jtablebinding.java

java属性邦定的（JSR-295）的一个实现

/*
 * Copyright (C) 2007 Sun Microsystems, Inc. All rights reserved. Use is
 * subject to license terms.
 */

package org.jdesktop.swingbinding;

import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;
import java.util.*;
import java.util.concurrent.CopyOnWriteArrayList;
import org.jdesktop.beansbinding.BindingListener;
import org.jdesktop.beansbinding.Binding.*;
import org.jdesktop.beansbinding.AutoBinding;
import org.jdesktop.beansbinding.Property;
import org.jdesktop.beansbinding.PropertyStateEvent;
import org.jdesktop.beansbinding.PropertyStateListener;
import org.jdesktop.swingbinding.impl.AbstractColumnBinding;
import org.jdesktop.swingbinding.impl.ListBindingManager;
import static org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.*;

/**
 * Binds a {@code List} of objects to act as the rows of a {@code JTable}.
 * Each object in the source {@code List} represents one row in the {@code JTable}.
 * Mappings from properties of the source objects to columns are created by
 * adding {@link org.jdesktop.swingbinding.JTableBinding.ColumnBinding ColumnBindings}
 * to a {@code JTableBinding}. Instances of {@code JTableBinding} are obtained by
 * calling one of the {@code createJTableBinding} methods in the {@code SwingBindings}
 * class.
 * <p>
 * Here is an example of creating a binding from a {@code List} of {@code Person}
 * objects to a {@code JTable}:
 * <p>
 * <pre><code>
 *    // create the person List
 *    List<Person> people = createPersonList();
 *
 *    // create the binding from List to JTable
 *    JTableBinding tb = SwingBindings.createJTableBinding(READ, people, jTable);
 *
 *    // define the properties to be used for the columns
 *    BeanProperty firstNameP = BeanProperty.create("firstName");
 *    BeanProperty lastNameP = BeanProperty.create("lastName");
 *    BeanProperty ageP = BeanProperty.create("age");
 *
 *    // configure how the properties map to columns
 *    tb.addColumnBinding(firstNameP).setColumnName("First Name");
 *    tb.addColumnBinding(lastNameP).setColumnName("Last Name");
 *    tb.addColumnBinding(ageP).setColumnName("Age").setColumnClass(Integer.class);
 *
 *    // realize the binding
 *    tb.bind();
 * </code></pre>
 * <p>
 * The {@code JTable} target of a {@code JTableBinding} acts as a live view of
 * the objects in the source {@code List},
 * regardless of the update strategy (the meaning of the update strategy is
 * <a href="#CLARIFICATION">clarified later</a> in this document). {@code JTableBinding}
 * listens to the properties specified for the {@code ColumnBindings}, 
 * for all objects in the {@code List}, and updates the values
 * displayed in the {@code JTable} in response to change. All successful
 * edits made to {@code JTable} cell values are immediately committed back to
 * corresponding objects in the source {@code List}. If the {@code List} is an
 * instance of {@code ObservableList}, then changes to the {@code List} contents
 * (such as adding, removing or replacing an object) are also reflected in the
 * {@code JTable}. <b>Important:</b> Changing the contents of a non-observable
 * {@code List} while it is participating in a {@code JTableBinding} is unsupported,
 * resulting in undefined behavior and possible exceptions.
 * <p>
 * <a name="EDITABILITY">A cell</a> in the {@code JTable} is editable for any given row and
 * column when all of the following are true: the property specified for that column
 * by its {@code ColumnBinding} is writeable for the object representing that row,
 * the {@code "editable"} property of the {@code JTableBinding} is {@code true}
 * (the default), and the {@code "editable"} property of the {@code ColumnBinding}
 * is {@code true} (the default).
 * <p>
 * <a name="CLARIFICATION">{@code JTableBinding} requires</a>
 * extra clarification on the operation of the
 * {@code refresh} and {@code save} methods and the meaning of the update
 * strategy. The target property of a {@code JTableBinding} is not the
 * target {@code JTable} property provided in the constructor, but rather a
 * private synthetic property representing the {@code List} of objects to show
 * in the target {@code JTable}. This synthetic property is readable/writeable
 * only when the {@code JTableBinding} is bound and the target {@code JTable}
 * property is readable with a {@code non-null} value.
 * <p>
 * It is this private synthetic property on which the {@code refresh} and
 * {@code save} methods operate; meaning that these methods simply cause syncing
 * between the value of the source {@code List} property and the value of the
 * synthetic target property (representing the {@code List} to be shown in the
 * target {@code JTable}). These methods do not, therefore, have anything to do
 * with refreshing or saving <i>values</i> in the {@code JTable}. Likewise, the update
 * strategy, which simply controls when {@code refresh} and {@code save} are
 * automatically called, also has nothing to do with refreshing or saving
 * <i>values</i> in the {@code JTable}.
 * <p>
 * <b>Note:</b> At the current time, the {@code READ_WRITE} update strategy
 * is not useful for {@code JTableBinding}. To prevent unwanted confusion,
