstance(java.lang.Class type, java.lang.Object... args) Directly creates the instances of the class indicated by the parameter type in the Explicit memory block.
java.lang.Object	newInstance(java.lang.reflect.Constructor cons, java.lang.Object... args) Executes the constructor indicated by the parameter cons in the parameter args, and then directly creates the instance in the Explicit memory block indicated by the object.
static void	reclaim(ExplicitMemory... areas) Reserves the release processing for all the elements of the parameter areas.
static void	reclaim(ExplicitMemory area) If it is judged by the common error check that the processing can be executed when the parameter area is other than null, execute the exclusion processing in the parameter area, and then reserve the Explicit memory block indicated by the parameter area for the release.
static void	reclaim(ExplicitMemory area0, ExplicitMemory area1) Reserves the release processing for the Explicit memory blocks indicated by the parameter area0 and area1.
static void	reclaim(java.lang.Iterable<ExplicitMemory> areas) Reserves the release processing for all the elements of the parameter areas.
void	setName(java.lang.String name) Sets up a name for the Explicit memory block.
java.lang.String	toString() Returns the string expression of the object.
long	totalMemory() Returns the total reserved size of the Explicit memory block.
long	usedMemory() Returns the used memory size of the Explicit memory block.

Methods inherited from class JP.co.Hitachi.soft.jvm.MemoryArea.MemoryArea

getName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

setName

public void setName(java.lang.String name)
             throws java.lang.NullPointerException

Sets up a name for the Explicit memory block. The parameter name is set up in the instance field that indicates the name of this object, as the name of the Explicit memory block indicated by the object. This name is mainly set up for the purpose of debugging. The specified value is displayed in the event log or the thread dump.

Note: The names are not unique because the same name can be set up in multiple ExplicitMemory.

Specified by:

setName in class MemoryArea

Parameters:

name - This parameter specifies the string that indicates the name to be set up.

Throws:

java.lang.NullPointerException - The value of the parameter name is null.

isActive

public boolean isActive()

Returns whether or not the Explicit memory block indicated by the object can be processed.

Returns:

This method returns the state of the Explicit memory block indicated by the object, in the following Boolean types.

true:The Explicit memory block can be processed. This value is returned for an enabled Explicit memory block, when the substate is Enable.
false:The Explicit memory block cannot be processed. This value is returned in either of the following cases.

• A disabled Explicit memory block
• An enabled Explicit memory block, when the substate is Disable

Note: Once the ExplicitMemory is disabled, it cannot be enabled again.

newInstance

public java.lang.Object newInstance(java.lang.Class type)
                             throws java.lang.InstantiationException,
                                    java.lang.IllegalAccessException,
                                    java.lang.reflect.InvocationTargetException,
                                    java.lang.NoSuchMethodException,
                                    java.lang.SecurityException,
                                    InaccessibleMemoryAreaException,
                                    java.lang.ExceptionInInitializerError,
                                    java.lang.NullPointerException

Directly creates the instances of the class indicated by the parameter type in the Explicit memory block indicated by the object. Only the instances of the class specified in the parameter are created in the Explicit memory block. The objects created through the initialization by the constructor of the instances of the class specified in the parameter are created in the Java heap. type is same as Class.newInstance() for this object, however some part is different.

Specified by:

newInstance in class MemoryArea

Parameters:

type - This is the class of the array instance to be created directly.

Returns:

This method returns the reference to the instances created in the Explicit memory block indicated by the object. If it is judged that processing cannot be executed by performing the common error check, invoke the Class.newInstance() method by considering the parameter type as a receiver, and return that result. For details on common error check, see Common Error Check.

Throws:

java.lang.NullPointerException - Either the parameter type or the class indicated by the parameter type is null.

java.lang.SecurityException - This exception is thrown when SecurityManager exists, and when any of the following conditions hold true.

• The invocation of s.checkMemberAccess(type, Member.PUBLIC) does not allow access to this constructor.
• The class loader at the calling side is different.
• The invocation of the class loader higher than the current class loader and also the invocation of s.checkPackageAccess() do not allow access to the package of this class.

java.lang.NoSuchMethodException - No constructor, without a public parameter, exists in either the parameter type or the class indicated by the parameter type.

java.lang.ExceptionInInitializerError - An attempt to initialize the parameter type or the class indicated by the parameter type has failed.

java.lang.InstantiationException - The parameter type or the class indicated by the parameter type is either an abstract class or an interface.

java.lang.reflect.InvocationTargetException - An exception occurred during the execution of the parameter type or the constructor of the class indicated by the parameter type.

java.lang.IllegalAccessException - The class or its nullary constructor cannot be accessed.

