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Event-driven lists for dynamically filtered and sorted tables
/* Glazed Lists (c) 2003-2006 */
/* http://publicobject.com/glazedlists/ publicobject.com,*/
/* O'Dell Engineering Ltd.*/
package com.publicobject.amazonbrowser;
import ca.odell.glazedlists.EventList;
import ca.odell.glazedlists.ObservableElementList;
import ca.odell.glazedlists.BasicEventList;
import ca.odell.glazedlists.GlazedLists;
import javax.swing.event.SwingPropertyChangeSupport;
import java.beans.PropertyChangeListener;
import java.util.Date;
import java.util.Map;
import java.util.HashMap;
/**
* This class represents one of the levels of hierarchy that exist in the
* treetable of {@link Item} objects displayed in the AmazonBrowser. Each
* active TreeCriterion contributes to the overall TreeFormat. Available
* TreeCriterion objects include:
*
*
* - title
*
- audience rating
*
- price
*
- release date
*
*
* Note that users are expected to use the list of {@link @ALL_CRITERIA}, and
* are never supposed to create their own TreeCriterion objects.
*
* @author James Lemieux
*/
public abstract class TreeCriterion {
/** The List of all possible TreeCriterion objects. */
public static final EventList ALL_CRITERIA = new ObservableElementList(new BasicEventList(), GlazedLists.beanConnector(TreeCriterion.class));
static {
ALL_CRITERIA.add(new TitleCriterion());
ALL_CRITERIA.add(new AudienceRatingCriterion());
ALL_CRITERIA.add(new PriceCriterion());
ALL_CRITERIA.add(new ReleaseDateCriterion());
}
private final SwingPropertyChangeSupport support = new SwingPropertyChangeSupport(this);
/** A human readable name used to identify this TreeCriterion. */
private final String name;
/** A flag to indicate whether this TreeCriterion is active (and thus participating in the TreeFormat) or not. */
private boolean active;
/**
* A map from the title of each synthetic Item to the actual Item in the
* hierarchy. This acts as a cache to prevent building redundant synthetic
* hierarchy Items.
*/
private final Map syntheticItemCache = new HashMap();
private TreeCriterion(String name, boolean active) {
this.name = name;
this.active = active;
}
public void addPropertyChangeListener(PropertyChangeListener l) {
support.addPropertyChangeListener(l);
}
public void removePropertyChangeListener(PropertyChangeListener l) {
support.removePropertyChangeListener(l);
}
/**
* Returns a human readable name used to identify this TreeCriterion.
*/
public String getName() {
return name;
}
/**
* Returns true if this TreeCriterion is actively participating in
* the TreeFormat; false otherwise.
*/
public boolean isActive() {
return active;
}
/**
* Activates or deactivates this TreeCriterion from participating in the
* TreeFormat that governs what the tree hierarchies will resemble.
*/
public void setActive(boolean active) {
if (this.active == active) return;
this.active = active;
support.firePropertyChange("active", !active, active);
}
/**
* Implementations of this method should produce a new Item object whose
* title reflects some aspect of the given item and is
* appropriate for use as a tree hierarchy node value.
*/
public abstract Item getPathItem(Item item);
/**
* A convenience method to lazily populate the {@link #syntheticItemCache}
* and return a new Item with the given title.
*/
Item getOrCreateItem(String title) {
// check the cache
Item pathItem = syntheticItemCache.get(title);
// populate the cache if we missed
if (pathItem == null) {
pathItem = createSyntheticItem(title);
syntheticItemCache.put(title, pathItem);
}
return pathItem;
}
/**
* A convenience method to build and return a synthetic Item whose title is
* the given string.
*/
private static Item createSyntheticItem(String string) {
final ItemAttributes itemAttributes = new ItemAttributes();
itemAttributes.setTitle(string);
final Item item = new Item();
item.setItemAttributes(itemAttributes);
return item;
}
private static final class TitleCriterion extends TreeCriterion {
public TitleCriterion() {
super("Title", true);
}
/**
* Returns a synthetic Item whose title is the first Character
* of the title of the given item.
*/
@Override
public Item getPathItem(Item item) {
// extract the first char from the title of the item
final String title = item.getItemAttributes().getTitle();
return getOrCreateItem(title.length() == 0 ? "" : String.valueOf(title.charAt(0)));
}
}
private static final class AudienceRatingCriterion extends TreeCriterion {
public AudienceRatingCriterion() {
super("Audience Rating", true);
}
/**
* Returns a synthetic Item whose title is the name of the
* {@link AudienceRating}, if one exists, or "Unknown"
* if an {@link AudienceRating} does not exist.
*/
@Override
public Item getPathItem(Item item) {
final AudienceRating rating = item.getItemAttributes().getAudienceRating();
return getOrCreateItem(rating == null ? "Unknown" : rating.getDescription());
}
}
/**
* Returns a synthetic Item whose title is the name of the
* {@link AudienceRating}, if one exists, or "Unknown"
* if an {@link AudienceRating} does not exist.
*/
private static final class PriceCriterion extends TreeCriterion {
public PriceCriterion() {
super("Price", false);
}
@Override
public Item getPathItem(Item item) {
return getOrCreateItem("Not Yet Implemented");
}
}
private static final class ReleaseDateCriterion extends TreeCriterion {
public ReleaseDateCriterion() {
super("Release Date", true);
}
/**
* Returns a synthetic Item whose title is a String representing the
* decade of the release date of the item.
*/
@Override
public Item getPathItem(Item item) {
// extract the release year of the Item
final Date releaseDate = item.getItemAttributes().getReleaseDate();
if (releaseDate == null) {
return getOrCreateItem("Unknown");
} else {
// normalize the release year to the decade of the release
int releaseYear = 1900 + releaseDate.getYear();
releaseYear /= 10;
releaseYear *= 10;
return getOrCreateItem(releaseYear + "s");
}
}
}
}