org.eclipse.ui.IMemento#createChild ( )源码实例Demo

public void saveTo ( final IMemento memento )
{
    if ( memento == null )
    {
        return;
    }

    {
        final IMemento tableMemento = memento.createChild ( "tableCols" ); //$NON-NLS-1$

        for ( int i = 0; i < this.viewer.getTree ().getColumnCount (); i++ )
        {
            final TreeColumn col = this.viewer.getTree ().getColumn ( i );
            tableMemento.putInteger ( "col_" + i, col.getWidth () ); //$NON-NLS-1$
        }
    }

    for ( final ListEntry entry : this.list.getItems () )
    {
        final Item item = entry.getItem ();
        item.saveTo ( memento.createChild ( "item" ) ); //$NON-NLS-1$
    }
}
 

private void saveSelectionState(IMemento memento) {
	Object elements[]= ((IStructuredSelection) fViewer.getSelection()).toArray();
	if (elements.length > 0) {
		IMemento selectionMem= memento.createChild(TAG_SELECTED_ELEMENTS);
		for (int i= 0; i < elements.length; i++) {
			IMemento elementMem= selectionMem.createChild(TAG_SELECTED_ELEMENT);
			Object o= elements[i];
			if (o instanceof IJavaElement)
				elementMem.putString(TAG_SELECTED_ELEMENT_PATH, ((IJavaElement) elements[i]).getHandleIdentifier());
			else if (o instanceof LogicalPackage) {
				IPackageFragment[] packages=((LogicalPackage)o).getFragments();
				for (int j= 0; j < packages.length; j++) {
					IMemento packageMem= elementMem.createChild(TAG_LOGICAL_PACKAGE);
					packageMem.putString(TAG_SELECTED_ELEMENT_PATH, packages[j].getHandleIdentifier());
				}
			}
		}
	}
}
 

@Override
public void saveState ( final IMemento memento )
{
    super.saveState ( memento );
    if ( memento == null )
    {
        return;
    }

    final Resource resource = new XMIResourceFactoryImpl ().createResource ( null );
    resource.getContents ().add ( this.configuration );

    final ByteArrayOutputStream outputStream = new ByteArrayOutputStream ();

    final Map<?, ?> options = new HashMap<Object, Object> ();

    try
    {
        resource.save ( outputStream, options );
        final IMemento child = memento.createChild ( CHILD_CONFIGURATION );

        child.putTextData ( StringUtils.newStringUtf8 ( Base64.encodeBase64 ( outputStream.toByteArray (), true ) ) );
    }
    catch ( final Exception e )
    {
        StatusManager.getManager ().handle ( StatusHelper.convertStatus ( Activator.PLUGIN_ID, e ), StatusManager.LOG );
    }
}
 

private void saveSdkRegistry(XMLMemento memento, SdkRegistry sdkRegistry) {
       String actSdk = (sdkRegistry.getDefaultSdk() != null) ? sdkRegistry.getDefaultSdk().getName() : ""; //$NON-NLS-1$
       IPreferenceStore store = XdsCorePlugin.getDefault().getPreferenceStore();
       store.setValue(KEY_ACTIVE_SDK_NAME, actSdk);
       WorkspacePreferencesManager.getInstance().flush();

	for (Sdk sdk : sdkRegistry.getRegisteredSDKs()) {
		IMemento mementoSdk = memento.createChild(TAG_SDK);
		for (Sdk.Property property: Sdk.Property.values()) {
			mementoSdk.putString(property.xmlKey, sdk.getPropertyValue(property));
			for (Sdk.Tag tag : property.possibleTags) {
			    String val = sdk.getTag(property, tag);
			    if (val != null) {
			        String key = property.xmlKey + "_" + tag.xmlTagName; //$NON-NLS-1$
	                mementoSdk.putString(key, val);
			    }
			}
		}
		 Map<String, String> environmentVariables = sdk.getEnvironmentVariablesRaw();
		if (!environmentVariables.isEmpty()) {
			for (Map.Entry<String, String> entry : environmentVariables.entrySet()) {
				IMemento mementoEnvVar = mementoSdk.createChild(TAG_ENVIRONMENT_VARIABLE);
				mementoEnvVar.putString(TAG_ENVIRONMENT_VARIABLE_NAME,  entry.getKey());
				mementoEnvVar.putString(TAG_ENVIRONMENT_VARIABLE_VALUE, entry.getValue());
			}
		}
		saveTools(mementoSdk, sdk);
	}
}
 

private static void saveTools(IMemento memento, Sdk sdk) {
	List<SdkTool> tools = sdk.getTools();
	IMemento toolsMemento = memento.createChild(TAG_TOOL_COLLECTION);
	for (SdkTool tool : tools) {
		IMemento toolMemento = toolsMemento.createChild(TAG_TOOL);
		if (tool.isSeparator()) {
               toolMemento.putBoolean("isSeprator", true); //$NON-NLS-1$
               toolMemento.putString(SdkTool.Property.MENU_GROUP.tag, tool.getPropertyValue(SdkTool.Property.MENU_GROUP));
		} else {
               for (SdkTool.Property property: SdkTool.Property.values()) {
                   toolMemento.putString(property.tag, tool.getPropertyValue(property));
               }
		}
	}
}
 

/**
 * Save history elements to memento.
 *
 * @param memento
 *            memento to which the history will be added
 */
public void save(IMemento memento) {

	IMemento historyMemento = memento.createChild(rootNodeName);

	Object[] items = getHistoryItems();
	for (int i = 0; i < items.length; i++) {
		Object item = items[i];
		IMemento elementMemento = historyMemento
				.createChild(infoNodeName);
		storeItemToMemento(item, elementMemento);
	}