InaccessibleMemoryAreaException - This functionality is not supported.

newInstance

public java.lang.Object newInstance(java.lang.Class type,
                                    java.lang.Object... args)
                             throws java.lang.InstantiationException,
                                    java.lang.IllegalAccessException,
                                    java.lang.IllegalArgumentException,
                                    java.lang.reflect.InvocationTargetException,
                                    java.lang.NoSuchMethodException,
                                    java.lang.SecurityException,
                                    InaccessibleMemoryAreaException,
                                    java.lang.ExceptionInInitializerError,
                                    java.lang.NullPointerException

Directly creates the instances of the class indicated by the parameter type in the Explicit memory block. The value specified in the parameter args is passed as an argument of the constructor that creates the instances. The objects created through the initialization by the constructor of the instances of the class specified in the parameter are created in the Java heap.

Note: We recommend that you add a public class in the parameter type. You cannot invoke a constructor in which the primitive type is assumed as an argument. To invoke a constructor in which the primitive type is assumed as an argument, use the newInstance(Constructor, Object...). A coding example in which the newInstance newInstance(Constructor, Object...) is used is as follows.

   
    import JP.co.Hitachi.soft.jvm.MemoryArea.*;
    import java.lang.reflect.*;
    public class test1 {
      public static void main(String[] args) throws Exception {
        ExplicitMemory em = new BasicExplicitMemory();
        TheClass obj = null;
        
        Constructor cons = TheClass.class.getConstructor(
                                     new Class[]{int.class}
                           );
        // Execution successful
        obj = (TheClass)em.newInstance(cons,1);

        // NoSuchMethodException is thrown
        obj = (TheClass)em.newInstance(TheClass.class,1);
      }
    }
   
  

Specified by:

newInstance in class MemoryArea

Parameters:

type - This is the class of the array instance to be created directly.

args - This is a parameter that is passed to the constructor.

Returns:

This method returns the reference to the instances created in the Explicit memory block indicated by the object. If it is judged that processing cannot be executed after performing the common error check, acquire the java.lang.reflect. Constructor instance as type.getConstructor(arg_types#). In this case, consider java.lang.reflect.Constructor as a receiver, parameter args as a parameter, invoke the java.lang.reflect.Constructor.newInstance(Object... initargs) method, and return the result. For details on common error check, see Common Error Check.

Note :arg_types is a class array in which the results of invocation of Object.getClass() as the object are assumed as the elements of the parameter args.

Throws:

java.lang.NullPointerException - The value of either one of the parameters or both the parameters type and args is null.

java.lang.SecurityException - This exception is thrown when SecurityManager exists, and when any of the following conditions hold true.

• When the number of real parameters and virtual parameters is different
• When the lap release conversion of the primitive arguments fails
• When the parameter value cannot be converted to the corresponding virtual parameter type after lap release of the primitive argument
• When the constructor is related to the enumeration type

java.lang.NoSuchMethodException - A public constructor having a parameter of the same type as the elements of the parameter args does not exist in the class indicated by the parameter type.

java.lang.ExceptionInInitializerError - An attempt to initialize the parameter type or the class indicated by the parameter type has failed.

java.lang.InstantiationException - The parameter type or the class indicated by the parameter type is either an abstract class or an interface.

java.lang.reflect.InvocationTargetException - An exception occurred during the execution of the parameter type or the constructor of the class indicated by the parameter type.

InaccessibleMemoryAreaException - This functionality is not supported.

java.lang.IllegalAccessException - The class or its nullary constructor cannot be accessed.

java.lang.IllegalArgumentException - This exception is thrown in each of the conditions.

• The invocation of s.checkMemberAccess(type, Member.PUBLIC) does not allow access to this constructor.
• The class loader at the calling side is different.
• The invocation of the class loader is higher than the current class loader, and also the invocation of s.checkPackageAccess() does not allow access to the package of this class.

newInstance

public java.lang.Object newInstance(java.lang.reflect.Constructor cons,
                                    java.lang.Object... args)
                             throws java.lang.InstantiationException,
                                    java.lang.IllegalAccessException,
                                    java.lang.IllegalArgumentException,
                                    java.lang.reflect.InvocationTargetException,
                                    InaccessibleMemoryAreaException,
                                    java.lang.ExceptionInInitializerError,
                                    java.lang.NullPointerException

Executes the constructor indicated by the parameter cons in the parameter args, and then directly creates the instance in the Explicit memory block indicated by the object. Only the instances of the class specified in the parameter are created in the Explicit memory block. The objects created through initialization by the constructor of the instances of class specified in the parameter are created in the Java heap.

