Allow gradle builds without version numbers

Add a gradle `ResolutionStrategy` that resolves missing version numbers
using the `spring-boot-dependencies` POM.

This commit also introduces a new `spring-boot-dependency-tools` module
that provides programmatic access to the `dependencyManagement` section
of the dependencies POM.

Fixed gh-262

spring-boot-tools/spring-boot-dependency-tools/src/main/java/org/springframework/boot/dependency/tools/Assert.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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 org.springframework.boot.dependency.tools;
+
+/**
+ * Simple subset of the Spring Assert utility.
+ * 
+ * @author Phillip Webb
+ */
+class Assert {
+
+	public static void notNull(Object object, String message) {
+		if (object == null) {
+			throw new IllegalArgumentException(message);
+		}
+	}
+
+}

spring-boot-tools/spring-boot-dependency-tools/src/main/java/org/springframework/boot/dependency/tools/Dependency.java

@@ -0,0 +1,234 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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 org.springframework.boot.dependency.tools;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * A single managed dependency.
+ * 
+ * @author Phillip Webb
+ * @see ManagedDependencies
+ */
+public final class Dependency {
+
+	private final String groupId;
+
+	private final String artifactId;
+
+	private final String version;
+
+	private final List<Exclusion> exclusions;
+
+	/**
+	 * Create a new {@link Dependency} instance.
+	 * @param groupId the group ID
+	 * @param artifactId the artifact ID
+	 * @param version the version
+	 */
+	public Dependency(String groupId, String artifactId, String version) {
+		this(groupId, artifactId, version, Collections.<Exclusion> emptyList());
+	}
+
+	/**
+	 * Create a new {@link Dependency} instance.
+	 * @param groupId the group ID
+	 * @param artifactId the artifact ID
+	 * @param version the version
+	 * @param exclusions the exclusions
+	 */
+	public Dependency(String groupId, String artifactId, String version,
+			List<Exclusion> exclusions) {
+		Assert.notNull(groupId, "GroupId must not be null");
+		Assert.notNull(artifactId, "ArtifactId must not be null");
+		Assert.notNull(version, "Version must not be null");
+		Assert.notNull(exclusions, "Exclusions must not be null");
+		this.groupId = groupId;
+		this.artifactId = artifactId;
+		this.version = version;
+		this.exclusions = Collections.unmodifiableList(exclusions);
+	}
+
+	/**
+	 * Return the dependency group id.
+	 */
+	public String getGroupId() {
+		return this.groupId;
+	}
+
+	/**
+	 * Return the dependency artifact id.
+	 */
+	public String getArtifactId() {
+		return this.artifactId;
+	}
+
+	/**
+	 * Return the dependency version.
+	 */
+	public String getVersion() {
+		return this.version;
+	}
+
+	/**
+	 * Return the dependency exclusions.
+	 */
+	public List<Exclusion> getExclusions() {
+		return this.exclusions;
+	}
+
+	@Override
+	public String toString() {
+		return this.groupId + ":" + this.artifactId + ":" + this.version;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + this.groupId.hashCode();
+		result = prime * result + this.artifactId.hashCode();
