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Method (Java Debug Interface) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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Java Debug Interface
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com.sun.jdi
Interface Method

All Superinterfaces:
Accessible, Comparable<Method>, Locatable, Mirror, TypeComponent
public interface Method
extends TypeComponent, Locatable, Comparable<Method>

A static or instance method in the target VM. See TypeComponent for general information about Field and Method mirrors.

Since:
1.3
See Also:
ObjectReference, ReferenceType

Method Summary
 List<Location> allLineLocations()
          Returns a list containing a Location object for each executable source line in this method.
 List<Location> allLineLocations(String stratum, String sourceName)
          Returns a list containing a Location object for each executable source line in this method.
 List<LocalVariable> arguments()
          Returns a list containing each LocalVariable that is declared as an argument of this method.
 List<String> argumentTypeNames()
          Returns a list containing a text representation of the type of each formal parameter of this method.
 List<Type> argumentTypes()
          Returns a list containing the type of each formal parameter of this method.
 byte[] bytecodes()
          Returns an array containing the bytecodes for this method.
 boolean equals(Object obj)
          Compares the specified Object with this method for equality.
 int hashCode()
          Returns the hash code value for this Method.
 boolean isAbstract()
          Determine if this method is abstract.
 boolean isBridge()
          Determine if this method is a bridge method.
 boolean isConstructor()
          Determine if this method is a constructor.
 boolean isNative()
          Determine if this method is native.
 boolean isObsolete()
          Determine if this method is obsolete.
 boolean isStaticInitializer()
          Determine if this method is a static initializer.
 boolean isSynchronized()
          Determine if this method is synchronized.
 boolean isVarArgs()
          Determine if this method accepts a variable number of arguments.
 Location location()
          Returns the Location of this method, if there is executable code associated with it.
 Location locationOfCodeIndex(long codeIndex)
          Returns a Location for the given code index.
 List<Location> locationsOfLine(int lineNumber)
          Returns a List containing all Location objects that map to the given line number.
 List<Location> locationsOfLine(String stratum, String sourceName, int lineNumber)
          Returns a List containing all Location objects that map to the given line number and source name.
 Type returnType()
          Returns the return type, as specified in the declaration of this method.
 String returnTypeName()
          Returns a text representation of the return type, as specified in the declaration of this method.
 List<LocalVariable> variables()
          Returns a list containing each LocalVariable declared in this method.
 List<LocalVariable> variablesByName(String name)
          Returns a list containing each LocalVariable of a given name in this method.
 
Methods inherited from interface com.sun.jdi.TypeComponent
declaringType, genericSignature, isFinal, isStatic, isSynthetic, name, signature
 
Methods inherited from interface com.sun.jdi.Mirror
toString, virtualMachine
 
Methods inherited from interface com.sun.jdi.Accessible
isPackagePrivate, isPrivate, isProtected, isPublic, modifiers
 
Methods inherited from interface java.lang.Comparable
compareTo
 

Method Detail

returnTypeName

String returnTypeName()
Returns a text representation of the return type, as specified in the declaration of this method.

This type name is always available even if the type has not yet been created or loaded.

Returns:
a String containing the return type name.

returnType

Type returnType()
                throws ClassNotLoadedException
Returns the return type, as specified in the declaration of this method.

Note: if the return type of this method is a reference type (class, interface, or array) and it has not been created or loaded by the declaring type's class loader - that is, declaringType() .classLoader(), then ClassNotLoadedException will be thrown. Also, a reference type may have been loaded but not yet prepared, in which case the type will be returned but attempts to perform some operations on the returned type (e.g. fields()) will throw a ClassNotPreparedException. Use ReferenceType.isPrepared() to determine if a reference type is prepared.

Returns:
the return Type of this method.
Throws:
ClassNotLoadedException - if the type has not yet been created or loaded through the appropriate class loader.
See Also:
Type, Field.type() - for usage examples

argumentTypeNames

List<String> argumentTypeNames()
Returns a list containing a text representation of the type of each formal parameter of this method.

This list is always available even if the types have not yet been created or loaded.

