/*
 *  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
 *
 *      https://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.apache.tools.ant.taskdefs.optional.extension;

import java.io.File;
import java.util.List;
import java.util.Vector;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.FileSet;

Displays the "Optional Package" and "Package Specification" information
contained within the specified JARs.
Prior to JDK1.3, an "Optional Package" was known as an Extension.
The specification for this mechanism is available in the JDK1.3
documentation in the directory
$JDK_HOME/docs/guide/extensions/versioning.html. Alternatively it is
available online at 
https://docs.oracle.com/javase/8/docs/technotes/guides/extensions/versioning.html.
@ant.task
name="jarlib-display"/**
 * Displays the "Optional Package" and "Package Specification" information
 * contained within the specified JARs.
 *
 * <p>Prior to JDK1.3, an "Optional Package" was known as an Extension.
 * The specification for this mechanism is available in the JDK1.3
 * documentation in the directory
 * $JDK_HOME/docs/guide/extensions/versioning.html. Alternatively it is
 * available online at <a href="https://docs.oracle.com/javase/8/docs/technotes/guides/extensions/versioning.html">
 * https://docs.oracle.com/javase/8/docs/technotes/guides/extensions/versioning.html</a>.</p>
 *
 * @ant.task name="jarlib-display"
 */
public class JarLibDisplayTask extends Task {
    
The library to display information about.
/**
     * The library to display information about.
     */
    private File libraryFile;

    
Filesets specifying all the libraries
to display information about.
/**
     * Filesets specifying all the libraries
     * to display information about.
     */
    private final List<FileSet> libraryFileSets = new Vector<>();

    
The JAR library to display information for.
Params:
file – The jar library to display information for./**
     * The JAR library to display information for.
     *
     * @param file The jar library to display information for.
     */
    public void setFile(final File file) {
        this.libraryFile = file;
    }

    
Adds a set of files about which library data will be displayed.
Params:
fileSet – a set of files about which library data will be displayed./**
     * Adds a set of files about which library data will be displayed.
     *
     * @param fileSet a set of files about which library data will be displayed.
     */
    public void addFileset(final FileSet fileSet) {
        libraryFileSets.add(fileSet);
    }

    
Execute the task.
Throws:
BuildException – if the task fails./**
     * Execute the task.
     *
     * @throws BuildException if the task fails.
     */
    @Override
    public void execute() throws BuildException {
        validate();

        final LibraryDisplayer displayer = new LibraryDisplayer();
        // Check if list of files to check has been specified
        if (libraryFileSets.isEmpty()) {
            displayer.displayLibrary(libraryFile);
        } else {
            for (FileSet fileSet : libraryFileSets) {
                final DirectoryScanner scanner =
                    fileSet.getDirectoryScanner(getProject());
                final File basedir = scanner.getBasedir();
                for (String filename : scanner.getIncludedFiles()) {
                    displayer.displayLibrary(new File(basedir, filename));
                }
            }
        }
    }

    
Validate the tasks parameters.
Throws:
BuildException – if invalid parameters found/**
     * Validate the tasks parameters.
     *
     * @throws BuildException if invalid parameters found
     */
    private void validate() throws BuildException {
        if (null == libraryFile) {
            if (libraryFileSets.isEmpty()) {
                throw new BuildException("File attribute not specified.");
            }
        } else if (!libraryFile.exists()) {
            throw new BuildException("File '%s' does not exist.", libraryFile);
        } else if (!libraryFile.isFile()) {
            throw new BuildException("'%s' is not a file.", libraryFile);
        }
    }
}