+		result = prime * result + this.version.hashCode();
+		result = prime * result + this.exclusions.hashCode();
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() == obj.getClass()) {
+			Dependency other = (Dependency) obj;
+			boolean result = true;
+			result &= this.groupId.equals(other.groupId);
+			result &= this.artifactId.equals(other.artifactId);
+			result &= this.version.equals(other.version);
+			result &= this.exclusions.equals(other.exclusions);
+			return result;
+		}
+		return false;
+	}
+
+	static Dependency fromDependenciesXml(Element element) throws Exception {
+		String groupId = getTextContent(element, "groupId");
+		String artifactId = getTextContent(element, "artifactId");
+		String version = getTextContent(element, "version");
+		List<Exclusion> exclusions = Exclusion.fromExclusionsXml(element
+				.getElementsByTagName("exclusions"));
+		return new Dependency(groupId, artifactId, version, exclusions);
+	}
+
+	private static String getTextContent(Element element, String tagName) {
+		return element.getElementsByTagName(tagName).item(0).getTextContent();
+	}
+
+	/**
+	 * A dependency exclusion.
+	 */
+	public final static class Exclusion {
+
+		private final String groupId;
+
+		private final String artifactId;
+
+		private Exclusion(String groupId, String artifactId) {
+			Assert.notNull(groupId, "GroupId must not be null");
+			Assert.notNull(groupId, "ArtifactId must not be null");
+			this.groupId = groupId;
+			this.artifactId = artifactId;
+		}
+
+		/**
+		 * Return the exclusion artifact id.
+		 */
+		public String getArtifactId() {
+			return this.artifactId;
+		}
+
+		/**
+		 * Return the exclusion group id.
+		 */
+		public String getGroupId() {
+			return this.groupId;
+		}
+
+		@Override
+		public String toString() {
+			return this.groupId + ":" + this.artifactId;
+		}
+
+		@Override
+		public int hashCode() {
+			return this.groupId.hashCode() * 31 + this.artifactId.hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj == null) {
+				return false;
+			}
+			if (getClass() == obj.getClass()) {
+				Exclusion other = (Exclusion) obj;
+				boolean result = true;
+				result &= this.groupId.equals(other.groupId);
+				result &= this.artifactId.equals(other.artifactId);
+				return result;
+			}
+			return false;
+		}
+
+		private static List<Exclusion> fromExclusionsXml(NodeList exclusion) {
+			if (exclusion == null || exclusion.getLength() == 0) {
+				return Collections.emptyList();
+			}
+			return fromExclusionsXml(exclusion.item(0));
+		}
+
+		private static List<Exclusion> fromExclusionsXml(Node item) {
+			List<Exclusion> exclusions = new ArrayList<Dependency.Exclusion>();
+			NodeList children = item.getChildNodes();
+			for (int i = 0; i < children.getLength(); i++) {
+				Node child = children.item(i);
+				if (child instanceof Element) {
+					exclusions.add(fromExclusionXml((Element) child));
+				}
+			}
+			return exclusions;
+		}
+
+		private static Exclusion fromExclusionXml(Element element) {
+			String groupId = getTextContent(element, "groupId");
+			String artifactId = getTextContent(element, "artifactId");
+			return new Exclusion(groupId, artifactId);
+		}
+
+	}
+
+}

