/*******************************************************************************
* Copyright (c) 2000, 2009 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.core.runtime;
/**
* A configuration element, with its attributes and children,
* directly reflects the content and structure of the extension section
* within the declaring plug-in's manifest (<code>plugin.xml</code>) file.
* <p>
* This interface also provides a way to create executable extension
* objects.
* </p>
* <p>
* These registry objects are intended for relatively short-term use. Clients that
* deal with these objects must be aware that they may become invalid if the
* declaring plug-in is updated or uninstalled. If this happens, all methods except
* {@link #isValid()} will throw {@link InvalidRegistryObjectException}.
* For configuration element objects, the most common case is code in a plug-in dealing
* with extensions contributed to one of the extension points it declares.
* Code in a plug-in that has declared that it is not dynamic aware (or not
* declared anything) can safely ignore this issue, since the registry
* would not be modified while it is active. However, code in a plug-in that
* declares that it is dynamic aware must be careful when accessing the extension
* and configuration element objects because they become invalid if the contributing
* plug-in is removed. Similarly, tools that analyze or display the extension registry
* are vulnerable. Client code can pre-test for invalid objects by calling {@link #isValid()},
* which never throws this exception. However, pre-tests are usually not sufficient
* because of the possibility of the extension or configuration element object becoming
* invalid as a result of a concurrent activity. At-risk clients must treat
* <code>InvalidRegistryObjectException</code> as if it were a checked exception.
* Also, such clients should probably register a listener with the extension registry
* so that they receive notification of any changes to the registry.
* </p><p>
* This interface can be used without OSGi running.
* </p><p>
* This interface is not intended to be implemented by clients.
* </p>
* @noimplement This interface is not intended to be implemented by clients.
*/
public interface IConfigurationElement {
/**
* Creates and returns a new instance of the executable extension
* identified by the named attribute of this configuration element.
* The named attribute value must contain a fully qualified name
* of a Java class. The class can either refer to a class implementing
* the executable extension or to a factory capable of returning the
* executable extension.
* <p>
* The specified class is instantiated using its 0-argument public constructor.
* <p>
* Then the following checks are done:<br>
* If the specified class implements the {@link IExecutableExtension}
* interface, the method {@link IExecutableExtension#setInitializationData(IConfigurationElement, String, Object)}
* is called, passing to the object the configuration information that was used to create it.
* <p>
* If the specified class implements {@link IExecutableExtensionFactory}
* interface, the method {@link IExecutableExtensionFactory#create()}
* is invoked.
* </p>
* <p>
* Unlike other methods on this object, invoking this method may activate
* the plug-in.
* </p>
*
* @param propertyName the name of the property
* @return the executable instance
* @exception CoreException if an instance of the executable extension
* could not be created for any reason
* @see IExecutableExtension#setInitializationData(IConfigurationElement, String, Object)
* @see IExecutableExtensionFactory
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public Object createExecutableExtension(String propertyName) throws CoreException;
/**
* Returns the named attribute of this configuration element, or
* <code>null</code> if none.
* <p>
* The names of configuration element attributes
* are the same as the attribute names of the corresponding XML element.
* For example, the configuration markup
* <pre>
* <bg pattern="stripes"/>
* </pre>
* corresponds to a configuration element named <code>"bg"</code>
* with an attribute named <code>"pattern"</code>
* with attribute value <code>"stripes"</code>.
* </p>
* <p> Note that any translation specified in the plug-in manifest
* file is automatically applied.
* </p>
*
* @param name the name of the attribute
* @return attribute value, or <code>null</code> if none
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public String getAttribute(String name) throws InvalidRegistryObjectException;
/**
* When multi-language support is enabled, this method returns the named attribute of this
* configuration element in the specified locale, or <code>null</code> if none.
* <p>
* The locale matching tries to find the best match between available translations and
* the requested locale, falling back to a more generic locale ("en") when the specific
* locale ("en_US") is not available.
* </p><p>
* If multi-language support is not enabled, this method is equivalent to the method
* {@link #getAttribute(String)}.
* </p>
* @param attrName the name of the attribute
* @param locale the requested locale
* @return attribute value, or <code>null</code> if none
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @see #getAttribute(String)
* @see IExtensionRegistry#isMultiLanguage()
* @since org.eclipse.equinox.registry 3.5
*/
public String getAttribute(String attrName, String locale) throws InvalidRegistryObjectException;
/**
* Returns the named attribute of this configuration element, or
* <code>null</code> if none.
