org.eclipse.jface.bindings

Class Binding

java.lang.Object

org.eclipse.jface.bindings.Binding

Direct Known Subclasses:

KeyBinding

public abstract class Binding
extends Object

A binding is a link between user input and the triggering of a particular command. The most common example of a binding is a keyboard shortcut, but there are also mouse and gesture bindings.

Bindings are linked to particular conditions within the application. Some of these conditions change infrequently (e.g., locale, scheme), while some will tend to change quite frequently (e.g., context). This allows the bindings to be tailored to particular situations. For example, a set of bindings may be appropriate only inside a text editor. Or, perhaps, a set of bindings might be appropriate only for a given locale, such as bindings that coexist with the Input Method Editor (IME) on Chinese locales.

It is also possible to remove a particular binding. This is typically done as part of user configuration (e.g., user changing keyboard shortcuts). However, it can also be helpful when trying to change a binding on a particular locale or platform. An "unbinding" is really just a binding with no command identifier. For it to unbind a particular binding, it must match that binding in its context identifier and scheme identifier. Subclasses (e.g., KeyBinding) may require other properties to match (e.g., keySequence). If these properties match, then this is an unbinding. Note: the locale and platform can be different.

For example, imagine you have a key binding that looks like this:

 KeyBinding(command, scheme, context, "Ctrl+Shift+F")
 

On GTK+, the "Ctrl+Shift+F" interferes with some native behaviour. To change the binding, we first unbind the "Ctrl+Shift+F" key sequence by assigning it a null command on the gtk platform. We then create a new binding that maps the command to the "Esc Ctrl+F" key sequence.

     KeyBinding("Ctrl+Shift+F",null,scheme,context,null,gtk,null,SYSTEM)
     KeyBinding("Esc Ctrl+F",parameterizedCommand,scheme,context,null,gtk,SYSTEM)
 

Bindings are intended to be immutable objects.

Since:

3.1

Field Summary

Fields

Modifier and Type	Field and Description
protected String	string The string representation of this binding.
static int	SYSTEM The type of binding that is defined by the system (i.e., by the application developer).
static int	USER The type of binding that is defined by the user (i.e., by the end user of the application).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Binding(ParameterizedCommand command, String schemeId, String contextId, String locale, String platform, String windowManager, int type) Constructs a new instance of Binding.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object object) Tests whether this binding is equal to another object.
String	getContextId() Returns the identifier of the context in which this binding applies.
String	getLocale() Returns the locale in which this binding applies.
ParameterizedCommand	getParameterizedCommand() Returns the parameterized command to which this binding applies.
String	getPlatform() Returns the platform on which this binding applies.
String	getSchemeId() Returns the identifier of the scheme in which this binding applies.
abstract TriggerSequence	getTriggerSequence() Returns the sequence of trigger for a given binding.
int	getType() Returns the type for this binding.
int	hashCode() Computes the hash code for this key binding based on all of its attributes.
String	toString() The string representation of this binding -- for debugging purposes only.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

SYSTEM

public static final int SYSTEM

The type of binding that is defined by the system (i.e., by the application developer). In the case of an application based on the Eclipse workbench, this is the registry.

See Also:

Constant Field Values

USER

public static final int USER

The type of binding that is defined by the user (i.e., by the end user of the application). In the case of an application based on the Eclipse workbench, this is the preference store.

See Also:

Constant Field Values

string

protected transient String string

The string representation of this binding. This string is for debugging purposes only, and is not meant to be displayed to the user. This value is computed lazily.

Constructor Detail

Binding

protected Binding(ParameterizedCommand command,
                  String schemeId,
                  String contextId,
                  String locale,
                  String platform,
                  String windowManager,
                  int type)

Constructs a new instance of Binding.

Parameters:

command - The parameterized command to which this binding applies; this value may be null if the binding is meant to "unbind" a previously defined binding.

schemeId - The scheme to which this binding belongs; this value must not be null.

contextId - The context to which this binding applies; this value must not be null.

locale - The locale to which this binding applies; this value may be null if it applies to all locales.

platform - The platform to which this binding applies; this value may be null if it applies to all platforms.

windowManager - The window manager to which this binding applies; this value may be null if it applies to all window managers. This value is currently ignored.

type - The type of binding. This should be either SYSTEM or USER.

Method Detail

equals

public final boolean equals(Object object)

Tests whether this binding is equal to another object. Bindings are only equal to other bindings with equivalent values.

Overrides:

equals in class Object

Parameters:

object - The object with which to compare; may be null.

Returns:

true if the object is a binding with equivalent values for all of its properties; false otherwise.

getParameterizedCommand

public final ParameterizedCommand getParameterizedCommand()

Returns the parameterized command to which this binding applies. If the identifier is null, then this binding is "unbinding" an existing binding.

Returns:

The fully-parameterized command; may be null.

getContextId

public final String getContextId()

Returns the identifier of the context in which this binding applies.

Returns:

The context identifier; never null.

getLocale

public final String getLocale()

Returns the locale in which this binding applies. If the locale is null, then this binding applies to all locales. This string is the same format as returned by Locale.getDefault().toString().

Returns:

The locale; may be null.

getPlatform

public final String getPlatform()

Returns the platform on which this binding applies. If the platform is null, then this binding applies to all platforms. This string is the same format as returned by SWT.getPlatform().

Returns:

The platform; may be null.

getSchemeId

public final String getSchemeId()

Returns the identifier of the scheme in which this binding applies.

Returns:

The scheme identifier; never null.

getTriggerSequence

public abstract TriggerSequence getTriggerSequence()

Returns the sequence of trigger for a given binding. The triggers can be anything, but above all it must be hashable. This trigger sequence is used by the binding manager to distinguish between different bindings.

Returns:

The object representing an input event that will trigger this binding; must not be null.

getType

public final int getType()

Returns the type for this binding. As it stands now, this value will either be SYSTEM or USER. In the future, more types might be added.

Returns:

The type for this binding.

hashCode

public final int hashCode()

Computes the hash code for this key binding based on all of its attributes.

Overrides:

hashCode in class Object

Returns:

The hash code for this key binding.

toString

public String toString()

The string representation of this binding -- for debugging purposes only. This string should not be shown to an end user. This should be overridden by subclasses that add properties.

Overrides:

toString in class Object

Returns:

The string representation; never null.