path: root/projects/net.wotonomy.datastore/src/main/java/net/wotonomy/datastore/DefaultDataView.java

/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2000 Michael Powers

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/

package net.wotonomy.datastore;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Observable;

public class DefaultDataView extends Observable implements DataView {
	protected DataSoup backingSoup;
	protected List objectList;
	protected List keyList;
	protected List addedObjectList;
	protected List removedObjectList;
	protected List addedKeyList;
	protected List removedKeyList;
	protected Collection updatedObjects;
	protected boolean fullyLoaded;

	DefaultDataView(DataSoup aSoup, Collection aKeyList) {
		backingSoup = aSoup;
		objectList = new ArrayList();
		keyList = new ArrayList();
		addedObjectList = new ArrayList();
		removedObjectList = new ArrayList();
		addedKeyList = new ArrayList();
		removedKeyList = new ArrayList();
		updatedObjects = new LinkedList();
		fullyLoaded = false;

		setKeyList(aKeyList);
	}

	void setKeyList(Collection aCollection) {
		fullyLoaded = false;
		addedObjectList.clear();
		removedObjectList.clear();
		addedKeyList.clear();
		removedKeyList.clear();
		updatedObjects.clear();
		keyList.clear();
		objectList.clear();
		if ((aCollection == null) || (aCollection.size() == 0)) {
			return;
		}
		keyList.addAll(aCollection);
		for (int i = 0; i < keyList.size(); i++) {
			objectList.add(null);
		}
	}

	public Object get(int i) {
		if (i > keyList.size())
			return null;

		Object o = objectList.get(i);
		if (o == null) {
			Object key = keyList.get(i);
			if (key == null)
				return null; // FIXME!!

			// NOTE: this is the gateway for getting object from the soup
			o = backingSoup.getObjectByKey((DataKey) key);

			objectList.set(i, o);
		}
		return o;
	}

	public int indexOf(Object o) {
		if (o == null)
			return -1;
		for (int i = 0; i < size(); i++) {
			if (o.equals(get(i))) {
				return i;
			}
		}
		return -1;
	}

	private int indexOfIdenticalObject(Object o) {
		if (o == null)
			return -1;
		for (int i = 0; i < size(); i++) {
			if (o == get(i)) {
				return i;
			}
		}
		return -1;
	}

	public int lastIndexOf(Object o) {
		if (o == null)
			return -1;
		int lastIndex = -1;
		for (int i = 0; i < size(); i++) {
			if (o.equals(get(i))) {
				lastIndex = i;
			}
		}
		return lastIndex;
	}

	protected void loadAllObjects() {
		if (fullyLoaded)
			return;
		for (int i = 0; i < keyList.size(); i++) {
			get(i);
		}
		fullyLoaded = true;
	}

	// convenience to return the first object, or null.
	public Object getObject() {
		return get(0);
	}

	// marked object as updated
	public void update(Object anObject) {
		if (contains(anObject)) {
			if (!addedObjectList.contains(anObject)) {
				updatedObjects.add(anObject);
			}
		}

		// notification
		setChanged();
		notifyObservers(anObject);
	}

	// DefaultDataViews know their parent soup to perform the query
	// and take the subset
	public DataView query(String aProperty, Object beginKey, Object endKey) {
		return this;
	}

	public boolean commit() {
		int index;
		Object o;
		DataKey key;
		for (int i = 0; i < addedObjectList.size(); i++) {
			o = addedObjectList.get(i);
			key = backingSoup.addObject(o);
			index = indexOfIdenticalObject(o);
			keyList.set(index, key);
		}
		addedObjectList.clear();
		addedKeyList.clear();
		for (int i = 0; i < removedObjectList.size(); i++) {
			backingSoup.removeObject((DataKey) removedKeyList.get(i));
		}
		removedObjectList.clear();
		removedKeyList.clear();

		int i;
		Iterator it = updatedObjects.iterator();
		while (it.hasNext()) {
			i = objectList.indexOf(it.next());
			backingSoup.updateObject((DataKey) keyList.get(i), objectList.get(i));
		}
		updatedObjects.clear();

		// notification
		setChanged();
		notifyObservers(this);

		return true;
	}

	public DataKey getKeyForObject(Object anObject) {
		int index = indexOfIdenticalObject(anObject);
		if (index == -1)
			return null;
		return (DataKey) keyList.get(index);
	}

	public Object getObjectForKey(DataKey aKey) {
		int index = keyList.indexOf(aKey);
		if (index == -1)
			return null;
		return get(index);
	}

	// interface Collection

	public int size() {
		return keyList.size();
	}

	public boolean isEmpty() {
		return keyList.isEmpty();
	}

	public void clear() {
		setKeyList(null);
	};

	public int hashCode() {
		return keyList.hashCode();
	};

	public boolean equals(Object o) {
		if (!(o instanceof DefaultDataView))
			return false;
		return keyList.equals(((DefaultDataView) o).keyList);
	}

	public boolean contains(Object o) {
		loadAllObjects();
		return objectList.contains(o);
	}

	public boolean containsAll(Collection c) {
		loadAllObjects();
		return objectList.containsAll(c);
	}

	public boolean add(Object o) {
		// if previously removed, restore to list
		if (removedObjectList.contains(o)) {
			int index = removedObjectList.indexOf(o);
			removedObjectList.remove(index);
			Object key = removedKeyList.remove(index);
			objectList.add(o);
			keyList.add(key);

			// notification
			setChanged();
			notifyObservers(o);
			return true;
		}

		// register and add to lists
		Object key = backingSoup.registerTemporaryObject(o);
		addedObjectList.add(o);
		addedKeyList.add(key);
		objectList.add(o);
		keyList.add(key);