 * {@code READ_WRITE} is translated to {@code READ} by {@code JTableBinding's}
 * constructor.
 * <p>
 * {@code JTableBinding} works by installing a custom model on the target
 * {@code JTable}, as appropriate, to represent the source {@code List}. The
 * model is installed on a target {@code JTable} with the first succesful call
 * to {@code refresh} with that {@code JTable} as the target. Subsequent calls
 * to {@code refresh} update the elements in this already-installed model.
 * The model is uninstalled from a target {@code JTable} when either the
 * {@code JTableBinding} is unbound or when the target {@code JTable} property
 * changes to no longer represent that {@code JTable}. Note: When the model is
 * uninstalled from a {@code JTable}, it is replaced with a {@code DefaultTableModel},
 * in order to leave the {@code JTable} functional.
 * <p>
 * Some of the above is easier to understand with an example. Let's consider
 * a {@code JTableBinding} ({@code binding}), with update strategy
 * {@code READ}, between a property representing a {@code List} ({@code listP})
 * and a property representing a {@code JTable} ({@code jTableP}). {@code listP}
 * and {@code jTableP} both start off readable, referring to a {@code non-null}
 * {@code List} and {@code non-null} {@code JTable} respectively. Let's look at
 * what happens for each of a sequence of events:
 * <p>
 * <table border=1>
 *   <tr><th>Sequence</th><th>Event</th><th>Result</th></tr>
 *   <tr valign="baseline">
 *     <td align="center">1</td>
 *     <td>explicit call to {@code binding.bind()}</td>
 *     <td>
 *         - synthetic target property becomes readable/writeable
 *         <br>
 *         - {@code refresh()} is called
 *         <br>
 *         - model is installed on target {@code JTable}, representing list of objects
 *     </td>
 *   </tr>
 *   <tr valign="baseline">
 *     <td align="center">2</td>
 *     <td>{@code listP} changes to a new {@code List}</td>
 *     <td>
 *         - {@code refresh()} is called
 *         <br>
 *         - model is updated with new list of objects
 *     </td>
 *   </tr>
 *   <tr valign="baseline">
 *     <td align="center"><a name="STEP3" href="#NOTICE">3</a></td>
 *     <td>{@code jTableP} changes to a new {@code JTable}</td>
 *     <td>
 *         - model is uninstalled from old {@code JTable}
 *     </td>
 *   </tr>
 *   <tr valign="baseline">
 *     <td align="center">4</td>
 *     <td>explicit call to {@code binding.refresh()}</td>
 *     <td>
 *         - model is installed on target {@code JTable}, representing list of objects
 *     </td>
 *   </tr>
 *   <tr valign="baseline">
 *     <td align="center">5</td>
 *     <td>{@code listP} changes to a new {@code List}</td>
 *     <td>
 *         - {@code refresh()} is called
 *         <br>
 *         - model is updated with new list of objects
 *     </td>
 *   </tr>
 *   <tr valign="baseline">
 *     <td align="center">6</td>
 *     <td>explicit call to {@code binding.unbind()}</td>
 *     <td>
 *         - model is uninstalled from target {@code JTable}
 *     </td>
 *   </tr>
 * </table>
 * <p>
 * <a name="NOTICE">Notice</a> that in <a href="#STEP3">step 3</a>, when the value
 * of the {@code JTable} property changed, the new {@code JTable} did not
 * automatically get the model with the elements applied to it. A change to the
 * target value should not cause an {@code AutoBinding} to sync the target from
 * the source. Step 4 forces a sync by explicitly calling {@code refresh}.
 * Alternatively, it could be caused by any other action that results
 * in a {@code refresh} (for example, the source property changing value, or an
 * explicit call to {@code unbind} followed by {@code bind}).
 * <p>
 * {@code ColumnBindings} are managed by the {@code JTableBinding}. They are not
 * to be explicitly bound, unbound, added to a {@code BindingGroup}, or accessed
 * in a way that is not allowed for a managed binding. {@code BindingListeners}
 * added to a {@code ColumnBinding} are notified at the time an edited {@code JTable} value
 * is to be committed back to the source {@code List}. They receive notification of either
 * {@code synced} or {@code syncFailed}. {@code BindingListeners} added to the
 * {@code JTableBinding} itself are also notified of {@code sync} and {@code syncFailed}
 * for the {@code JTableBinding's ColumnBindings}.
 * <p>
 * In addition to binding the elements of a {@code JTable}, it is possible to
 * bind to the selection of a {@code JTable}. When binding to the selection of a {@code JTable}
 * backed by a {@code JTableBinding}, the selection is always in terms of elements
 * from the source {@code List}. See the list of <a href="package-summary.html#SWING_PROPS">
 * interesting swing properties</a> in the package summary for more details.
 *
 * @param <E> the type of elements in the source {@code List}
 * @param <SS> the type of source object (on which the source property resolves to {@code List})
 * @param <TS> the type of target object (on which the target property resolves to {@code JTable})
 *
 * @author Shannon Hickey
 */
public final class JTableBinding<E, SS, TS> extends AutoBinding<SS, List<E>, TS, List> {

