Java tutorial
/** * Copyright (C) 2010 STMicroelectronics * * This file is part of "Mind Compiler" is free software: you can redistribute * it and/or modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more * details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * Contact: mind@ow2.org * * Authors: Matthieu Leclercq * Contributors: */ package org.ow2.mind.plugin; import java.io.IOException; import java.io.InputStreamReader; import java.net.MalformedURLException; import java.net.URISyntaxException; import java.net.URL; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.WeakHashMap; import java.util.regex.Pattern; import org.objectweb.fractal.adl.CompilerError; import org.objectweb.fractal.adl.error.GenericErrors; import org.w3c.dom.Element; import com.google.common.base.Function; import com.google.common.base.Predicate; import com.google.common.collect.Iterables; import com.wutka.dtd.DTD; import com.wutka.dtd.DTDAny; import com.wutka.dtd.DTDAttribute; import com.wutka.dtd.DTDCardinal; import com.wutka.dtd.DTDChoice; import com.wutka.dtd.DTDDecl; import com.wutka.dtd.DTDElement; import com.wutka.dtd.DTDEmpty; import com.wutka.dtd.DTDItem; import com.wutka.dtd.DTDName; import com.wutka.dtd.DTDParser; import com.wutka.dtd.DTDSequence; class ExtensionPointImpl implements ExtensionPoint { private static final String EXTENSION_ELEMENT_NAME = "extension"; private static final String ID_ATTR_NAME = "id"; private static final String NAME_ATTR_NAME = "name"; private static final String DTD_ATTR_NAME = "dtd"; private final String id; private final String qualifiedId; private final String name; private final Plugin plugin; private final DTD dtd; private final List<Extension> extensions; private final WeakHashMap<DTDElement, Pattern> patternCache = new WeakHashMap<DTDElement, Pattern>(); ExtensionPointImpl(final PluginImpl plugin, final Element element) { this.plugin = plugin; id = element.getAttribute(ID_ATTR_NAME); if (id == null) { throw new CompilerError(GenericErrors.INTERNAL_ERROR, "Invalid extenstion point, missing id in '" + element.getBaseURI() + "'."); } qualifiedId = plugin.getId() + "." + id; name = element.getAttribute(NAME_ATTR_NAME); extensions = new ArrayList<Extension>(); final String dtd = element.getAttribute(DTD_ATTR_NAME); if (dtd != null && dtd.length() > 0) { final URL dtdURL; try { final URL pluginURL = plugin.getDescriptorURL(); if (pluginURL.getProtocol().equals("jar")) { String path = pluginURL.getPath(); path = path.substring(0, path.lastIndexOf('!')); dtdURL = new URL(pluginURL.getProtocol(), pluginURL.getHost(), pluginURL.getPort(), path + "!/" + dtd); } else { dtdURL = pluginURL.toURI().resolve(dtd).normalize().toURL(); } } catch (final MalformedURLException e) { throw new CompilerError(GenericErrors.INTERNAL_ERROR, e, "Can't find extension point DTD '" + dtd + "'."); } catch (final URISyntaxException e) { throw new CompilerError(GenericErrors.INTERNAL_ERROR, e, "Can't find extension point DTD '" + dtd + "'."); } try { this.dtd = new DTDParser(new InputStreamReader(dtdURL.openStream())).parse(); } catch (final IOException e) { throw new CompilerError(GenericErrors.INTERNAL_ERROR, e, "Can't read extension point DTD '" + dtd + "'."); } if (this.dtd.elements.get(EXTENSION_ELEMENT_NAME) == null) { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Invalid DTD '" + dtd + "' missing definition of element '" + EXTENSION_ELEMENT_NAME + "'."); } } else { this.dtd = null; } } public String getId() { return id; } public String getQualifiedId() { return qualifiedId; } public String getName() { return name; } public Plugin getPlugin() { return plugin; } public Iterable<Extension> getExtensions() { return Iterables.unmodifiableIterable(extensions); } public Iterable<ConfigurationElement> getConfigurationElements() { return Iterables.unmodifiableIterable(Iterables .concat(Iterables.transform(extensions, new