spring-boot-tools/spring-boot-dependency-tools/src/main/java/org/springframework/boot/dependency/tools/ManagedDependencies.java

@@ -0,0 +1,199 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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 org.springframework.boot.dependency.tools;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * Provides access to the managed dependencies declared in
+ * {@literal spring-boot-dependencies}.
+ * 
+ * @author Phillip Webb
+ * @see Dependency
+ */
+public class ManagedDependencies implements Iterable<Dependency> {
+
+	private static ManagedDependencies instance;
+
+	private final String version;
+
+	private final Map<ArtifactAndGroupId, Dependency> byArtifactAndGroupId;
+
+	private final Map<String, Dependency> byArtifactId;
+
+	ManagedDependencies(String dependenciesPomResource, String effectivePomResource) {
+		try {
+			Document dependenciesPomDocument = readDocument(dependenciesPomResource);
+			this.version = dependenciesPomDocument.getElementsByTagName("version")
+					.item(0).getTextContent();
+
+			// Parse all dependencies from the effective POM (with resolved properties)
+			Document effectivePomDocument = readDocument(effectivePomResource);
+			Map<ArtifactAndGroupId, Dependency> all = new HashMap<ArtifactAndGroupId, Dependency>();
+			for (Dependency dependency : readDependencies(effectivePomDocument)) {
+				all.put(new ArtifactAndGroupId(dependency), dependency);
+			}
+
+			// But only add those from the dependencies POM
+			this.byArtifactAndGroupId = new LinkedHashMap<ManagedDependencies.ArtifactAndGroupId, Dependency>();
+			this.byArtifactId = new LinkedHashMap<String, Dependency>();
+			for (Dependency dependency : readDependencies(dependenciesPomDocument)) {
+				ArtifactAndGroupId artifactAndGroupId = new ArtifactAndGroupId(dependency);
+				Dependency effectiveDependency = all.get(artifactAndGroupId);
+				if (effectiveDependency != null) {
+					this.byArtifactAndGroupId
+							.put(artifactAndGroupId, effectiveDependency);
+					this.byArtifactId.put(effectiveDependency.getArtifactId(),
+							effectiveDependency);
+				}
+			}
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+	private Document readDocument(String resource) throws Exception {
+		InputStream stream = getClass().getResourceAsStream(resource);
+		if (stream == null) {
+			throw new IllegalStateException("Unable to open resource " + resource);
+		}
+		DocumentBuilder documentBuilder = DocumentBuilderFactory.newInstance()
+				.newDocumentBuilder();
+		Document document = documentBuilder.parse(stream);
+		document.getDocumentElement().normalize();
+		return document;
+	}
+
+	private List<Dependency> readDependencies(Document document) throws Exception {
+		Element element = (Element) document.getElementsByTagName("project").item(0);
+		element = (Element) element.getElementsByTagName("dependencyManagement").item(0);
+		element = (Element) element.getElementsByTagName("dependencies").item(0);
+		NodeList nodes = element.getChildNodes();
+		List<Dependency> dependencies = new ArrayList<Dependency>();
+		for (int i = 0; i < nodes.getLength(); i++) {
+			Node node = nodes.item(i);
+			if (node instanceof Element) {
+				dependencies.add(Dependency.fromDependenciesXml((Element) node));
+			}
+		}
+		return dependencies;
+	}
+
+	/**
+	 * Return the 'spring-boot-dependencies' POM version.
+	 */
+	public String getVersion() {
+		return this.version;
+	}
+
+	/**
+	 * Find a single dependency for the given group and artifact IDs.
+	 * @param groupId the group ID
+	 * @param artifactId the artifact ID
+	 * @return a {@link Dependency} or {@code null}
+	 */
+	public Dependency find(String groupId, String artifactId) {
+		return this.byArtifactAndGroupId.get(new ArtifactAndGroupId(groupId, artifactId));
+	}
+
+	/**
+	 * Find a single dependency for the artifact IDs.
+	 * @param artifactId the artifact ID
+	 * @return a {@link Dependency} or {@code null}
+	 */
+	public Dependency find(String artifactId) {
+		return this.byArtifactId.get(artifactId);
+	}
+
+	/**
+	 * Provide an {@link Iterator} over all managed {@link Dependency Dependencies}.
+	 */
+	@Override
+	public Iterator<Dependency> iterator() {
+		return this.byArtifactAndGroupId.values().iterator();
+	}
+
+	/**
+	 * @return The Spring Boot managed dependencies.
+	 */
+	public static ManagedDependencies get() {
+		if (instance == null) {
+			return new ManagedDependencies("dependencies-pom.xml", "effective-pom.xml");
+		}
+		return instance;
+	}
+
+	/**
+	 * Simple holder for an artifact+group ID.
+	 */
+	private static class ArtifactAndGroupId {
+
+		private final String groupId;
+
+		private final String artifactId;
+
+		public ArtifactAndGroupId(Dependency dependency) {
+			this(dependency.getGroupId(), dependency.getArtifactId());
+		}
+
+		public ArtifactAndGroupId(String groupId, String artifactId) {
+			Assert.notNull(groupId, "GroupId must not be null");
+			Assert.notNull(artifactId, "ArtifactId must not be null");
+			this.groupId = groupId;
+			this.artifactId = artifactId;
+		}
+
+		@Override
+		public int hashCode() {
+			return this.groupId.hashCode() * 31 + this.artifactId.hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj == null) {
+				return false;
+			}
+			if (getClass() == obj.getClass()) {
+				ArtifactAndGroupId other = (ArtifactAndGroupId) obj;
+				boolean result = true;
+				result &= this.groupId.equals(other.groupId);
+				result &= this.artifactId.equals(other.artifactId);
+				return result;
+			}
+			return false;
+		}
+
+	}
+}

spring-boot-tools/spring-boot-dependency-tools/src/main/java/org/springframework/boot/dependency/tools/package-info.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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.
+ */
+
+/**
+ * Utilities for working with the managed dependencies declared in the
+ * {@literal spring-boot-dependencies} project.
+ *
+ * @see org.springframework.boot.dependency.tools.ManagedDependencies
+ */
+package org.springframework.boot.dependency.tools;
+

