java.lang.Object
- org.apache.derby.iapi.types.DataType
- - org.apache.derby.impl.store.access.heap.HeapRowLocation

All Implemented Interfaces:: java.io.Externalizable, java.io.Serializable, java.lang.Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, Orderable, RefDataValue, RowLocation

public class HeapRowLocation
extends DataType
implements RowLocation, RefDataValue

A heap row location represents the location of a row in the heap.

It is implementad as a wrapper around a raw store record handle.

See Also:: Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`private static int`	`BASE_MEMORY_USAGE`
`private long`	`pageno`	The HeapRowLocation simply maintains a raw store record handle.
`private int`	`recid`
`private static int`	`RECORD_HANDLE_MEMORY_USAGE`
`private RecordHandle`	`rh`

Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
UNKNOWN_LOGICAL_LENGTH

Fields inherited from interface org.apache.derby.iapi.types.Orderable
ORDER_OP_EQUALS, ORDER_OP_GREATEROREQUALS, ORDER_OP_GREATERTHAN, ORDER_OP_LESSOREQUALS, ORDER_OP_LESSTHAN

Constructor Summary

Constructors
Modifier Constructor Description

HeapRowLocation()

(package private) HeapRowLocation(RecordHandle rh)

private HeapRowLocation(HeapRowLocation other)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`DataValueDescriptor`	`cloneValue(boolean forceMaterialization)`	Clone this DataValueDescriptor.
`boolean`	`compare(int op, DataValueDescriptor other, boolean orderedNulls, boolean unknownRV)`	Compare this Orderable with a given Orderable for the purpose of qualification and sorting.
`int`	`compare(DataValueDescriptor other)`	Compare this Orderable with a given Orderable for the purpose of index positioning.
`boolean`	`equals(java.lang.Object ref)`	Implement value equality.
`int`	`estimateMemoryUsage()`	Estimate the memory usage in bytes of the data value and the overhead of the class.
`int`	`getLength()`	Gets the length of the data value.
`DataValueDescriptor`	`getNewNull()`	Get a new null value of the same type as this data value.
`java.lang.Object`	`getObject()`	Gets the value in the data value descriptor as a int.
`RecordHandle`	`getRecordHandle(ContainerHandle ch)`
`java.lang.String`	`getString()`	Gets the value in the data value descriptor as a String.
`int`	`getTypeFormatId()`	Return my format identifier.
`java.lang.String`	`getTypeName()`	Get the SQL name of the datatype
`int`	`hashCode()`	Return a hashcode based on value.
`boolean`	`isNull()`	Return whether the value is null or not.
`void`	`readExternal(java.io.ObjectInput in)`
`void`	`readExternalFromArray(ArrayInputStream in)`	Read the DataValueDescriptor from the stream.
`DataValueDescriptor`	`recycle()`	Recycle this HeapRowLocation object.
`void`	`restoreToNull()`	Restore this object to its (SQL)null value.
`(package private) void`	`setFrom(RecordHandle rh)`
`protected void`	`setFrom(DataValueDescriptor theValue)`	Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
`void`	`setValue(RowLocation rowLocation)`	Set the value of this RefDataValue.
`void`	`setValueFromResultSet(java.sql.ResultSet resultSet, int colNumber, boolean isNullable)`	Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
`java.lang.String`	`toString()`
`void`	`writeExternal(java.io.ObjectOutput out)`

Methods inherited from class org.apache.derby.iapi.types.DataType
checkHostVariable, cloneHolder, coalesce, compare, compare, compareTo, dataTypeConversion, equals, flip, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, typePrecedence, typeToBigDecimal

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
checkHostVariable, cloneHolder, coalesce, compare, compare, equals, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, typePrecedence, typeToBigDecimal

- Field Detail
  - pageno
```
private long pageno
```
    The HeapRowLocation simply maintains a raw store record handle.
  - recid
```
private int recid
```
  - rh
```
private RecordHandle rh
```
  - BASE_MEMORY_USAGE
```
private static final int BASE_MEMORY_USAGE
```
  - RECORD_HANDLE_MEMORY_USAGE
```
private static final int RECORD_HANDLE_MEMORY_USAGE
```
- Constructor Detail
  - HeapRowLocation
```
HeapRowLocation(RecordHandle rh)
```
  - HeapRowLocation
```
public HeapRowLocation()
```
  - HeapRowLocation
```
private HeapRowLocation(HeapRowLocation other)
```
- Method Detail
  - estimateMemoryUsage
```
public int estimateMemoryUsage()
```
    Description copied from interface: DataValueDescriptor
    
    Estimate the memory usage in bytes of the data value and the overhead of the class.
    
