messif.objects.util
Class StreamsMetaObjectMapIterator

java.lang.Object
  messif.objects.util.AbstractObjectIterator<E>
      messif.objects.util.AbstractStreamObjectIterator<MetaObjectMap>
          messif.objects.util.StreamsMetaObjectMapIterator

All Implemented Interfaces:

java.io.Closeable, java.util.Iterator<MetaObjectMap>, ObjectProvider<MetaObjectMap>

public class StreamsMetaObjectMapIterator
extends AbstractStreamObjectIterator<MetaObjectMap>

This class is to contruct MetaObjects from several simultaneously opened files (subObjectIterators). The iterator expects the files to store corresponding objects always in the same order alowing gaps - locators are always checked for actually "first" objects in the opened subObjectIterators. If more than one locator is at the top of the subObjectIterators, the majority of them is expected to be the right locator to be created at the moment and the other are not created.

Field Summary

protected MetaObjectMap	currentObject Instance of the current object
protected MetaObjectMap	nextObject Instance of a next object.
protected boolean	readingStarted Flag saying whether we have already started reading from the files or not yet.
protected java.util.Map<java.lang.String,StreamGenericAbstractObjectIterator>	subObjectIterators Particular iterators

Constructor Summary

StreamsMetaObjectMapIterator()
The empty constructor.

Method Summary

<T extends LocalAbstractObject> void	addObjectStream(java.lang.String name, java.lang.Class<? extends T> objClass, java.lang.String fileName) Add new object iterator given a name to be generated for this object in the MetaObjectMap.
void	addObjectStream(java.lang.String name, StreamGenericAbstractObjectIterator<? extends LocalAbstractObject> iterator) Add new object iterator given a name to be generated for this object in the MetaObjectMap.
void	close()
MetaObjectMap	getCurrentObject() Returns an object returned by the last call to Iterator.next().
boolean	hasNext()
MetaObjectMap	next()
void	remove()
void	reset() Reset the associated stream and restarts the iteration from beginning.
void	setConstructorParameter(int index, java.lang.Object paramValue) Sets the value of this stream's object constructor argument.
protected void	setNextObject() Internal method to read objects from the strems and construct new metaobject and set the new object to nextObject.
void	startReadingObjects() This method is internaly used to mark that the reading from the subObjectIterators started.

Methods inherited from class messif.objects.util.AbstractObjectIterator

getCurrentObjectID, getMatchingObjects, getMatchingObjects, getMatchingObjects, getMatchingObjects, getObjectByAnyLocator, getObjectByData, getObjectByID, getObjectByLocator, getObjectByPosition, getRandomObject, getRandomObjects, nextObjectID, provideObjects

Methods inherited from class java.lang.Object

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

Field Detail

subObjectIterators

protected java.util.Map<java.lang.String,StreamGenericAbstractObjectIterator> subObjectIterators

Particular iterators

nextObject

protected MetaObjectMap nextObject

Instance of a next object. This is needed for implementing reading objects from a stream

currentObject

protected MetaObjectMap currentObject

Instance of the current object

readingStarted

protected boolean readingStarted

Flag saying whether we have already started reading from the files or not yet.

Constructor Detail

StreamsMetaObjectMapIterator

public StreamsMetaObjectMapIterator()

The empty constructor.

Method Detail

addObjectStream

public void addObjectStream(java.lang.String name,
                            StreamGenericAbstractObjectIterator<? extends LocalAbstractObject> iterator)
                     throws java.lang.IllegalStateException

Add new object iterator given a name to be generated for this object in the MetaObjectMap.

Parameters:

name - name to be generated for this object in the MetaObjectMap

iterator - object iterator

Throws:

java.lang.IllegalStateException - when trying to add a stream and reading from the other subObjectIterators already started

addObjectStream

public <T extends LocalAbstractObject> void addObjectStream(java.lang.String name,
                                                            java.lang.Class<? extends T> objClass,
                                                            java.lang.String fileName)
                     throws java.lang.IllegalArgumentException,
                            java.io.IOException

Add new object iterator given a name to be generated for this object in the MetaObjectMap.

Type Parameters:

T - the type of the objects that are created from the file

Parameters:

name - name to be generated for this object in the MetaObjectMap

objClass - the type of the objects that are created from the file

fileName - file where the objects are stored

Throws:

java.lang.IllegalArgumentException - if the provided class does not have a proper "stream" constructor

java.io.IOException - if there was an error opening the file

getCurrentObject

public MetaObjectMap getCurrentObject()
                               throws java.util.NoSuchElementException

Description copied from class: AbstractObjectIterator

Returns an object returned by the last call to Iterator.next().

Specified by:

getCurrentObject in class AbstractObjectIterator<MetaObjectMap>

Returns:

an object returned by the last call to Iterator.next()

Throws:

java.util.NoSuchElementException - if Iterator.next() has not been called yet

hasNext

public boolean hasNext()

next

public MetaObjectMap next()

remove

public void remove()

close

public void close()
           throws java.io.IOException

Throws:

java.io.IOException

startReadingObjects

public void startReadingObjects()
                         throws java.lang.IllegalStateException,
                                java.io.IOException

This method is internaly used to mark that the reading from the subObjectIterators started.

Throws:

java.lang.IllegalStateException - if there is a gap in the files and there are two candidates for the next locator

java.io.IOException - error while closing stream iterator that reached its end

setNextObject

protected void setNextObject()
                      throws java.lang.IllegalStateException,
                             java.io.IOException

Internal method to read objects from the strems and construct new metaobject and set the new object to nextObject.

Throws:

java.lang.IllegalStateException - if there is a gap in the files and there are two candidates for the next locator

java.io.IOException - error while closing stream iterator that reached its end

setConstructorParameter

public void setConstructorParameter(int index,
                                    java.lang.Object paramValue)
                             throws java.lang.IndexOutOfBoundsException,
                                    java.lang.IllegalArgumentException,
                                    java.lang.InstantiationException

Description copied from class: AbstractStreamObjectIterator

Sets the value of this stream's object constructor argument. This method can be used to change object passed to constructorArgs.

Specified by:

setConstructorParameter in class AbstractStreamObjectIterator<MetaObjectMap>

Parameters:

index - the parameter index to change (zero-based)

paramValue - the changed value to pass to the constructor

Throws:

java.lang.IndexOutOfBoundsException - if the index parameter is out of bounds (zero parameter cannot be changed)

java.lang.IllegalArgumentException - when the passed object is incompatible with the constructor's parameter

java.lang.InstantiationException - if the value passed is string that is not convertible to the constructor class

reset

public void reset()
           throws java.io.IOException

Description copied from class: AbstractStreamObjectIterator

Reset the associated stream and restarts the iteration from beginning.

Specified by:

reset in class AbstractStreamObjectIterator<MetaObjectMap>

Throws:

java.io.IOException - if there was an I/O error re-opening the file