Attachment 85334 Details for Bug 212518 – Immutable constant/static value observable

[patch] Immutable constant/static value observable

ConstantValue3.patch (text/plain), 7.33 KB, created by Matt Carter

on 2007-12-15 11:27:34 EST

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Creator: Matt Carter

Created: 2007-12-15 11:27:34 EST

Size: 7.33 KB

patch

obsolete

>### Eclipse Workspace Patch 1.0
>#P org.eclipse.core.databinding
>Index: src/org/eclipse/core/databinding/observable/Observables.java
>===================================================================
>RCS file: /cvsroot/eclipse/org.eclipse.core.databinding/src/org/eclipse/core/databinding/observable/Observables.java,v
>retrieving revision 1.3
>diff -u -r1.3 Observables.java
>--- src/org/eclipse/core/databinding/observable/Observables.java	22 Nov 2007 21:56:15 -0000	1.3
>+++ src/org/eclipse/core/databinding/observable/Observables.java	15 Dec 2007 16:27:02 -0000
>@@ -7,6 +7,7 @@
>  *
>  * Contributors:
>  *     Brad Reynolds - initial API and implementation
>+ *     Matt Carter - Bug 212518 - Static value observable
>  ******************************************************************************/
> 
> package org.eclipse.core.databinding.observable;
>@@ -21,6 +22,7 @@
> import org.eclipse.core.databinding.observable.set.ISetChangeListener;
> import org.eclipse.core.databinding.observable.set.ObservableSet;
> import org.eclipse.core.databinding.observable.value.IObservableValue;
>+import org.eclipse.core.internal.databinding.observable.ConstantValue;
> import org.eclipse.core.internal.databinding.observable.EmptyObservableList;
> import org.eclipse.core.internal.databinding.observable.EmptyObservableSet;
> import org.eclipse.core.internal.databinding.observable.ProxyObservableSet;
>@@ -126,6 +128,68 @@
> 	}
> 
> 	/**
>+	 * Returns a constant observable value which can be observed but on which
>+	 * set operations will fail.
>+	 * 
>+	 * @param realm
>+	 * @param value
>+	 *            static value for this observable
>+	 * @param type
>+	 * @return constant value observable
>+	 */
>+	public static IObservableValue staticObservableValue(Realm realm,
>+			Object value, Class type) {
>+		return new ConstantValue(realm, value, type);
>+	}
>+	
>+	/**
>+	 * Returns a constant observable value which can be observed but on which
>+	 * set operations will fail.
>+	 * 
>+	 * @note It is recommended that you use a version of this method which
>+	 *       accepts a type argument and explicitly specify the type when it is
>+	 *       known. This method will use a type of Object.class.
>+	 * 
>+	 * @param realm
>+	 * @param value
>+	 *            static value for this observable
>+	 * @return constant value observable
>+	 */
>+	public static IObservableValue staticObservableValue(Realm realm, Object value) {
>+		return new ConstantValue(realm, value, Object.class);
>+	}
>+
>+	/**
>+	 * Returns a constant observable value which can be observed but on which
>+	 * set operations will fail.
>+	 * 
>+	 * @param value
>+	 *            static value for this observable
>+	 * @param type
>+	 * @return constant value observable
>+	 */
>+	public static IObservableValue staticObservableValue(Object value,
>+			Class type) {
>+		return new ConstantValue(value, type);
>+	}
>+
>+	/**
>+	 * Returns a constant observable value which can be observed but on which
>+	 * set operations will fail.
>+	 * 
>+	 * @note It is recommended that you use a version of this method which
>+	 *       accepts a type argument and explicitly specify the type when it is
>+	 *       known. This method will use a type of Object.class.
>+	 * 
>+	 * @param value
>+	 *            static value for this observable
>+	 * @return constant value observable
>+	 */
>+	public static IObservableValue staticObservableValue(Object value) {
>+		return new ConstantValue(value, Object.class);
>+	}
>+		
>+	/**
> 	 * Returns an observable set that contains the same elements as the given
> 	 * set, and fires the same events as the given set, but can be disposed of
> 	 * without disposing of the wrapped set.
>Index: src/org/eclipse/core/internal/databinding/observable/ConstantValue.java