* <p>
* The names of configuration element attributes
* are the same as the attribute names of the corresponding XML element.
* For example, the configuration markup
* <pre>
* <bg pattern="stripes"/>
* </pre>
* corresponds to a configuration element named <code>"bg"</code>
* with an attribute named <code>"pattern"</code>
* with attribute value <code>"stripes"</code>.
* </p>
* <p>
* Note that any translation specified in the plug-in manifest
* file for this attribute is <b>not</b> automatically applied.
* </p>
*
* @param name the name of the attribute
* @return attribute value, or <code>null</code> if none
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @deprecated The method is equivalent to the {@link #getAttribute(String)}. Contrary to its description,
* this method returns a translated value. Use the {@link #getAttribute(String)} method instead.
*/
public String getAttributeAsIs(String name) throws InvalidRegistryObjectException;
/**
* Returns the names of the attributes of this configuration element.
* Returns an empty array if this configuration element has no attributes.
* <p>
* The names of configuration element attributes
* are the same as the attribute names of the corresponding XML element.
* For example, the configuration markup
* <pre>
* <bg color="blue" pattern="stripes"/>
* </pre>
* corresponds to a configuration element named <code>"bg"</code>
* with attributes named <code>"color"</code>
* and <code>"pattern"</code>.
* </p>
*
* @return the names of the attributes
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public String[] getAttributeNames() throws InvalidRegistryObjectException;
/**
* Returns all configuration elements that are children of this
* configuration element.
* Returns an empty array if this configuration element has no children.
* <p>
* Each child corresponds to a nested
* XML element in the configuration markup.
* For example, the configuration markup
* <pre>
* <view>
* <verticalHint>top</verticalHint>
* <horizontalHint>left</horizontalHint>
* </view>
* </pre>
* corresponds to a configuration element, named <code>"view"</code>,
* with two children.
* </p>
*
* @return the child configuration elements
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @see #getChildren(String)
*/
public IConfigurationElement[] getChildren() throws InvalidRegistryObjectException;
/**
* Returns all child configuration elements with the given name.
* Returns an empty array if this configuration element has no children
* with the given name.
*
* @param name the name of the child configuration element
* @return the child configuration elements with that name
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @see #getChildren()
*/
public IConfigurationElement[] getChildren(String name) throws InvalidRegistryObjectException;
/**
* Returns the extension that declares this configuration element.
*
* @return the extension
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public IExtension getDeclaringExtension() throws InvalidRegistryObjectException;
/**
* Returns the name of this configuration element.
* The name of a configuration element is the same as
* the XML tag of the corresponding XML element.
* For example, the configuration markup
* <pre>
* <wizard name="Create Project"/>
* </pre>
* corresponds to a configuration element named <code>"wizard"</code>.
*
* @return the name of this configuration element
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public String getName() throws InvalidRegistryObjectException;
/**
* Returns the element which contains this element. If this element
* is an immediate child of an extension, the
* returned value can be downcast to <code>IExtension</code>.
* Otherwise the returned value can be downcast to
* <code>IConfigurationElement</code>.
*
* @return the parent of this configuration element
* or <code>null</code>
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @since 3.0
*/
public Object getParent() throws InvalidRegistryObjectException;
/**
* Returns the text value of this configuration element.
* For example, the configuration markup
* <pre>
* <script lang="javascript">.\scripts\cp.js</script>
* </pre>
* corresponds to a configuration element <code>"script"</code>
* with value <code>".\scripts\cp.js"</code>.
* <p> Values may span multiple lines (i.e., contain carriage returns
* and/or line feeds).
* <p> Note that any translation specified in the plug-in manifest
* file is automatically applied.
* </p>
*
* @return the text value of this configuration element or <code>null</code>
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
*/
public String getValue() throws InvalidRegistryObjectException;
/**
* When multi-language support is enabled, this method returns the text value of this
* configuration element in the specified locale, or <code>null</code> if none.
* <p>
* The locale matching tries to find the best match between available translations and
* the requested locale, falling back to a more generic locale ("en") when the specific
* locale ("en_US") is not available.
