Java tutorial
/* * Copyright (C) 2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.android.tools.internal.artifacts; import com.google.common.io.Closeables; import org.gradle.api.artifacts.ModuleIdentifier; import org.gradle.api.artifacts.ModuleVersionIdentifier; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; /** * Class able to parse a POM file, and provide some information from it: * - Is the artifact relocated (and what's the relocation artifact) * - parent POM * - packaging */ class PomHandler { private final File pomFile; private Document document = null; private final static class FakeModuleVersionIdentifier implements ModuleVersionIdentifier { private final String group; private final String name; private final String version; FakeModuleVersionIdentifier(String group, String name, String version) { this.group = group; this.name = name; this.version = version; } @Override public String getVersion() { return version; } @Override public String getGroup() { return group; } @Override public String getName() { return name; } @Override public ModuleIdentifier getModule() { throw new UnsupportedOperationException(); } @Override public String toString() { return getGroup() + ":" + getName() + ":" + getVersion(); } } PomHandler(File pomFile) { this.pomFile = pomFile; } ModuleVersionIdentifier getRelocation() throws IOException { Document document = getDocument(); Node rootNode = document.getDocumentElement(); Node node = findNode(rootNode, "distributionManagement"); if (node == null) { return null; } node = findNode(node, "relocation"); if (node == null) { return null; } // ok there is a relocation. Let's find out the current artifact address ModuleVersionIdentifier original = readArtifactAddress(rootNode); // now read the relocation info ModuleVersionIdentifier relocation = readArtifactAddress(node); // merge them in case only part of the address is changed return new FakeModuleVersionIdentifier( relocation.getGroup() != null ? relocation.getGroup() : original.getGroup(), relocation.getName() != null ? relocation.getName() : original.getName(), relocation.getVersion() != null ? relocation.getVersion() : original.getVersion()); } private ModuleVersionIdentifier readArtifactAddress(Node parentNode) { String group = null; String name = null; String version = null; Node node = findNode(parentNode, "groupId"); if (node != null) { group = getTextNode(node); } node = findNode(parentNode, "artifactId"); if (node != null) { name = getTextNode(node); } node = findNode(parentNode, "version"); if (node != null) { version = getTextNode(node); } return new FakeModuleVersionIdentifier(group, name, version); } ModuleVersionIdentifier getParentPom() throws IOException { Document document = getDocument(); Node rootNode = document.getDocumentElement(); Node node = findNode(rootNode, "parent"); if (node == null) { return null; } // there is a parent. Look for the rest of the nodes. final Node groupId = findNode(node, "groupId"); final Node artifactId = findNode(node, "artifactId"); final Node version = findNode(node, "version"); if (groupId == null || artifactId == null || version == null) { return null; } return new FakeModuleVersionIdentifier(getTextNode(groupId), getTextNode(artifactId), getTextNode(version)); } public String getPackaging() throws IOException { Document document = getDocument(); Node rootNode = document.getDocumentElement(); Node node = findNode(rootNode, "packaging"); if (node == null) { return null; } return getTextNode(node); } private Document getDocument() throws IOException { if (document == null) { document = parseDocument(pomFile); } return document; } private Node findNode(Node rootNode, String name) { NodeList nodes = rootNode.getChildNodes(); for (int i = 0, n = nodes.getLength(); i < n; i++) { Node node = nodes.item(i); if (node.getNodeType() != Node.ELEMENT_NODE) { continue; } if (name.equals(node.getLocalName())) { return node; } } return null; } private String getTextNode(Node rootNode) { NodeList nodes = rootNode.getChildNodes(); for (int i = 0, n = nodes.getLength(); i < n; i++) { Node node = nodes.item(i); if (node.getNodeType() != Node.TEXT_NODE) { continue; } return node.getNodeValue(); } return null; } /** * Loads the DOM for a given file and returns a {@link org.w3c.dom.Document} object. * @param file the file to parse * @return a Document object. * @throws java.io.IOException */ static Document parseDocument(File file) throws IOException { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); BufferedInputStream stream = new BufferedInputStream(new FileInputStream(file)); InputSource is = new InputSource(stream); factory.setNamespaceAware(true); factory.setValidating(false); try { DocumentBuilder builder = factory.newDocumentBuilder(); return builder.parse(is); } catch (ParserConfigurationException e) { throw new IOException(e); } catch (SAXException e) { throw new IOException(e); } finally { Closeables.close(stream, true /* swallowIOException */); } } }