| /******************************************************************************* |
| * Copyright (c) 2007, 2008 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.core.internal.expressions; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.eclipse.core.expressions.Expression; |
| import org.eclipse.core.expressions.ExpressionConverter; |
| |
| import org.eclipse.core.runtime.CoreException; |
| import org.eclipse.core.runtime.IConfigurationElement; |
| import org.eclipse.core.runtime.IExtensionDelta; |
| import org.eclipse.core.runtime.IExtensionRegistry; |
| import org.eclipse.core.runtime.IRegistryChangeEvent; |
| import org.eclipse.core.runtime.IRegistryChangeListener; |
| import org.eclipse.core.runtime.InvalidRegistryObjectException; |
| import org.eclipse.core.runtime.Platform; |
| |
| /** |
| * This manages the extension point that allows core expression reuse. |
| * |
| * @since 3.3 |
| */ |
| public class DefinitionRegistry implements IRegistryChangeListener { |
| private Map<String, Expression> cache= null; |
| |
| private Map<String, Expression> getCache() { |
| if (cache == null) { |
| cache= new HashMap<>(); |
| } |
| return cache; |
| } |
| |
| public DefinitionRegistry() { |
| Platform.getExtensionRegistry().addRegistryChangeListener(this, "org.eclipse.core.expressions"); //$NON-NLS-1$ |
| } |
| |
| /** |
| * Get the expression with the id defined by an extension. This class will |
| * cache the expressions when appropriate, so it's OK to always ask the |
| * registry. |
| * |
| * @param id The unique ID of the expression definition |
| * @return the expression |
| * @throws CoreException If the expression cannot be found. |
| */ |
| public Expression getExpression(String id) throws CoreException { |
| Expression cachedExpression= getCache().get(id); |
| if (cachedExpression != null) { |
| return cachedExpression; |
| } |
| |
| IExtensionRegistry registry= Platform.getExtensionRegistry(); |
| IConfigurationElement[] ces= registry.getConfigurationElementsFor("org.eclipse.core.expressions", "definitions"); //$NON-NLS-1$ //$NON-NLS-2$ |
| |
| Expression foundExpression= null; |
| for (IConfigurationElement ce : ces) { |
| String cid= ce.getAttribute("id"); //$NON-NLS-1$ |
| if (cid != null && cid.equals(id)) { |
| try { |
| foundExpression= getExpression(id, ce); |
| break; |
| } catch (InvalidRegistryObjectException e) { |
| throw new CoreException(new ExpressionStatus(ExpressionStatus.MISSING_EXPRESSION, Messages.format( |
| ExpressionMessages.Missing_Expression, id))); |
| } |
| } |
| } |
| if (foundExpression == null) { |
| throw new CoreException(new ExpressionStatus(ExpressionStatus.MISSING_EXPRESSION, Messages.format( |
| ExpressionMessages.Missing_Expression, id))); |
| } |
| return foundExpression; |
| } |
| |
| private Expression getExpression(String id, IConfigurationElement element) throws InvalidRegistryObjectException, |
| CoreException { |
| Expression expr= ExpressionConverter.getDefault().perform(element.getChildren()[0]); |
| if (expr != null) { |
| getCache().put(id, expr); |
| } |
| return expr; |
| } |
| |
| @Override |
| public void registryChanged(IRegistryChangeEvent event) { |
| IExtensionDelta[] extensionDeltas= event.getExtensionDeltas("org.eclipse.core.expressions", "definitions"); //$NON-NLS-1$//$NON-NLS-2$ |
| for (IExtensionDelta extensionDelta : extensionDeltas) { |
| if (extensionDelta.getKind() == IExtensionDelta.REMOVED) { |
| IConfigurationElement[] ces= extensionDelta.getExtension().getConfigurationElements(); |
| for (IConfigurationElement ce : ces) { |
| String id= ce.getAttribute("id"); //$NON-NLS-1$ |
| if (id != null) { |
| getCache().remove(id); |
| } |
| } |
| } |
| } |
| } |
| } |