    private Property<TS, ? extends JTable> tableP;
    private ElementsProperty<TS> elementsP;
    private Handler handler = new Handler();
    private JTable table;
    private BindingTableModel model;
    private boolean editable = true;
    private List<ColumnBinding> columnBindings = new ArrayList<ColumnBinding>();

    /**
     * Constructs an instance of {@code JTableBinding}.
     *
     * @param strategy the update strategy
     * @param sourceObject the source object
     * @param sourceListProperty a property on the source object that resolves to the {@code List} of elements
     * @param targetObject the target object
     * @param targetJTableProperty a property on the target object that resolves to a {@code JTable}
     * @param name a name for the {@code JTableBinding}
     * @throws IllegalArgumentException if the source property or target property is {@code null}
     */
    protected JTableBinding(UpdateStrategy strategy, SS sourceObject, Property<SS, List<E>> sourceListProperty, TS targetObject, Property<TS, ? extends JTable> targetJTableProperty, String name) {
        super(strategy == READ_WRITE ? READ : strategy,
              sourceObject, sourceListProperty, targetObject, new ElementsProperty<TS>(), name);

        if (targetJTableProperty == null) {
            throw new IllegalArgumentException("target JTable property can't be null");
        }

        tableP = targetJTableProperty;
        elementsP = (ElementsProperty<TS>)getTargetProperty();
    }

    protected void bindImpl() {
        elementsP.setAccessible(isTableAccessible());
        tableP.addPropertyStateListener(getTargetObject(), handler);
        elementsP.addPropertyStateListener(null, handler);
        super.bindImpl();
    }

    protected void unbindImpl() {
        elementsP.removePropertyStateListener(null, handler);
        tableP.removePropertyStateListener(getTargetObject(), handler);
        elementsP.setAccessible(false);
        cleanupForLast();
        super.unbindImpl();
    }

    private boolean isTableAccessible() {
        return tableP.isReadable(getTargetObject()) && tableP.getValue(getTargetObject()) != null;
    }

    private boolean isTableAccessible(Object value) {
        return value != null && value != PropertyStateEvent.UNREADABLE;
    }

    private void cleanupForLast() {
        if (table == null) {
            return;
        }

        table.setModel(new DefaultTableModel());
        table = null;
        model.setElements(null, true);
        model = null;
    }
    
    /**
     * Sets whether or not the cells of the table should be editable.
     * The default for this property is {@code true}.
     * See this <a href="#EDITABILITY">paragraph</a> in the class level
     * documentation on editability.
     *
     * @param editable whether or not the cells of the table should be editable
     */
    public void setEditable(boolean editable) {