>===================================================================
>RCS file: src/org/eclipse/core/internal/databinding/observable/ConstantValue.java
>diff -N src/org/eclipse/core/internal/databinding/observable/ConstantValue.java
>--- /dev/null	1 Jan 1970 00:00:00 -0000
>+++ src/org/eclipse/core/internal/databinding/observable/ConstantValue.java	1 Jan 1970 00:00:00 -0000
>@@ -0,0 +1,123 @@
>+/*******************************************************************************
>+ * Copyright (c) 2005, 2007 Matt Carter and others.
>+ * All rights reserved. This program and the accompanying materials
>+ * are made available under the terms of the Eclipse Public License v1.0
>+ * which accompanies this distribution, and is available at
>+ * http://www.eclipse.org/legal/epl-v10.html
>+ *
>+ * Contributors:
>+ *     Matt Carter - Initial API and implementation
>+ *                 - Bug 212518 - Static value observable
>+ *******************************************************************************/
>+package org.eclipse.core.internal.databinding.observable;
>+
>+import org.eclipse.core.databinding.observable.IChangeListener;
>+import org.eclipse.core.databinding.observable.IStaleListener;
>+import org.eclipse.core.databinding.observable.ObservableTracker;
>+import org.eclipse.core.databinding.observable.Realm;
>+import org.eclipse.core.databinding.observable.value.IObservableValue;
>+import org.eclipse.core.databinding.observable.value.IValueChangeListener;
>+import org.eclipse.core.databinding.observable.value.WritableValue;
>+import org.eclipse.core.runtime.Assert;
>+import org.eclipse.core.runtime.AssertionFailedException;
>+
>+/**
>+ * Constant, read-only observable value which can be observed but not changed.
>+ * 
>+ * @see WritableValue
>+ */
>+public class ConstantValue implements IObservableValue {
>+
>+	final Object type;
>+	final Object object;
>+	final Realm realm;
>+
>+	/**
>+	 * Construct a constant value of the given type, in the default realm. 
>+	 * @param object immutable value
>+	 * @param type type
>+	 */
>+	public ConstantValue(Object object, Object type) {
>+		this.realm = Realm.getDefault();
>+		this.object = object;
>+		this.type = type;
>+	}
>+
>+	/**
>+	 * Construct a constant value of the given type, in the given realm. 
>+	 * @param realm Realm 
>+	 * @param object immutable value
>+	 * @param type type
>+	 */
>+	public ConstantValue(Realm realm, Object object, Object type) {
>+		Assert.isNotNull(realm);
>+		this.realm = realm;
>+		this.object = object;
>+		this.type = type;
>+	}
>+
>+	public Object getValueType() {
>+		return type;
>+	}
>+
>+	/**
>+	 * Returns the constant value.  Must be invoked in the {@link Realm} of the observable.
>+	 * 
>+	 * @return the constant value
>+	 * @TrackedGetter
>+	 */	
>+	public Object getValue() {
>+		checkRealm();
>+		ObservableTracker.getterCalled(this);
>+		return object;
>+	}
>+
>+	public void setValue(Object value) {
>+		throw new UnsupportedOperationException();
>+	}
>+
>+	public void addValueChangeListener(IValueChangeListener listener) {
>+		// ignore
>+	}
>+
>+	public void removeValueChangeListener(IValueChangeListener listener) {
>+		// ignore
>+	}
>+
>+	public void addChangeListener(IChangeListener listener) {
>+		// ignore		
>+	}
>+
>+	public void addStaleListener(IStaleListener listener) {
>+		// ignore
>+	}
>+
>+	public void dispose() {
>+		// nothing to dispose
>+	}
>+
>+	public Realm getRealm() {
>+		return realm;
>+	}
>+
>+	public boolean isStale() {
>+		return false;
>+	}
>+
>+	public void removeChangeListener(IChangeListener listener) {
>+		// ignore
>+	}
>+
>+	public void removeStaleListener(IStaleListener listener) {
>+		// ignore
>+	}
>+	/**
>+	 * Asserts that the realm is the current realm.
>+	 * 
>+	 * @see Realm#isCurrent()
>+	 * @throws AssertionFailedException if the realm is not the current realm
>+	 */
>+	protected void checkRealm() {
>+		Assert.isTrue(getRealm().isCurrent());
>+	}	
>+}

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Attachments on bug 212518: 84944 | 85041 | 85043 | 85094 | 85095 | 85100 | 85334 | 89221 | 89222