Note: We recommend that you add the constructor of a public class in the parameter cons.

Specified by:

newInstance in class MemoryArea

Parameters:

cons - This parameter specifies the constructor of the array instance to be created directly.

args - This is a parameter that is passed to the constructor.

Returns:

This method returns the reference to the instances created in the Explicit memory block indicated by the method. If it is judged that processing cannot be executed by performing the common error check, invoke parameter cons of java.lang.reflect.Constructor.newInstance(Object... initargs) as this object, parameter args as a parameter, and return that result. For details on common error check, see Common Error Check.

Throws:

java.lang.NullPointerException - The value of either one or both the parameters cons and args is null.

java.lang.ExceptionInInitializerError - An attempt to initialize the class with the constructor indicated by the parameter cons has failed.

java.lang.InstantiationException - The constructor indicated by the parameter cons is an abstract class.

java.lang.IllegalArgumentException - The parameter of the constructor indicated by the parameter cons does not match the parameter args.

java.lang.IllegalAccessException - The base constructor cannot be accessed because Java language access control is executed in the Constructor object.

java.lang.reflect.InvocationTargetException - An exception occurred during the execution of the constructor indicated by the parameter cons or parameter args.

InaccessibleMemoryAreaException - This functionality is not supported.

newArray

public java.lang.Object newArray(java.lang.Class type,
                                 int length)
                          throws InaccessibleMemoryAreaException,
                                 java.lang.NegativeArraySizeException,
                                 java.lang.IllegalArgumentException,
                                 java.lang.NullPointerException

Directly creates an array instance of the length specified in the parameter length of the class that is specified in the parameter type of the Explicit memory block indicated by the object.

Specified by:

newArray in class MemoryArea

Parameters:

type - This parameter specifies the class of the array instance to be created directly.

length - This parameter specifies the length of the array instance to be created directly.

Returns:

This method directly creates an array of the type type in the Explicit memory block indicated by the object, and then returns the reference. The length of the array is as specified in length. If it is judged that processing cannot be executed by performing the common error check, invoke java.lang.reflect.Array.newInstance(Class,componentType,int length) by the parameter type and parameter length, and return that result. For details on common error check, see Common Error Check.

Throws:

java.lang.NullPointerException - The parameter type is null.

java.lang.NegativeArraySizeException - The parameter length is 0 or less than 0.

java.lang.IllegalArgumentException - An array class for which the parameter length is more than 0 and the parameter type is more than 255 dimensions or the array class having the type Void.TYPE.

InaccessibleMemoryAreaException - This functionality is not supported.

newArray

public java.lang.Object newArray(java.lang.Class type,
                                 int[] dimensions)
                          throws InaccessibleMemoryAreaException,
                                 java.lang.IllegalArgumentException,
                                 java.lang.NegativeArraySizeException,
                                 java.lang.NullPointerException

Directly creates an array instance with a dimension dimensions.length in the Explicit memory block indicated by the object. Note that the number of elements of the nth dimension of the class indicated by the parameter type is dimensions[n-1].

Specified by:

newArray in class MemoryArea

Parameters:

type - This parameter specifies the class of the array instance to be created directly.

dimensions - This parameter specifies the number of dimensions and elements of the array instance to be created directly.

Returns:

This method directly creates an array object with the dimension dimensions.length and the type type, wherein the number of elements of the nth dimension is dimensions[n-1], in the Explicit memory block indicated by the object, and then returns the reference. If it is judged that processing cannot be executed by performing the common error check, invoke java.lang.reflect.Array.newInstance (Class componentType,int[] dimensions) by the parameter type and parameter dimensions, and return that result. For details on common error check, see Common Error Check.

Throws:

java.lang.NullPointerException - The value of either one or both the parameters dimensions and type is null.

java.lang.NegativeArraySizeException - The parameter dimension has an element with a negative value.

java.lang.IllegalArgumentException - This exception is thrown in any of the following cases.