}
 

private void persistIndex(XMLMemento memento) {
  for (ICompilationUnit cu : index.getAllLeftElements()) {
    IMemento cuNode = memento.createChild(TAG_DEPENDENCIES);
    cuNode.putString(ATTR_COMPILATION_UNIT, cu.getHandleIdentifier());

    for (IPath resourcePath : index.getRightElements(cu)) {
      IMemento resNode = cuNode.createChild(TAG_RESOURCE);
      resNode.putString(ATTR_RESOURCE_PATH, resourcePath.toString());
    }
  }
}
 

protected final void saveList(IMemento memento) {
	String firstItem = combo.getText();
	IMemento child = memento.createChild(URL);
	child.putTextData(firstItem);
	
	String[] list = combo.getItems();
	for(int i = 0; i < list.length; ++i) {
		if (list[i].equals(firstItem)) {
			continue;
		}
		child = memento.createChild(URL);
		child.putTextData(list[i]);
	}
}
 

/**
 * Saves the state of the custom filters in a memento.
 *
 * @param memento the memento into which the state is saved
 */
public void saveState(IMemento memento) {
	IMemento customFilters= memento.createChild(TAG_CUSTOM_FILTERS);
	customFilters.putString(TAG_USER_DEFINED_PATTERNS_ENABLED, Boolean.toString(fUserDefinedPatternsEnabled));
	saveUserDefinedPatterns(customFilters);
	saveXmlDefinedFilters(customFilters);
	saveLRUFilters(customFilters);
}
 

private void saveXmlDefinedFilters(IMemento memento) {
	IMemento xmlDefinedFilters= memento.createChild(TAG_XML_DEFINED_FILTERS);

	for (Iterator<FilterItem> iterator= fFilterItems.values().iterator(); iterator.hasNext();) {
		FilterItem item= iterator.next();

		IMemento child= xmlDefinedFilters.createChild(TAG_CHILD);
		child.putString(TAG_FILTER_ID, item.id);
		child.putString(TAG_IS_ENABLED, String.valueOf(item.enabled));
	}
}
 

/**
 * Stores the last recently used filter Ids into
 * the given memento
 *
 * @param memento the memento into which to store the LRU filter Ids
 * @since 3.0
 */
private void saveLRUFilters(IMemento memento) {
	if(fLRUFilterIdsStack != null && !fLRUFilterIdsStack.isEmpty()) {
		IMemento lruFilters= memento.createChild(TAG_LRU_FILTERS);
		Iterator<String> iter= fLRUFilterIdsStack.iterator();
		while (iter.hasNext()) {
			String id= iter.next();
			IMemento child= lruFilters.createChild(TAG_CHILD);
			child.putString(TAG_FILTER_ID, id);
		}
	}
}
 

private void saveUserDefinedPatterns(IMemento memento) {
	if(fUserDefinedPatterns != null && fUserDefinedPatterns.length > 0) {
		IMemento userDefinedPatterns= memento.createChild(TAG_USER_DEFINED_PATTERNS);
		for (int i= 0; i < fUserDefinedPatterns.length; i++) {
			IMemento child= userDefinedPatterns.createChild(TAG_CHILD);
			child.putString(TAG_PATTERN, fUserDefinedPatterns[i]);
		}
	}
}
 

/**
 * Save the most-recently-used history in the history file
 */
public IStatus saveState(IMemento memento) {
	Iterator<TmxEditorHistoryItem> iterator = fifoList.iterator();
	while (iterator.hasNext()) {
		TmxEditorHistoryItem item = iterator.next();
		if (item.canSave()) {
			IMemento itemMemento = memento.createChild(rootTag);
			item.saveState(itemMemento);
		}
	}
	return Status.OK_STATUS;
}
 

/**
 * Given the rootMemento, gets the memento that already exists for the
 * palette entry or creates a new one in the rootMemento (and the necessary
 * palette container mementos) if one does not exist yet. The root memento's
 * tree structure matches that of the palette root. If a palette entry in
 * stack A, in drawer B is customized, the root memento will have a child
 * memento for drawer B which has a child memento for stack A which has a
 * child memento for the entry. The memento's use the palette entry's id.
 * 
 * @param rootMemento
 *            the root memento representing the palette root
 * @param paletteEntry
 *            the palette entry for which a memento should be retrieved or
 *            created
 * @return returns the memento that already exists for the palette entry or
 *         creates a new one in the rootMemento if one does not exist yet or
 *         null if the memento could not be created (most likely because the
 *         palete id is not acceptable).
 */
private IMemento getMementoForEntry(IMemento rootMemento, PaletteEntry paletteEntry) {

	ArrayList<String> idList = new ArrayList<String>();
	idList.add(paletteEntry.getId());

	PaletteContainer parent = paletteEntry.getParent();
	while (parent != null && !PaletteRoot.PALETTE_TYPE_ROOT.equals(parent.getType())) {
		idList.add(parent.getId());
		parent = parent.getParent();
	}

	// go through ids in reverse order and create the mementos as necessary
	IMemento containerMemento = rootMemento;
	for (int i = idList.size() - 1; i >= 0; i--) {
		String id = idList.get(i);
		IMemento memento = containerMemento.getChild(id);
		if (memento == null) {
			try {
				memento = containerMemento.createChild(id);
			} catch (Exception e) {
				Trace.catching(GefPlugin.getInstance(), GefDebugOptions.EXCEPTIONS_CATCHING, getClass(),
						"Invalid palette id encountered when saving the palette customizations.", //$NON-NLS-1$
						e);
				Log.warning(GefPlugin.getInstance(), GefStatusCodes.IGNORED_EXCEPTION_WARNING,
						"Invalid palette id encountered when saving the palette customizations.", //$NON-NLS-1$
						e);
				return null;
			}
		}
		containerMemento = memento;
	}

	return containerMemento;
}