| com.sleepycat.persist.impl.Accessor
All known Subclasses: com.sleepycat.persist.impl.RawAccessor, com.sleepycat.persist.impl.EnhancedAccessor, com.sleepycat.persist.impl.ReflectionAccessor,
| Accessor | | interface Accessor (Code) | | Field binding operations implemented via reflection (ReflectionAccessor) or
bytecode enhancement (EnhancedAccessor).
Normally we read the set of all secondary key fields first and then the
set of all non-key fields, reading each set in order of field name. But
when reading an old format record we must account for the following
class evolution conversions:
- Convert a field: pass value thru converter
- Widen a field type: pass value thru widener
- Add a field: don't read the new field
- Delete a field: skip the deleted field
- Rename a field: read field in a different order
To support these operations, the methods for reading fields allow reading
specific ranges of fields as well as all fields. For example, all fields
up to a deleted field could be read, and then all fields from the following
field onward.
author:
Mark Hayes |
| Field Summary | |
| final int | MAX_FIELD_NUM
A large field value to use instead of Integer.MAX_VALUE, to work around
Java JIT compiler bug when doing an (X <= Integer.MAX_VALUE) as would be
done in readXxxKeyFields methods. |
| Method Summary | |
| Object | getField(Object o, int field, int superLevel, boolean isSecField)
Returns the value of a given field, representing primitives as primitive
wrapper objects.
Parameters:
o - is the object containing the key field.
Parameters:
field - is the field index.
Parameters:
superLevel - is a positive number to identify the field of theclass that is the Nth super instance; or zero to identify the field inthis class.
Parameters:
isSecField - is true for a secondary key field or false for anon-key field. | | boolean | isPriKeyFieldNullOrZero(Object o)
Returns whether the primary key field is null (for a reference type) or
zero (for a primitive integer type). | | Object | newArray(int len)
Creates a new one dimensional array of the given length, having the
target class as its component type.
Using a special method for a one dimensional array, which can be
implemented by bytecode generation, is a compromise. | | Object | newInstance()
Creates a new instance of the target class using its default
constructor. | | void | readNonKeyFields(Object o, EntityInput input, int startField, int endField, int superLevel)
Reads a range of non-key field values from the given EntityInput,
reading fields in super classes first and in name order within class.
To read all fields, pass -1 for superLevel, zero for startField and
MAX_FIELD_NUM for endField. | | void | readPriKeyField(Object o, EntityInput input)
Reads the primary key field value from the given EntityInput. | | void | readSecKeyFields(Object o, EntityInput input, int startField, int endField, int superLevel)
Reads a range of secondary key field values from the given EntityInput,
reading fields in super classes first and in name order within class.
If the primary key has a reference type, this method must call
EntityInput.registerPriKeyObject before reading any other fields.
To read all fields, pass -1 for superLevel, zero for startField and
MAX_FIELD_NUM for endField. | | void | setField(Object o, int field, int superLevel, boolean isSecField, Object value)
Changes the value of a given field, representing primitives as primitive
wrapper objects. | | void | writeNonKeyFields(Object o, EntityOutput output)
Writes all non-key field values to the given EntityOutput, writing
fields in super classes first and in name order within class. | | void | writePriKeyField(Object o, EntityOutput output)
Writes the primary key field value to the given EntityOutput. | | void | writeSecKeyFields(Object o, EntityOutput output)
Writes all secondary key field values to the given EntityOutput,
writing fields in super classes first and in name order within class. |
| MAX_FIELD_NUM | | final int MAX_FIELD_NUM(Code) | | A large field value to use instead of Integer.MAX_VALUE, to work around
Java JIT compiler bug when doing an (X <= Integer.MAX_VALUE) as would be
done in readXxxKeyFields methods.
|
| getField | | Object getField(Object o, int field, int superLevel, boolean isSecField)(Code) | | Returns the value of a given field, representing primitives as primitive
wrapper objects.
Parameters:
o - is the object containing the key field.
Parameters:
field - is the field index.
Parameters:
superLevel - is a positive number to identify the field of theclass that is the Nth super instance; or zero to identify the field inthis class.
Parameters:
isSecField - is true for a secondary key field or false for anon-key field. the current field value, or null for a reference type fieldthat is null. |
| isPriKeyFieldNullOrZero | | boolean isPriKeyFieldNullOrZero(Object o)(Code) | | Returns whether the primary key field is null (for a reference type) or
zero (for a primitive integer type). Null and zero are used as an
indication that the key should be assigned from a sequence.
|
| newArray | | Object newArray(int len)(Code) | | Creates a new one dimensional array of the given length, having the
target class as its component type.