• When dimensions.length of the parameter dimensions is less than 0 or more than 255
• When the total of the number of dimensions of the parameter type and dimensions.length of the parameter dimensions is more than 255
• When the parameter type is Void.TYPE

InaccessibleMemoryAreaException - This functionality is not supported.

freeMemory

public long freeMemory()
                throws InaccessibleMemoryAreaException

Returns the memory size that can be used by Explicit memory blocks.

Specified by:

freeMemory in class MemoryArea

Returns:

The common error check is performed and then this method returns either of the following values. For details on common error check, see Common Error Check.

0:Returned when the API processing cannot be performed.
The memory size (number of bytes) that can be used for the Explicit memory block indicated by this object：When you can perform API processing, the memory size that can be used for the Explicit memory block, indicated by the object, is returned in the long type.

Throws:

InaccessibleMemoryAreaException - This functionality is not supported.

usedMemory

public long usedMemory()
                throws InaccessibleMemoryAreaException

Returns the used memory size of the Explicit memory block.

Specified by:

usedMemory in class MemoryArea

Returns:

The used memory size (number of bytes) of the Explicit memory block indicated by the object is returned to the long type. When it is judged by the common error check that the processing cannot be executed, 0 is returned. For details on common error check, see Common Error Check.

Throws:

InaccessibleMemoryAreaException - This functionality is not supported.

totalMemory

public long totalMemory()
                 throws InaccessibleMemoryAreaException

Returns the total reserved size of the Explicit memory block.

Specified by:

totalMemory in class MemoryArea

Returns:

The common error check is performed, and then this method returns either of the following values. For details on common error check, see Common Error Check.

0:Returned when the API processing cannot be performed.
Total reserved memory size (number of bytes) of the Explicit memory block indicated by the object： When the API processing can be performed, the memory size that can be used by the Explicit memory block indicated by the object is returned to the long type.

Throws:

InaccessibleMemoryAreaException - This functionality is not supported.

reclaim

public static void reclaim(ExplicitMemory area)
                    throws InaccessibleMemoryAreaException

If it is judged by the common error check that the processing can be executed when the parameter area is other than null, execute the exclusion processing in the parameter area, and then reserve the Explicit memory block indicated by the parameter area for the release. The processing is not executed in the following cases.

• When the parameter area is null
• When it is judged by the common error check that the processing cannot be executed

Note: This method only reserves the release processing, and does not actually perform the release processing. When the option HitachiExplicitMemoryAutoReclaim is ON (-XX:+HitachiExplicitMemoryAutoReclaim is specified), the Explicit memory block after the automatic release will execute the same operation as is executed by the Explicit memory block that is generated by the explicit memory management automatic deployment settings file. If you do not want this operation to be performed, set the option HitachiExplicitMemoryAutoReclaim to OFF (-XX:+HitachiExplicitMemoryAutoReclaim is not specified).

Parameters:

area - This parameter specifies the Explicit memory block for which the release processing is to be reserved.

Throws:

InaccessibleMemoryAreaException - This functionality is not supported.

reclaim

public static void reclaim(ExplicitMemory area0,
                           ExplicitMemory area1)
                    throws InaccessibleMemoryAreaException

Reserves the release processing for the Explicit memory blocks indicated by the parameter area0 and area1. Execute the processing that is executed when ExplicitMemory.reclaim(ExplicitMemory area) is invoked using the parameter area0 and area1 as the parameters. The processing order of the parameter area0 and area1 is not defined. If an exception occurs during the processing for one parameter, that exception will be thrown. If the other parameter is unprocessed, the processing will not be executed.

Note: This method only reserves the release processing, and does not actually perform the release processing. When the option HitachiExplicitMemoryAutoReclaim is ON (-XX:+HitachiExplicitMemoryAutoReclaim is specified), the Explicit memory block after the automatic release will execute the same operation as is executed by the Explicit memory block that is generated by the explicit memory management automatic deployment settings file. If you do not want this operation to be performed, set the option HitachiExplicitMemoryAutoReclaim to OFF (-XX:+HitachiExplicitMemoryAutoReclaim is not specified).

Parameters:

area0 - This parameter specifies the Explicit memory block 1 for which the release processing is to be reserved.

area1 - This parameter specifies the Explicit memory block 2 for which the release processing is to be reserved.

