Adding content interfaces to repository api
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Artifact.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Artifact.java
new file mode 100644
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--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Artifact.java
@@ -0,0 +1,175 @@
+package org.apache.archiva.repository.content;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.UnsupportedRepositoryTypeException;
+import org.apache.archiva.repository.storage.StorageAsset;
+
+import java.util.Map;
+
+/**
+ *
+ * Represents a artifact of a repository. This object contains unique coordinates of the
+ * artifact. A artifact has exactly one file representation in the repository.
+ * The artifact instance does not tell, if the file exists or is readable. It just
+ * keeps the coordinates and some meta information of the artifact.
+ *
+ * Artifact implementations should be immutable. The implementation must not always represent the current state of the
+ * corresponding storage asset (file). It is just a view of the attributes for a given point in time.
+ *
+ * Implementations must provide proper hash and equals methods.
+ *
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface Artifact extends Comparable<Artifact>
+{
+ /**
+ * The namespace is the location of the artifact.
+ * E.g. for maven artifacts it is the groupId.
+ * The namespace may be empty. Which means that is the base or root namespace.
+ *
+ * @return the namespace of the artifact. Never returns <code>null</code>.
+ */
+ String getNamespace();
+
+ /**
+ * The artifact identifier. The ID is unique in a given namespace of a given repository.
+ * But there may exist artifacts with the same ID but different types, classifiers or extensions.
+ *
+ * Never returns <code>null</code> or a empty string.
+ *
+ * @return the identifier of the artifact. Never returns <code>null</code> or empty string
+ */
+ String getId();
+
+ /**
+ * The version string of the artifact. The version string is exactly the version that is attached
+ * to the artifact.
+ * The version string may be different to the version string returned by the attached {@link Version} object.
+ * E.g for maven artifacts the artifact version may be 1.3-20070725.210059-1 and the attached {@link Version} object
+ * has version 1.3-SNAPSHOT.
+ *
+ * @return the artifact version string
+ * @see #getVersion()
+ */
+ String getArtifactVersion();
+
+ /**
+ * Returns the attached version this artifact is part of.
+ * @return the version object
+ */
+ Version getVersion();
+
+ /**
+ * Returns the project this artifact is part of.
+ * @return the project object
+ */
+ Project getProject();
+
+ /**
+ * Returns the type of the artifact. The type is some hint about the usage of the artifact.
+ * Implementations may always return a empty string, if it is not used.
+ *
+ * @return the type of the artifact. Returns never <code>null</code>, but may be empty string
+ */
+ String getType();
+
+ /**
+ * A classifier that distinguishes artifacts.
+ * Implementations may always return a empty string, if it is not used.
+ *
+ * @return the classifier of the artifact. Returns never <code>null</code>, but may be empty string
+ */
+ String getClassifier();
+
+ /**
+ * Short cut for the file name. Should always return the same value as the artifact name.
+ * @return the name of the file
+ */
+ default String getFileName() {
+ return getAsset( ).getName( );
+ }
+
+ /**
+ * Returns the extension of the file. This method should always return the extension string after the last
+ * '.'-character.
+ *
+ * @return the file name extension
+ */
+ default String getExtension() {
+ final String name = getAsset().getName();
+ final int idx = name.lastIndexOf( '.' );
+ if (idx>=0) {
+ return name.substring( idx );
+ } else {
+ return "";
+ }
+ }
+
+ /**
+ * This may be different from extension and gives the remainder that is used to build the file path from
+ * the artifact coordinates (namespace, id, version, classifier, type)
+ *
+ * @return the file name remainder
+ */
+ String getRemainder();
+
+ /**
+ * Should return the mime type of the artifact.
+ *
+ * @return the mime type of the artifact.
+ */
+ String getContentType();
+
+ /**
+ * Returns the storage representation of the artifact. The asset must not exist.
+ *
+ * @return the asset this artifact corresponds to.
+ */
+ StorageAsset getAsset();
+
+ /**
+ * Returns additional attributes of the artifact. Implementations may add additional attributes, e.g. author name
+ * or creation date. Specific implementation attributes can be accessed either by the {@link #getAttributes()} method
+ * or by a specific implementation class (see {@link #adapt(Class)}. Use via the adapter is type safe.