* </p><p>
* If multi-language support is not enabled, this method is equivalent to the method
* {@link #getValue()}.
* </p>
* @param locale the requested locale
* @return the text value of this configuration element in the specified locale,
* or <code>null</code>
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @see #getValue(String)
* @see IExtensionRegistry#isMultiLanguage()
* @since org.eclipse.equinox.registry 3.5
*/
public String getValue(String locale) throws InvalidRegistryObjectException;
/**
* Returns the untranslated text value of this configuration element.
* For example, the configuration markup
* <pre>
* <script lang="javascript">.\scripts\cp.js</script>
* </pre>
* corresponds to a configuration element <code>"script"</code>
* with value <code>".\scripts\cp.js"</code>.
* <p> Values may span multiple lines (i.e., contain carriage returns
* and/or line feeds).
* <p>
* Note that translation specified in the plug-in manifest
* file is <b>not</b> automatically applied.
* For example, the configuration markup
* <pre>
* <tooltip>#hattip</tooltip>
* </pre>
* corresponds to a configuration element, named <code>"tooltip"</code>,
* with value <code>"#hattip"</code>.
* </p>
*
* @return the untranslated text value of this configuration element or <code>null</code>
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @deprecated The method is equivalent to the {@link #getValue()}. Contrary to its description,
* this method returns a translated value. Use the {@link #getValue()} method instead.
*/
public String getValueAsIs() throws InvalidRegistryObjectException;
/**
* Returns the namespace for this configuration element. This value can be used
* in various global facilities to discover this configuration element's contributor.
*
* @return the namespace for this configuration element
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @see IExtensionRegistry
* @since 3.1
* @deprecated As namespace is no longer restricted to the contributor name,
* use {@link #getNamespaceIdentifier()} to obtain namespace name or {@link #getContributor()}
* to get the name of the contributor of this registry element.
* <p>
* In the past namespace was dictated by the name of the bundle. If bundle <code>org.abc</code>
* contributed registry element with Id of <code>MyId</code>, the namespace of
* the element was always set to <code>org.abc</code>, producing the qualified name of
* <code>org.abc.MyId</code>.
* </p><p>
* The namespace used to be the same as the bundle name. As a result, the {@link #getNamespace()}
* method was used both to obtain the name of the bundle and to obtain the namespace of a registry
* element.
* </p><p>
* Since 3.2, the extension registry allows elements to specify qualified name. The extension point
* of the plug-in <code>org.abc</code> could specify <code>org.zzz.MyExtPoint</code> as
* an Id. In this case, namespace name is <code>org.zzz</code>, but the contributor
* name is <code>org.abc</code>.
* </p><p>
* (The use of a simple Id is still a preferred way. Whenever possible, specify only the simple
* Id and let runtime take care of the rest.)
* </p><p>
* If your code used the {@link #getNamespace()} to obtain the name of the contributing bundle,
* use {@link #getContributor()}. The typical usage pattern here is to find a bundle name to obtain
* some information from the corresponding OSGi bundle. For example, deducing the file location
* specified as a relative path to the bundle install location would fall into this group.
* </p><p>
* If your code used the {@link #getNamespace()} to obtain the namespace of the registry element,
* use {@link #getNamespaceIdentifier()}. Typically, this is the case when code is trying to process
* registry elements belonging to some logical group. For example, processing notifications for all
* elements belonging to the <code>org.abc</code> namespace would fall into this category.
* </p>
*/
public String getNamespace() throws InvalidRegistryObjectException;
/**
* Returns the namespace name for this configuration element.
*
* @return the namespace name for this configuration element
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @since org.eclipse.equinox.registry 3.2
*/
public String getNamespaceIdentifier() throws InvalidRegistryObjectException;
/**
* Returns the contributor of this configuration element.
*
* @return the contributor for this configuration element
* @throws InvalidRegistryObjectException if this configuration element is no longer valid
* @since org.eclipse.equinox.registry 3.2
*/
public IContributor getContributor() throws InvalidRegistryObjectException;
/* (non-javadoc)
* @see Object#equals(java.lang.Object)
*/
public boolean equals(Object o);
/**
* Returns whether this configuration element object is valid.
*
* @return <code>true</code> if the object is valid, and <code>false</code>
* if it is no longer valid
* @since 3.1
*/
public boolean isValid();
}