Returns:
a List of String, one List element for each parameter of this method. Each element represents the type of a formal parameter as specified at compile-time. If the formal parameter was declared with an ellipsis, then it is represented as an array of the type before the ellipsis.

argumentTypes

List<Type> argumentTypes()
                         throws ClassNotLoadedException
Returns a list containing the type of each formal parameter of this method.

Note: if there is any parameter whose type is a reference type (class, interface, or array) and it has not been created or loaded by the declaring type's class loader - that is, declaringType() .classLoader(), then ClassNotLoadedException will be thrown. Also, a reference type may have been loaded but not yet prepared, in which case the list will be returned but attempts to perform some operations on the type (e.g. fields()) will throw a ClassNotPreparedException. Use ReferenceType.isPrepared() to determine if a reference type is prepared.

Returns:
return a List of Type, one List element for each parameter of this method. Each element represents the type of a formal parameter as specified at compile-time. If the formal parameter was declared with an ellipsis, then it is represented as an array of the type before the ellipsis.
Throws:
ClassNotLoadedException - if the type has not yet been loaded through the appropriate class loader.
See Also:
Type

isAbstract

boolean isAbstract()
Determine if this method is abstract.

Returns:
true if the method is declared abstract; false otherwise.

isSynchronized

boolean isSynchronized()
Determine if this method is synchronized.

Returns:
true if the method is declared synchronized; false otherwise.

isNative

boolean isNative()
Determine if this method is native.

Returns:
true if the method is declared native; false otherwise.

isVarArgs

boolean isVarArgs()
Determine if this method accepts a variable number of arguments.

Returns:
true if the method accepts a variable number of arguments, false otherwise.
Since:
1.5

isBridge

boolean isBridge()
Determine if this method is a bridge method. Bridge methods are defined in the "JavaTM Language Specification, 3rd Edition.

Returns:
true if the method is a bridge method, false otherwise.
Since:
1.5

isConstructor

boolean isConstructor()
Determine if this method is a constructor.

Returns:
true if the method is a constructor; false otherwise.

isStaticInitializer

boolean isStaticInitializer()
Determine if this method is a static initializer.

Returns:
true if the method is a static initializer; false otherwise.

isObsolete

boolean isObsolete()
Determine if this method is obsolete.

Returns:
true if this method has been made obsolete by a VirtualMachine.redefineClasses(java.util.Map) operation.
Since:
1.4

allLineLocations

List<Location> allLineLocations()
                                throws AbsentInformationException
Returns a list containing a Location object for each executable source line in this method.

This method is equivalent to allLineLocations(vm.getDefaultStratum(),null) - see allLineLocations(String,String) for more information.

Returns:
a List of all source line Location objects.
Throws:
AbsentInformationException - if there is no line number information for this (non-native, non-abstract) method.

allLineLocations

List<Location> allLineLocations(String stratum,
                                String sourceName)
                                throws AbsentInformationException
Returns a list containing a Location object for each executable source line in this method.

Each location maps a source line to a range of code indices. The beginning of the range can be determined through Location.codeIndex(). The returned list is ordered by code index (from low to high).

The returned list may contain multiple locations for a particular line number, if the compiler and/or VM has mapped that line to two or more disjoint code index ranges.

If the method is native or abstract, an empty list is returned.

Returned list is for the specified stratum (see Location for a description of strata).

Parameters:
stratum - The stratum to retrieve information from or null for the ReferenceType.defaultStratum()
sourceName - Return locations only within this source file or null to return locations.
Returns:
a List of all source line Location objects.
Throws:
AbsentInformationException - if there is no line number information for this (non-native, non-abstract) method. Or if sourceName is non-null and source name information is not present.
Since:
1.4

locationsOfLine

List<Location> locationsOfLine(int lineNumber)
                               throws AbsentInformationException
Returns a List containing all Location objects that map to the given line number.

This method is equivalent to locationsOfLine(vm.getDefaultStratum(), null, lineNumber) - see locationsOfLine(java.lang.String,java.lang.String,int) for more information.