+ *
+ * @return a map of attribute key, value pairs
+ */
+ Map<String,String> getAttributes();
+
+
+ /**
+ * Returns the repository type specific implementation
+ * @param clazz the specific implementation class
+ * @param <T> the class or interface
+ * @return the specific project implementation
+ */
+ <T extends Artifact> T adapt(Class<T> clazz) throws UnsupportedRepositoryTypeException;
+
+ /**
+ * Returns <code>true</code>, if this project supports the given adaptor class.
+ * @param clazz the class to convert this project to
+ * @param <T> the type
+ * @return <code>true/code>, if the implementation is supported, otherwise false
+ */
+ <T extends Artifact> boolean supports(Class<T> clazz);
+
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Project.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Project.java
new file mode 100644
index 0000000..d52339d
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Project.java
@@ -0,0 +1,85 @@
+package org.apache.archiva.repository.content;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.RepositoryContent;
+import org.apache.archiva.repository.UnsupportedRepositoryTypeException;
+
+import java.util.Map;
+
+/**
+ *
+ * The project is the container for several versions each with different artifacts.
+ *
+ * <pre>
+ * project +--> version 1 + -> artifact 1
+ * | |
+ * | + -> artifact 2
+ * |
+ * +--> version 2 ----> artifact 3
+ * </pre>
+ *
+ * Implementations must provide proper hash and equals methods.
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface Project extends Comparable<Project>
+{
+
+ /**
+ * The namespace of the project
+ * @return the namespace
+ */
+ String getNamespace();
+
+ /**
+ * The id of the project
+ * @return the project id
+ */
+ String getId();
+
+ /**
+ * The repository this project is part of.
+ * @return the repository content
+ */
+ RepositoryContent getRepository();
+
+ /**
+ * Additional attributes
+ * @return the additional attributes
+ */
+ Map<String, String> getAttributes();
+
+ /**
+ * Returns the repository type specific implementation
+ * @param clazz the specific implementation class
+ * @param <T> the class or interface
+ * @return the specific project implementation
+ */
+ <T extends Project> T adapt(Class<T> clazz) throws UnsupportedRepositoryTypeException;
+
+ /**
+ * Returns <code>true</code>, if this project supports the given adaptor class.
+ * @param clazz the class to convert this project to
+ * @param <T> the type
+ * @return <code>true/code>, if the implementation is supported, otherwise false
+ */
+ <T extends Project> boolean supports(Class<T> clazz);
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Version.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Version.java
new file mode 100644
index 0000000..6c17dee
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/content/Version.java
@@ -0,0 +1,80 @@
+package org.apache.archiva.repository.content;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.UnsupportedRepositoryTypeException;
+import org.apache.archiva.repository.storage.StorageAsset;
+
+import java.util.Map;
+
+/**
+ *
+ * Each artifact is attached to exactly one version.
+ *
+ * Implementations must provide proper hash and equals methods.
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface Version extends Comparable<Version>
+{
+ /**
+ * Returns the version string.
+ *
+ * @return the version string
+ */
+ String getVersion();
+
+ /**
+ * Returns the local representation of the version. For maven this is a directory.
+ * It is implementation dependent, what exactly this asset points to.
+ *
+ * @return the local storage representation of the version
+ */
+ StorageAsset getAsset();
+
+ /**
+ * Each version is attached to a project.
+ * @return the attached project
+ */
+ Project getProject();
+
+ /**
+ * Returns additional attributes.
+ * @return the map of attribute key, value pairs
+ */
+ Map<String,String> getAttributes();
+
+ /**
+ * Returns the repository type specific implementation
+ * @param clazz the specific implementation class
+ * @param <T> the class or interface
+ * @return the specific project implementation
+ */
+ <T extends Project> T adapt(Class<T> clazz) throws UnsupportedRepositoryTypeException;
+
+ /**
+ * Returns <code>true</code>, if this project supports the given adaptor class.
+ * @param clazz the class to convert this project to
+ * @param <T> the type
+ * @return <code>true/code>, if the implementation is supported, otherwise false
+ */
+ <T extends Project> boolean supports(Class<T> clazz);
+
+}