Using a special method for a one dimensional array, which can be
implemented by bytecode generation, is a compromise. We use reflection
to create multidimensional arrays. We could in the future generate code
to create arrays as they are encountered, if there is a need to avoid
reflection for multidimensional arrays.
|
| newInstance | | Object newInstance()(Code) | | Creates a new instance of the target class using its default
constructor.
|
| readNonKeyFields | | void readNonKeyFields(Object o, EntityInput input, int startField, int endField, int superLevel)(Code) | | Reads a range of non-key field values from the given EntityInput,
reading fields in super classes first and in name order within class.
To read all fields, pass -1 for superLevel, zero for startField and
MAX_FIELD_NUM for endField. Fields from super classes are read
first.
To read a specific range of fields, pass a non-negative number for
superLevel and the specific indices of the field range to be read in the
class at that level.
Parameters:
o - is the object whose non-key fields are to be read.
Parameters:
input - the input data to read from.
Parameters:
startField - the starting field index in the range of fields toread. To read all fields, the startField should be zero.
Parameters:
endField - the ending field index in the range of fields to read.To read all fields, the endField should be MAX_FIELD_NUM.
Parameters:
superLevel - is a non-negative number to read the fields of theclass that is the Nth super instance; or a negative number to readfields in all classes. |
| readPriKeyField | | void readPriKeyField(Object o, EntityInput input)(Code) | | Reads the primary key field value from the given EntityInput.
To read a primary key with a reference type, this method must call
EntityInput.readKeyObject.
Parameters:
o - is the object whose primary key field is to be read.
Parameters:
input - the input data to read from. |
| readSecKeyFields | | void readSecKeyFields(Object o, EntityInput input, int startField, int endField, int superLevel)(Code) | | Reads a range of secondary key field values from the given EntityInput,
reading fields in super classes first and in name order within class.
If the primary key has a reference type, this method must call
EntityInput.registerPriKeyObject before reading any other fields.
To read all fields, pass -1 for superLevel, zero for startField and
MAX_FIELD_NUM for endField. Fields from super classes are read
first.
To read a specific range of fields, pass a non-negative number for
superLevel and the specific indices of the field range to be read in the
class at that level.
Parameters:
o - is the object whose secondary key fields are to be read.
Parameters:
input - the input data to read from.
Parameters:
startField - the starting field index in the range of fields toread. To read all fields, the startField should be zero.
Parameters:
endField - the ending field index in the range of fields to read.To read all fields, the endField should be MAX_FIELD_NUM.
Parameters:
superLevel - is a non-negative number to read the fields of theclass that is the Nth super instance; or a negative number to readfields in all classes. |
| setField | | void setField(Object o, int field, int superLevel, boolean isSecField, Object value)(Code) | | Changes the value of a given field, representing primitives as primitive
wrapper objects.
Parameters:
o - is the object containing the key field.
Parameters:
field - is the field index.
Parameters:
superLevel - is a positive number to identify the field of theclass that is the Nth super instance; or zero to identify the field inthis class.
Parameters:
isSecField - is true for a secondary key field or false for anon-key field.
Parameters:
value - is the new value of the field, or null to set a referencetype field to null. |
| writeNonKeyFields | | void writeNonKeyFields(Object o, EntityOutput output)(Code) | | Writes all non-key field values to the given EntityOutput, writing
fields in super classes first and in name order within class.
Parameters:
o - is the object whose non-key fields are to be written.
Parameters:
output - the output data to write to. |
| writePriKeyField | | void writePriKeyField(Object o, EntityOutput output)(Code) | | Writes the primary key field value to the given EntityOutput.
To write a primary key with a reference type, this method must call
EntityOutput.writeKeyObject.
Parameters:
o - is the object whose primary key field is to be written.
Parameters:
output - the output data to write to. |
| writeSecKeyFields | | void writeSecKeyFields(Object o, EntityOutput output)(Code) | | Writes all secondary key field values to the given EntityOutput,
writing fields in super classes first and in name order within class.
Parameters:
o - is the object whose secondary key fields are to be written.If the primary key has a reference type, this method must callEntityOutput.registerPriKeyObject before writing any other fields.
Parameters:
output - the output data to write to. |
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