trunk/jbi-api-1.0/src/main/java/javax/jbi/component/InstallationContext.java

/*
 * 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.
 */
package javax.jbi.component;

import org.w3c.dom.DocumentFragment;

/**
 * This context contains information necessary for a JBI component to perform
 * its installation/uninstallation processing.
 */
public interface InstallationContext {

    /**
     * Get the name of the class that implements the {@link Component}
     * interface for this component. This must be the component class name
     * given in the component's installation descriptor.
     *
     * @return the {@link Component} implementation class name, which
     *         must be non-null and non-empty.
     */
    String getComponentClassName();

    /**
     * Get a list of elements that comprise the class path for this component.
     * Each element represents either a directory (containing class files) or
     * a library file. All elements are reachable from the install root. These
     * elements represent class path items that the component's execution-time
     * component class loader uses, in search order. All path elements must use
     * the file separator character appropriate to the system (i.e.,
     * <code>File.separator</code>).
     * 
     * @return a list of String objects, each of which contains a class path
     *         elements. The list must contain at least one class path element.
     */
    java.util.List getClassPathElements();

    /**
     * Get the unique name assigned to this component. This name must be assigned
     * from the component's installation descriptor identification section.
     *
     * @return the unique component name, which must be non-null and non-empty.
     */
    String getComponentName();

    /**
     * Get the JBI context for this component. The following methods are valid
     * to use on the context:
     * <ul>
     *   <li>{@link ComponentContext#getLogger(String, String)}</li>
     *   <li>{@link ComponentContext#getMBeanNames()}</li>
     *   <li>{@link ComponentContext#getMBeanServer()}</li>
     *   <li>{@link ComponentContext#getNamingContext()}</li>
     *   <li>{@link ComponentContext#getTransactionManager()}</li>
     * </ul>
     *
     * All other methods on the returned context must throw a IllegalStateException
     * exception if invoked.
     *
     * @return the JBI context for this component, which must be non-null.
     */
    ComponentContext getContext();

    /**
     * Get the installation root directory full path name for this component.
     * This path name must be formatted for the platform the JBI environment
     * is running on.
     *
     * @return the installation root directory name, which must be non-null
     *         and non-empty.
     */
    String getInstallRoot();

    /**
     * Return a DOM document fragment representing the installation descriptor
     * (jbi.xml) extension data for the component, if any.
     *
     * The Installation Descriptor Extension data are located at the end of the
     * <component> element of the installation descriptor.
     *
     * @return a DOM document fragment containing the installation descriptor
     *         (jbi.xml) extension data, or null if none is present in the descriptor.
     */
    DocumentFragment getInstallationDescriptorExtension();

    /**
     * Returns <code>true</code> if this context was created in order to install a
     * component into the JBI environment. Returns false if this context was created
     * to uninstall a previously installed component.
     *
     * This method is provided to allow Bootstrap implementations to tailor their
     * behaviour according to use case. For example, the
     * {@link Bootstrap#init(InstallationContext)} method implementation may create
     * different types of extension MBeans, depending on the use case specified by
     * this method.
     *
     * @return <code>true</code> if this context was created in order to install a
     *         component into the JBI environment; otherwise the context was created
     *         to uninstall an existing component.
     */
    boolean isInstall();

    /**
     * Set the list of elements that comprise the class path for this component. Each
     * element represents either a directory (containing class files) or a library file.
     * Elements are reached from the install root. These elements represent class path
     * items that the component's execution-time component class loader uses, in search
     * order. All file paths are relative to the install root of the component.
     *
     * This method allows the component's bootstrap to alter the execution-time class
     * path specified by the component's installation descriptor. The component
     * configuration determined during installation can affect the class path needed by
     * the component at execution-time. All path elements must use the file separator
     * character appropriate to the system (i.e., <code>File.separator</code>).
     *
     * @param classPathElements a list of String objects, each of which contains a class
     *        path elements; the list must be non-null and contain at least one class path
     *        element.
     * @throws java.lang.IllegalArgumentException if the class path elements is null, empty,
     *                                            or if an individual element is ill-formed.
     */
    void setClassPathElements(java.util.List classPathElements);
}