Function<Extension, Iterable<ConfigurationElement>>() { public Iterable<ConfigurationElement> apply(final Extension from) { return from.getConfigurationElements(); } }))); } public Iterable<ConfigurationElement> getConfigurationElements(final String name) { return Iterables.filter(getConfigurationElements(), new Predicate<ConfigurationElement>() { public boolean apply(final ConfigurationElement input) { return input.getName().equals(name); } }); } protected void bindExtension(final Extension extension) { extensions.add(extension); if (dtd != null) { checkElementContent(extension.getConfigurationElements(), (DTDElement) dtd.elements.get(EXTENSION_ELEMENT_NAME)); } } @SuppressWarnings("unchecked") void checkElement(final ConfigurationElement element) throws CompilerError { final String elementName = element.getName(); final DTDElement dtdElement = (DTDElement) dtd.elements.get(elementName); if (dtdElement == null) { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Invalid element name '" + elementName + "' in extension."); } final Map<String, DTDAttribute> dtdAttributes = new HashMap<String, DTDAttribute>(dtdElement.attributes); final Map<String, String> attributes = element.getAttributes(); for (final String attrName : attributes.keySet()) { final DTDAttribute dtdAttr = dtdAttributes.remove(attrName); if (dtdAttr == null) { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Invalid attribute name '" + attrName + "' in extension."); } } // scan remaining dtdAttribute and check their contingency for (final DTDAttribute dtdAttr : dtdAttributes.values()) { if (dtdAttr.defaultValue != null) { ((ConfigurationElementImpl) element).setAttribute(dtdAttr.name, dtdAttr.defaultValue); } else if (dtdAttr.getDecl().equals(DTDDecl.REQUIRED)) { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Missing attribute name '" + dtdAttr.name + "' in extension."); } } checkElementContent(element.getChildren(), dtdElement); } void checkElementContent(final Iterable<ConfigurationElement> children, final DTDElement dtdElement) throws CompilerError { if (!(dtdElement.content instanceof DTDEmpty || dtdElement.content instanceof DTDAny)) { final Pattern pattern = getPattern(dtdElement); if (!pattern.matcher(buildChildrenSequence(children)).matches()) { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Invalid content of element '" + dtdElement.name + "' in extension."); } for (final ConfigurationElement child : children) { checkElement(child); } } } String buildChildrenSequence(final Iterable<ConfigurationElement> children) { final StringBuilder sb = new StringBuilder(); for (final ConfigurationElement child : children) { sb.append(",").append(child.getName()); } return sb.toString(); } Pattern getPattern(final DTDElement element) { Pattern pattern = patternCache.get(element); if (pattern == null) { final StringBuilder sb = new StringBuilder(); buildRegExp(element.content, sb); pattern = Pattern.compile(sb.toString()); patternCache.put(element, pattern); } return pattern; } void buildRegExp(final DTDItem item, final StringBuilder sb) { if (item instanceof DTDName) { sb.append("(,").append(((DTDName) item).value).append(")"); } else if (item instanceof DTDChoice) { sb.append("("); final DTDItem[] subItems = ((DTDChoice) item).getItem(); for (int i = 0; i < subItems.length; i++) { buildRegExp(subItems[i], sb); if (i < subItems.length - 1) sb.append("|"); } sb.append(")"); } else if (item instanceof DTDSequence) { sb.append("("); final DTDItem[] subItems = ((DTDSequence) item).getItem(); for (final DTDItem subItem : subItems) { buildRegExp(subItem, sb); } sb.append(")"); } else { throw new CompilerError(GenericErrors.GENERIC_ERROR, "Invalid DTD in extension point '" + id + "."); } if (item.cardinal == DTDCardinal.ONEMANY) { sb.append("+"); } else if (item.cardinal == DTDCardinal.ZEROMANY) { sb.append("*"); } else if (item.cardinal == DTDCardinal.OPTIONAL) { sb.append("?"); } } }