Throws:

InaccessibleMemoryAreaException - This functionality is not supported.

reclaim

public static void reclaim(ExplicitMemory... areas)
                    throws InaccessibleMemoryAreaException,
                           java.lang.NullPointerException

Reserves the release processing for all the elements of the parameter areas. When the parameter areas is other than null, execute the same processing that is executed when ExplicitMemory.reclaim(ExplicitMemory area) is invoked assuming the elements as the parameters, for all the elements of the parameter areas. The order of the elements, for which the processing is performed, is not defined. If an exception occurs during the processing for any element, that exception will be thrown. The processing is not executed for the elements that are not processed until the exception is thrown.

Note: This method only reserves the release processing, and does not actually perform the release processing. When the option HitachiExplicitMemoryAutoReclaim is ON (-XX:+HitachiExplicitMemoryAutoReclaim is specified), the Explicit memory block after the automatic release will execute the same operation as is executed by the Explicit memory block that is generated by the explicit memory management automatic deployment settings file. If you do not want this operation to be performed, set the option HitachiExplicitMemoryAutoReclaim to OFF (-XX:+HitachiExplicitMemoryAutoReclaim is not specified).

Parameters:

areas - This parameter specifies the array containing the Explicit memory block for which the release processing is to be reserved in the elements.

Throws:

java.lang.NullPointerException - The parameter areas is null.

InaccessibleMemoryAreaException - This functionality is not supported.

reclaim

public static void reclaim(java.lang.Iterable<ExplicitMemory> areas)
                    throws InaccessibleMemoryAreaException,
                           java.lang.NullPointerException

Reserves the release processing for all the elements of the parameter areas. When the parameter areas is other than null, execute the same processing that is executed when ExplicitMemory.reclaim(ExplicitMemory area) is invoked assuming the elements as the parameters, for all the elements of the parameter areas. The order of the elements for which the processing is performed is not defined. If an exception occurs during the processing for any element, that exception will be thrown. Processing is not executed for the elements that are not processed until the exception is thrown.

Note: This method only reserves the release processing, and does not actually perform the release processing. When the option HitachiExplicitMemoryAutoReclaim is ON (-XX:+HitachiExplicitMemoryAutoReclaim is specified), the Explicit memory block after the automatic release will execute the same operation as is executed by the Explicit memory block that is generated by the explicit memory management automatic deployment settings file. If you do not want this operation to be performed, set the option HitachiExplicitMemoryAutoReclaim to OFF (-XX:+HitachiExplicitMemoryAutoReclaim is not specified).

Parameters:

areas - This parameter specifies the iterator of the Explicit memory block for which the release processing is reserved.

Throws:

java.lang.NullPointerException - The value of the parameter areas is null.

InaccessibleMemoryAreaException - This functionality is not supported.

isReclaimed

public boolean isReclaimed()

Returns whether or not the Explicit memory block indicated by the object is in the reserved for release state or the released state.

Returns:

This method returns the state of the Explicit memory block indicated by the object, in the following boolean types.

true:either in the reserve for release state or the released state.
false:This value is returned when the Explicit memory block indicated by the object is in the enabled state.

getMemoryUsage

public static java.lang.management.MemoryUsage getMemoryUsage()

Returns the usage state of the Explicit heap.

Returns:

This method returns the reference to the java.lang.management.MemoryUsage instance that maintains the usage state of the Explicit heap as a field, in the form of the following values.

init:This is the initial value of the Explicit heap. This value is always 0.
used:This is the memory size (number of bytes) being used in the Explicit heap.
committed:This is the reserved size (number of bytes) of the Explicit heap.
max:This is the value (number of bytes) of the maximum Explicit heap size specified by -XX:HitachiExplicitHeapMaxSize. However, when the option HitachiUseExplicitMemory is OFF (when -XX:+HitachiUseExplicitMemory is specified), 0 is returned.

Note: The value contained in the MemoryUsage instance is the value at the point of time when getMemoryUsage() is invoked. This value might be different from the actual value when each field is read out from the MemoryUsage instance.

countExplicitMemories

public static int countExplicitMemories()

Returns the number of Explicit memory blocks in the Explicit heap. If an Explicit memory block is already released or is disabled, that Explicit memory block is not counted.

Note:

• number of blocks that are already reserved for release, the number might change over time.
• This method is not used to count the number of ExplicitMemory instances, but instead it counts the actual number of Explicit memory blocks.

Returns:

This method counts the number of Explicit memory blocks in the Explicit heap, and then returns the number in the int type.

toString

public java.lang.String toString()

Returns the string expression of the object. This method invokes this.getName(), and then returns the results.

Specified by:

toString in class MemoryArea

Returns:

This method returns the reference to the String type object that indicates the string expression of the object.