    Specified by:
    
    estimateMemoryUsage in interface DataValueDescriptor
    
    Returns:
    
    the estimated memory usage
  - getTypeName
```
public java.lang.String getTypeName()
```
    Description copied from interface: DataValueDescriptor
    
    Get the SQL name of the datatype
    
    Specified by:
    
    getTypeName in interface DataValueDescriptor
    
    Returns:
    
    The SQL name of the datatype
  - setValueFromResultSet
```
public void setValueFromResultSet(java.sql.ResultSet resultSet,
                                  int colNumber,
                                  boolean isNullable)
```
    Description copied from interface: DataValueDescriptor
    
    Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
    
    Specified by:
    
    setValueFromResultSet in interface DataValueDescriptor
    
    Parameters:
    
    resultSet - The specified ResultSet.
    
    colNumber - The 1-based column # into the resultSet.
    
    isNullable - Whether or not the column is nullable (No need to call wasNull() if not)
  - getNewNull
```
public DataValueDescriptor getNewNull()
```
    Description copied from interface: DataValueDescriptor
    
    Get a new null value of the same type as this data value.
    
    Specified by:
    
    getNewNull in interface DataValueDescriptor
  - getObject
```
public java.lang.Object getObject()
```
    Description copied from class: DataType
    
    Gets the value in the data value descriptor as a int. Throws an exception if the data value is not receivable as a int.
    
    Specified by:
    
    getObject in interface DataValueDescriptor
    
    Overrides:
    
    getObject in class DataType
    
    Returns:
    
    The data value as a int.
  - cloneValue
```
public DataValueDescriptor cloneValue(boolean forceMaterialization)
```
    Description copied from interface: DataValueDescriptor
    
    Clone this DataValueDescriptor. Results in a new object that has the same value as this but can be modified independently.
    Even though the objects can be modified independently regardless of the value of forceMaterialization, both the clone and the original may be dependent on the store state if forceMaterialization is set to false. An example is if you need to access the value you just read using cloneValue after the current transaction has ended, or after the source result set has been closed.
    
    Specified by:
    
    cloneValue in interface DataValueDescriptor
    
    Parameters:
    
    forceMaterialization - any streams representing the data value will be materialized if true, the data value will be kept as a stream if possible if false
    
    Returns:
    
    A clone of the DataValueDescriptor with the same initial value as this.
  - recycle
```
public DataValueDescriptor recycle()
```
    Recycle this HeapRowLocation object.
    
    Specified by:
    
    recycle in interface DataValueDescriptor
    
    Overrides:
    
    recycle in class DataType
    
    Returns:
    
    this object reset to its initial state
  - getLength
```
public int getLength()
```
    Description copied from interface: DataValueDescriptor
    
    Gets the length of the data value. The meaning of this is implementation-dependent. For string types, it is the number of characters in the string. For numeric types, it is the number of bytes used to store the number. This is the actual length of this value, not the length of the type it was defined as. For example, a VARCHAR value may be shorter than the declared VARCHAR (maximum) length.
    
    Specified by:
    
    getLength in interface DataValueDescriptor
    
    Returns:
    
    The length of the data value
  - getString
```
public java.lang.String getString()
```
    Description copied from interface: DataValueDescriptor
    
    Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.
    
    Specified by:
    
    getString in interface DataValueDescriptor
    
    Returns:
    
    The data value as a String.
  - compare
```
public boolean compare(int op,
                       DataValueDescriptor other,
                       boolean orderedNulls,
                       boolean unknownRV)
```
    Description copied from interface: DataValueDescriptor
    
    Compare this Orderable with a given Orderable for the purpose of qualification and sorting. The caller gets to determine how nulls should be treated - they can either be ordered values or unknown values.
    
    Specified by:
    
    compare in interface DataValueDescriptor
    
    Overrides:
    
    compare in class DataType
    
    Parameters:
    
    op - Orderable.ORDER_OP_EQUALS means do an = comparison. Orderable.ORDER_OP_LESSTHAN means compare this < other. Orderable.ORDER_OP_LESSOREQUALS means compare this <= other.
    
    other - The DataValueDescriptor to compare this one to.
    
    orderedNulls - True means to treat nulls as ordered values, that is, treat SQL null as equal to null, and less than all other values. False means to treat nulls as unknown values, that is, the result of any comparison with a null is the UNKNOWN truth value.
    
    unknownRV - The return value to use if the result of the comparison is the UNKNOWN truth value. In other words, if orderedNulls is false, and a null is involved in the comparison, return unknownRV. This parameter is not used orderedNulls is true.
    
    Returns:
    
    true if the comparison is true (duh!)
  - compare
```
public int compare(DataValueDescriptor other)
```
    Description copied from interface: DataValueDescriptor
    
    Compare this Orderable with a given Orderable for the purpose of index positioning. This method treats nulls as ordered values - that is, it treats SQL null as equal to null and greater than all other values.
    
    Specified by:
    
    compare in interface DataValueDescriptor
    
    Parameters:
    
    other - The Orderable to compare this one to.
    
    Returns:
    
    <0 - this Orderable is less than other. 0 - this Orderable equals other. >0 - this Orderable is greater than other. The code should not explicitly look for -1, or 1.
  - setValue
```
public void setValue(RowLocation rowLocation)
```
    Description copied from interface: RefDataValue
    
    Set the value of this RefDataValue.
    
