com.opencloud.slee.resources.cgin

Class AbstractLazyEncodedDataObject<T>

java.lang.Object

com.opencloud.util.AbstractDataObject

com.opencloud.util.AbstractFieldsObject

AbstractEncodedDataObject<T>

AbstractLazyEncodedDataObject<T>

All Implemented Interfaces:

DataObject, Serializable

Direct Known Subclasses:

AbstractLazyEncodedByteArray, AbstractLazyEncodedNamedInteger

public abstract class AbstractLazyEncodedDataObject<T>
extends AbstractEncodedDataObject<T>

Class AbstractLazyEncodedDataObject represents a DataObject in which the state is represented in an encoded form or a decoded form, with conversions between the two forms done lazily (when needed). Having a decoded representation of the state is convenient if the positions of fields in the encoded representation can vary depending on the values of other fields that might not have been supplied yet. For example, the presence/absence of optional fields, and the lengths of variable-length fields, can both affect the positions of later fields. Once an object has been marked read-only, both encoded and decoded forms can co-exist.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	isDecoded Whether the state is in the decoded form.

Fields inherited from class AbstractEncodedDataObject

encoded

Fields inherited from class com.opencloud.util.AbstractFieldsObject

FIELD_ABSENT, FIELD_UNINITIALISED

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractLazyEncodedDataObject() Constructs a new AbstractLazyEncodedDataObject.
protected	AbstractLazyEncodedDataObject(byte[] data, int start, int len) Constructs a new AbstractLazyEncodedDataObject from part of given network-encoded data.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	checkDecode() Ensures that the state is in the decoded form.
protected abstract void	checkFieldsSet() Checks that all mandatory fields are present.
protected void	checkModifyAndDecode() For use before setting a field of the decoded representation: checks that the object has not been marked read-only, and ensures that the state is in the decoded form.
protected abstract void	decode() Computes the decoded form of the state from the encoded form.
protected abstract void	encode() Computes the encoded form of the state from the decoded form.

Methods inherited from class com.opencloud.util.AbstractFieldsObject

equals, getFieldsMap, hashCode, toString

Methods inherited from class com.opencloud.util.AbstractDataObject

checkModify, clone, isReadOnly, setReadOnly

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

isDecoded

protected volatile boolean isDecoded

Whether the state is in the decoded form. (The state is in the encoded form if encoded != null.)

Constructor Detail

AbstractLazyEncodedDataObject

protected AbstractLazyEncodedDataObject()

Constructs a new AbstractLazyEncodedDataObject. The state is in the decoded form, despite none of the fields having been set yet, as there is no encoded form.

AbstractLazyEncodedDataObject

protected AbstractLazyEncodedDataObject(byte[] data,
                             int start,
                             int len)

Constructs a new AbstractLazyEncodedDataObject from part of given network-encoded data. The part starts at index start and is len bytes long. The state is in the encoded form: it is not decoded and might not be decodable.

Parameters:

data - network-encoded data

start - starting offset of network-encoded data

len - length of encoded data in bytes

Throws:

NullPointerException - if data is null

IllegalArgumentException - if len is negative

ArrayIndexOutOfBoundsException - if the part is not within the data

Method Detail

checkFieldsSet

protected abstract void checkFieldsSet()
                                throws EncodeException

Checks that all mandatory fields are present. Should be called immediately before all calls to encode().

Throws:

EncodeException - if any mandatory field is not present

encode

protected abstract void encode()
                        throws EncodeException

Computes the encoded form of the state from the decoded form. Should check that individual field values are within appropriate ranges, and different fields have mutually consistent values, but needn't repeat the checks done by checkFieldsSet(). The computed encoded form should equal that from which the decoded form could have been calculated using decode(), i.e. encode o decode = id.

Throws:

EncodeException - if encoding fails

decode

protected abstract void decode()
                        throws DecodeException

Computes the decoded form of the state from the encoded form. The computed decoded form should equal that from which the encoded form could have been calculated using encode(), i.e. decode o encode = id. If a field cannot be decoded without further information, such as a DigitCodec to be used for decoding a digit string, then the encoded form of that field should be copied and kept for decoding by that field's getter, which will be given the further information. The caller should set isDecoded to true.

Throws:

DecodeException - if decoding fails

checkDecode

protected void checkDecode()
                    throws DecodeException

Ensures that the state is in the decoded form.

Throws:

DecodeException - if decoding fails

checkModifyAndDecode

protected void checkModifyAndDecode()
                             throws IllegalStateException,
                                    DecodeException

For use before setting a field of the decoded representation: checks that the object has not been marked read-only, and ensures that the state is in the decoded form.

Throws:

IllegalStateException - if the object is readonly

DecodeException - if decoding fails