| /******************************************************************************* |
| * Copyright (c) 2000, 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.expressions; |
| |
| import org.w3c.dom.Element; |
| import org.w3c.dom.Node; |
| |
| import org.eclipse.core.internal.expressions.CompositeExpression; |
| import org.eclipse.core.internal.expressions.ExpressionMessages; |
| import org.eclipse.core.internal.expressions.ExpressionPlugin; |
| import org.eclipse.core.internal.expressions.Messages; |
| |
| import org.eclipse.core.runtime.Assert; |
| import org.eclipse.core.runtime.CoreException; |
| import org.eclipse.core.runtime.IConfigurationElement; |
| import org.eclipse.core.runtime.IExtension; |
| import org.eclipse.core.runtime.IStatus; |
| import org.eclipse.core.runtime.Status; |
| |
| /** |
| * An expression converter converts an XML expression represented by an |
| * {@link IConfigurationElement} or {@link Element} (DOM) subtree into a |
| * corresponding expression tree. |
| * |
| * <p> |
| * An expression converter manages a list of {@link ElementHandler}s. Element |
| * handlers are responsible to do the actual conversion. The element handlers |
| * build a chain of responsibility. |
| * </p> |
| * |
| * @since 3.0 |
| */ |
| public final class ExpressionConverter { |
| |
| private ElementHandler[] fHandlers; |
| private static final ExpressionConverter INSTANCE = new ExpressionConverter( |
| new ElementHandler[] { ElementHandler.getDefault() }); |
| |
| /** |
| * Returns the default expression converter. The default expression converter |
| * can cope with all expression elements defined by the common expression |
| * language. |
| * |
| * @return the default expression converter |
| */ |
| public static ExpressionConverter getDefault() { |
| return INSTANCE; |
| } |
| |
| /** |
| * Creates a new expression converter with the given list of element |
| * handlers. The element handlers build a chain of responsibility |
| * meaning that the first handler in the list is first used to |
| * convert the configuration element. If this handler isn't able |
| * to convert the configuration element the next handler in the |
| * array is used. |
| * |
| * @param handlers the array of element handlers |
| */ |
| public ExpressionConverter(ElementHandler[] handlers) { |
| Assert.isNotNull(handlers); |
| fHandlers= handlers; |
| } |
| |
| /** |
| * Converts the tree of configuration elements represented by the given |
| * root element and returns a corresponding expression tree. |
| * |
| * @param root the configuration element to be converted |
| * |
| * @return the corresponding expression tree or <code>null</code> |
| * if the configuration element cannot be converted |
| * |
| * @throws CoreException if the configuration element can't be |
| * converted. Reasons include: (a) no handler is available to |
| * cope with a certain configuration element or (b) the XML |
| * expression tree is malformed. |
| */ |
| public Expression perform(IConfigurationElement root) throws CoreException { |
| for (ElementHandler handler : fHandlers) { |
| Expression result= handler.create(this, root); |
| if (result != null) |
| return result; |
| } |
| return null; |
| } |
| |
| /** |
| * Converts the tree of DOM elements represented by the given |
| * root element and returns a corresponding expression tree. |
| * |
| * @param root the element to be converted |
| * |
| * @return the corresponding expression tree or <code>null</code> |
| * if the element cannot be converted |
| * |
| * @throws CoreException if the element can't be converted. |
| * Reasons include: (a) no handler is available to cope with |
| * a certain element or (b) the XML expression tree is malformed. |
| * |
| * @since 3.3 |
| */ |
| public Expression perform(Element root) throws CoreException { |
| for (ElementHandler handler : fHandlers) { |
| Expression result= handler.create(this, root); |
| if (result != null) |
| return result; |
| } |
| return null; |
| } |
| |
| /* package */ void processChildren(IConfigurationElement element, CompositeExpression result) throws CoreException { |
| IConfigurationElement[] children= element.getChildren(); |
| if (children != null) { |
| for (IConfigurationElement configElement : children) { |
| Expression child= perform(configElement); |
| if (child == null) |
| throw new CoreException(new Status(IStatus.ERROR, ExpressionPlugin.getPluginId(), |
| IStatus.ERROR, |
| Messages.format( |
| ExpressionMessages.Expression_unknown_element, |
| getDebugPath(configElement)), |
| null)); |
| result.add(child); |
| } |
| } |
| } |
| |
| private String getDebugPath(IConfigurationElement configurationElement) { |
| StringBuilder buf= new StringBuilder(); |
| buf.append(configurationElement.getName()); |
| Object parent= configurationElement.getParent(); |
| while (parent != null) { |
| if (parent instanceof IConfigurationElement) { |
| buf.append(" > "); //$NON-NLS-1$ |
| IConfigurationElement parent2= (IConfigurationElement) parent; |
| buf.append(parent2.getName()); |
| String id= parent2.getAttribute("id"); //$NON-NLS-1$ |
| if (id != null) |
| buf.append(" (id=").append(id).append(')'); //$NON-NLS-1$ |
| parent= parent2.getParent(); |
| } else if (parent instanceof IExtension) { |
| IExtension parent2= (IExtension) parent; |
| buf.append(" : "); //$NON-NLS-1$ |
| buf.append(parent2.getExtensionPointUniqueIdentifier()); |
| buf.append(" @ "); //$NON-NLS-1$ |
| buf.append(parent2.getContributor().getName()); |
| parent= null; |
| } else { |
| parent= null; |
| } |
| } |
| return buf.toString(); |
| } |
| |
| /* package */ void processChildren(Element element, CompositeExpression result) throws CoreException { |
| Node child = element.getFirstChild(); |
| while (child != null) { |
| if (child.getNodeType() == Node.ELEMENT_NODE) { |
| Expression exp= perform((Element)child); |
| if (exp == null) |
| throw new CoreException(new Status(IStatus.ERROR, ExpressionPlugin.getPluginId(), |
| IStatus.ERROR, |
| Messages.format( |
| ExpressionMessages.Expression_unknown_element, |
| child.getNodeName()), |
| null)); |
| result.add(exp); |
| } |
| child = child.getNextSibling(); |
| } |
| } |
| } |