		// notification
		setChanged();
		notifyObservers(o);
		return true;
	}

	public Object remove(int index) {
		Object result = get(index);
		if (remove(result)) {
			return result;
		}
		return null;
	}

	public boolean remove(Object o) {
		loadAllObjects();

		int index = objectList.indexOf(o);
		if (index == -1)
			return false;

		objectList.remove(index);
		Object key = keyList.remove(index);

		if (updatedObjects.contains(o)) {
			updatedObjects.remove(o);
		}

		// if not previously added, track removal
		if (!(removedObjectList.contains(o))) {
			removedObjectList.add(o);
			removedKeyList.add(key);
		}

		// notification
		setChanged();
		notifyObservers(o);

		return true;
	}

	/**
	 * Set completely replaces the object at the specified index with the specified
	 * object. The new object is not marked as inserted, and the old object is not
	 * marked as deleted: the new object will be stored in the soup with the same
	 * key. The old object is returned.
	 */
	public Object set(int index, Object element) {
		Object result = objectList.set(index, element);
		update(element);
		return result;
	}

	public void add(int index, Object o) {
		// if previously removed, restore to list
		if (removedObjectList.contains(o)) {
			int i = removedObjectList.indexOf(o);
			removedObjectList.remove(i);
			Object key = removedKeyList.remove(i);
			objectList.add(index, o);
			keyList.add(index, key);

			// notification
			setChanged();
			notifyObservers(o);
			return;
		}

		// register and add to lists
		Object key = backingSoup.registerTemporaryObject(o);
		addedObjectList.add(o);
		addedKeyList.add(key);
		objectList.add(index, o);
		keyList.add(index, key);

		// notification
		setChanged();
		notifyObservers(o);
	}

	public boolean addAll(Collection c) {
		boolean result = true;
		Iterator it = c.iterator();
		while (it.hasNext()) {
			result = result && add(it.next());
		}
		return result;
	}

	public boolean addAll(int index, Collection c) {
		int originalSize = size();
		boolean result = true;
		Iterator it = c.iterator();
		while (it.hasNext()) {
			add(index, it.next());
		}
		return (originalSize + c.size() == size());
	}

	public boolean removeAll(Collection c) {
		boolean result = true;
		Iterator it = c.iterator();
		while (it.hasNext()) {
			result = result && remove(it.next());
		}
		return result;
	}

	public boolean retainAll(Collection c) {
		removeAll(new ArrayList(objectList));
		return addAll(c);
	}

	public List subList(int fromIndex, int toIndex) {
		List result = new LinkedList();
		for (int i = fromIndex; i < toIndex; i++) {
			result.add(get(i));
		}
		return result;
	}

	public Iterator iterator() {
		loadAllObjects();
		return objectList.iterator();

		/*
		 * // uncomment to enable on-demand loading return new Iterator() { int index =
		 * 0; public boolean hasNext() { return ( index + 1 < keyList.size() ); } public
		 * Object next() { return get( index++ ); } public void remove() { Object o =
		 * get( index ); if ( o != null ) DefaultDataView.this.remove( o ); } };
		 */
	}

	public ListIterator listIterator() {
		return new DataViewIterator(this);
	}

	public ListIterator listIterator(int index) {
		return new DataViewIterator(this, index);
	}

	public Object[] toArray() {
		loadAllObjects();
		return objectList.toArray();
	}

	public java.lang.Object[] toArray(Object[] array) {
		loadAllObjects();
		return objectList.toArray(array);
	}

	protected class DataViewIterator implements ListIterator {
		DataView theView;
		int currentIndex;

		// TODO: should track current object in addition to index
		// to track external changes to the view. (or should be listener)
		Object currentObject;

		public DataViewIterator(DataView aView) {
			this(aView, 0);
		}

		public DataViewIterator(DataView aView, int index) {
			theView = aView;
			if (theView.size() > index) {
				currentIndex = index;
				currentObject = theView.get(currentIndex);
			} else {
				index = -1;
				currentObject = null;
			}
		}

		public void add(Object o) {
			currentIndex++;
			theView.add(currentIndex, o);
		}

		public boolean hasNext() {
			return (theView.size() > currentIndex + 1);
		}

		public boolean hasPrevious() {
			return (currentIndex > -1);
		}

		public Object next() {
			return theView.get(++currentIndex);
		}

		public int nextIndex() {
			return currentIndex + 1;
		}

		public Object previous() {
			return theView.get(currentIndex--);
		}

		public int previousIndex() {
			return currentIndex;
		}

		public void remove() {
			theView.remove(currentIndex--);
		}

		public void set(Object o) {
			theView.set(currentIndex, o);
		}

	}
}

/*
 * $Log$ Revision 1.2 2006/02/19 16:26:19 cgruber Move non-unit-test code to
 * tests project Fix up code to work with proper imports Fix maven dependencies.
 *
 * Revision 1.1 2006/02/16 13:18:56 cgruber Check in all sources in
 * eclipse-friendly maven-enabled packages.
 *
 * Revision 1.2 2001/02/15 21:12:41 mpowers Added accessors for key throughout
 * the api. This breaks compatibility. insertObject now returns the permanent
 * key for the newly created object. The old way returned a copy of the object
 * which was an additional read that was often ignored. Now you can read it only
 * if you need it. Furthermore, there was not other way of getting the permanent
 * key.
 *
 * Revision 1.1.1.1 2000/12/21 15:47:14 mpowers Contributing wotonomy.
 *
 * Revision 1.2 2000/12/20 16:25:36 michael Added log to all files.
 *
 *
 */