    Specified by:
    
    setValue in interface RefDataValue
    
    Parameters:
    
    rowLocation - Contains the boolean value to set this RefDataValue to. Null means set this RefDataValue to null.
  - getRecordHandle
```
public RecordHandle getRecordHandle(ContainerHandle ch)
                             throws StandardException
```
    Throws:
    
    StandardException
  - setFrom
```
void setFrom(RecordHandle rh)
```
  - getTypeFormatId
```
public int getTypeFormatId()
```
    Return my format identifier.
    
    Specified by:
    
    getTypeFormatId in interface TypedFormat
    
    Returns:
    
    The identifier. (A UUID stuffed in an array of 16 bytes).
    
    See Also:
    
    TypedFormat.getTypeFormatId()
  - isNull
```
public boolean isNull()
```
    Description copied from interface: Storable
    
    Return whether the value is null or not.
    
    Specified by:
    
    isNull in interface Storable
    
    Returns:
    
    true if the value is null and false otherwise.
  - writeExternal
```
public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
```
    Specified by:
    
    writeExternal in interface java.io.Externalizable
    
    Throws:
    
    java.io.IOException
  - readExternal
```
public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException
```
    Specified by:
    
    readExternal in interface java.io.Externalizable
    
    Throws:
    
    java.lang.ClassNotFoundException - A class needed to read the stored form of this object could not be found.
    
    java.io.IOException
    
    See Also:
    
    Externalizable.readExternal(java.io.ObjectInput)
  - readExternalFromArray
```
public void readExternalFromArray(ArrayInputStream in)
                           throws java.io.IOException,
                                  java.lang.ClassNotFoundException
```
    Description copied from class: DataType
    
    Read the DataValueDescriptor from the stream. The default implementation calls readExternal(), which accesses the ArrayInputStream as a generic stream. If sub-classes can implement it more efficiently by accessing the array, they should override this method.
    
    Specified by:
    
    readExternalFromArray in interface DataValueDescriptor
    
    Overrides:
    
    readExternalFromArray in class DataType
    
    Parameters:
    
    in - The array stream positioned at the beginning of the byte stream to read from.
    
    Throws:
    
    java.io.IOException - Usual error is if you try to read past limit on the stream.
    
    java.lang.ClassNotFoundException - If a necessary class can not be found while reading the object from the stream.
    
    See Also:
    
    DataValueDescriptor.readExternalFromArray(org.apache.derby.iapi.services.io.ArrayInputStream), Externalizable.readExternal(java.io.ObjectInput)
  - restoreToNull
```
public void restoreToNull()
```
    Description copied from interface: Storable
    
    Restore this object to its (SQL)null value.
    
    Specified by:
    
    restoreToNull in interface Storable
  - setFrom
```
protected void setFrom(DataValueDescriptor theValue)
```
    Description copied from class: DataType
    
    Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
    
    Overrides:
    
    setFrom in class DataType
    
    Parameters:
    
    theValue - The DataValueDescriptor that holds the value to which we want to set this DataValueDescriptor's value.
  - equals
```
public boolean equals(java.lang.Object ref)
```
    Implement value equality.
    MT - Thread safe
    
    Overrides:
    
    equals in class DataType
  - hashCode
```
public int hashCode()
```
    Return a hashcode based on value.
    MT - thread safe
    
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Format ID	ACCESS_HEAP_ROW_LOCATION_V1_ID
Purpose
Object used to store the location of a row within a Heap table. One of these is stored in every row of a btree secondary index built on a heap base table.
Upgrade
The type of the btree determines the type of rowlocation stored. In current btree implementations only one type of rowlocation can be stored per tree, and it's type is stored in the format id array stored in the Conglomerate object.
Disk Layout	page number(CompressedNumber.writeLong()) record id(CompressedNumber.writeInt())

Modifier	Constructor	Description
	`HeapRowLocation()`
`(package private)`	`HeapRowLocation(RecordHandle rh)`
`private`	`HeapRowLocation(HeapRowLocation other)`

Class HeapRowLocation

Field Summary

Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor

Fields inherited from interface org.apache.derby.iapi.types.Orderable

Constructor Summary

Method Summary

Methods inherited from class org.apache.derby.iapi.types.DataType

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor

Field Detail

pageno

recid

rh

BASE_MEMORY_USAGE

RECORD_HANDLE_MEMORY_USAGE

Constructor Detail

HeapRowLocation

HeapRowLocation

HeapRowLocation

Method Detail

estimateMemoryUsage

getTypeName

setValueFromResultSet

getNewNull

getObject

cloneValue

recycle

getLength

getString

compare

compare

setValue

getRecordHandle

setFrom

getTypeFormatId

isNull

writeExternal

readExternal

readExternalFromArray

restoreToNull

setFrom

equals

hashCode

toString