Parameters:
lineNumber - the line number
Returns:
a List of Location objects that map to the given line number.
Throws:
AbsentInformationException - if there is no line number information for this method.

locationsOfLine

List<Location> locationsOfLine(String stratum,
                               String sourceName,
                               int lineNumber)
                               throws AbsentInformationException
Returns a List containing all Location objects that map to the given line number and source name.

Returns a list containing each Location that maps to the given line. The returned list will contain a location for each disjoint range of code indices that have been assigned to the given line by the compiler and/or VM. Each returned location corresponds to the beginning of this range. An empty list will be returned if there is no executable code at the specified line number; specifically, native and abstract methods will always return an empty list.

Returned list is for the specified stratum (see Location for a description of strata).

Parameters:
stratum - the stratum to use for comparing line number and source name, or null to use the default stratum
sourceName - the source name containing the line number, or null to match all source names
lineNumber - the line number
Returns:
a List of Location objects that map to the given line number.
Throws:
AbsentInformationException - if there is no line number information for this method. Or if sourceName is non-null and source name information is not present.
Since:
1.4

locationOfCodeIndex

Location locationOfCodeIndex(long codeIndex)
Returns a Location for the given code index.

Returns:
the Location corresponding to the given code index or null if the specified code index is not a valid code index for this method (native and abstract methods will always return null).

variables

List<LocalVariable> variables()
                              throws AbsentInformationException
Returns a list containing each LocalVariable declared in this method. The list includes any variable declared in any scope within the method. It may contain multiple variables of the same name declared within disjoint scopes. Arguments are considered local variables and will be present in the returned list. If local variable information is not available, values of actual arguments to method invocations can be obtained by using the method StackFrame.getArgumentValues()

Returns:
the list of LocalVariable objects which mirror local variables declared in this method in the target VM. If there are no local variables, a zero-length list is returned.
Throws:
AbsentInformationException - if there is no variable information for this method. Generally, local variable information is not available for native or abstract methods (that is, their argument name information is not available), thus they will throw this exception.

variablesByName

List<LocalVariable> variablesByName(String name)
                                    throws AbsentInformationException
Returns a list containing each LocalVariable of a given name in this method. Multiple variables can be returned if the same variable name is used in disjoint scopes within the method.

Returns:
the list of LocalVariable objects of the given name. If there are no matching local variables, a zero-length list is returned.
Throws:
AbsentInformationException - if there is no variable information for this method. Generally, local variable information is not available for native or abstract methods (that is, their argument name information is not available), thus they will throw this exception.

arguments

List<LocalVariable> arguments()
                              throws AbsentInformationException
Returns a list containing each LocalVariable that is declared as an argument of this method. If local variable information is not available, values of actual arguments to method invocations can be obtained by using the method StackFrame.getArgumentValues()

Returns:
the list of LocalVariable arguments. If there are no arguments, a zero-length list is returned.
Throws:
AbsentInformationException - if there is no variable information for this method. Generally, local variable information is not available for native or abstract methods (that is, their argument name information is not available), thus they will throw this exception.

bytecodes

byte[] bytecodes()
Returns an array containing the bytecodes for this method.

Not all target virtual machines support this operation. Use VirtualMachine.canGetBytecodes() to determine if the operation is supported.

Returns:
the array of bytecodes; abstract and native methods will return a zero-length array.
Throws:
UnsupportedOperationException - if the target virtual machine does not support the retrieval of bytecodes.

location

Location location()
Returns the Location of this method, if there is executable code associated with it.

Specified by:
location in interface Locatable
Returns:
the Location of this mirror, or null if this is an abstract method; native methods will return a Location object whose codeIndex is -1.

equals

boolean equals(Object obj)
Compares the specified Object with this method for equality.

Overrides:
equals in class Object
Returns:
true if the Object is a method and if both mirror the same method (declared in the same class or interface, in the same VM).

hashCode

int hashCode()
Returns the hash code value for this Method.

Overrides:
hashCode in class Object
Returns:
the integer hash code
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Java Debug Interface
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