spring-boot-tools/spring-boot-dependency-tools/src/test/java/org/springframework/boot/dependency/tools/ManagedDependenciesTests.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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 org.springframework.boot.dependency.tools;
+
+import java.util.Iterator;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link ManagedDependencies}.
+ * 
+ * @author Phillip Webb
+ */
+public class ManagedDependenciesTests {
+
+	private ManagedDependencies dependencies;
+
+	@Before
+	public void setup() {
+		this.dependencies = new ManagedDependencies("test-dependencies-pom.xml",
+				"test-effective-pom.xml");
+	}
+
+	@Test
+	public void version() throws Exception {
+		assertThat(this.dependencies.getVersion(), equalTo("1.0.0.BUILD-SNAPSHOT"));
+	}
+
+	@Test
+	public void iterate() throws Exception {
+		Iterator<Dependency> iterator = this.dependencies.iterator();
+		assertThat(iterator.next().toString(), equalTo("org.sample:sample01:1.0.0"));
+		assertThat(iterator.next().toString(), equalTo("org.sample:sample02:1.0.0"));
+		assertThat(iterator.hasNext(), equalTo(false));
+	}
+
+	@Test
+	public void findByArtifactAndGroupId() throws Exception {
+		assertThat(this.dependencies.find("org.sample", "sample02").toString(),
+				equalTo("org.sample:sample02:1.0.0"));
+	}
+
+	@Test
+	public void findByArtifactAndGroupIdMissing() throws Exception {
+		assertThat(this.dependencies.find("org.sample", "missing"), nullValue());
+	}
+
+	@Test
+	public void findByArtifactAndGroupIdOnlyInEffectivePom() throws Exception {
+		assertThat(this.dependencies.find("org.extra", "extra01"), nullValue());
+	}
+
+	@Test
+	public void findByArtifactId() throws Exception {
+		assertThat(this.dependencies.find("sample02").toString(),
+				equalTo("org.sample:sample02:1.0.0"));
+	}
+
+	@Test
+	public void findByArtifactIdMissing() throws Exception {
+		assertThat(this.dependencies.find("missing"), nullValue());
+	}
+
+	@Test
+	public void exludes() throws Exception {
+		Dependency dependency = this.dependencies.find("org.sample", "sample01");
+		assertThat(dependency.getExclusions().toString(),
+				equalTo("[org.exclude:exclude01]"));
+	}
+
+	@Test
+	public void get() throws Exception {
+		ManagedDependencies dependencies = ManagedDependencies.get();
+		assertThat(dependencies.iterator().hasNext(), equalTo(true));
+		assertThat(dependencies.find("org.springframework", "spring-core"),
+				notNullValue());
+	}
+
+}

spring-boot-tools/spring-boot-dependency-tools/src/test/resources/org/springframework/boot/dependency/tools/test-dependencies-pom.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project>
+	<modelVersion>4.0.0</modelVersion>
+	<version>1.0.0.BUILD-SNAPSHOT</version>
+	<properties>
+		<sample.version>1.0.0</sample.version>
+	</properties>
+	<prerequisites>
+		<maven>3.0.0</maven>
+	</prerequisites>
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>org.sample</groupId>
+				<artifactId>sample01</artifactId>
+				<version>${sample.version}</version>
+				<exclusions>
+                    <exclusion>
+                        <groupId>org.exclude</groupId>
+                        <artifactId>exclude01</artifactId>
+                    </exclusion>
+				</exclusions>
+			</dependency>
+			<dependency>
+				<groupId>org.sample</groupId>
+				<artifactId>sample02</artifactId>
+				<version>${sample.version}</version>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+</project>

spring-boot-tools/spring-boot-dependency-tools/src/test/resources/org/springframework/boot/dependency/tools/test-effective-pom.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<version>1.0.0.BUILD-SNAPSHOT</version>
+	<properties>
+		<sample.version>1.0.0</sample.version>
+	</properties>
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>org.sample</groupId>
+				<artifactId>sample01</artifactId>
+				<version>1.0.0</version>
+				<exclusions>
+					<exclusion>
+						<groupId>org.exclude</groupId>
+						<artifactId>exclude01</artifactId>
+					</exclusion>
+				</exclusions>
+			</dependency>
+			<dependency>
+				<groupId>org.sample</groupId>
+				<artifactId>sample02</artifactId>
+				<version>1.0.0</version>
+			</dependency>
+			<dependency>
+				<groupId>org.extra</groupId>
+				<artifactId>extra01</artifactId>
+				<version>2.0.0</version>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+</project>