src/main/java/org/apache/maven/shared/jar/identification/JarIdentificationAnalysis.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 org.apache.maven.shared.jar.identification;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.util.List;

import org.apache.maven.shared.jar.JarAnalyzer;
import org.codehaus.plexus.util.StringUtils;

import static java.util.Objects.requireNonNull;

/**
 * Analyze the JAR file to identify Maven artifact metadata. This class is thread safe and immutable as long as all
 * provided exposers are, as it retains no state.
 *
 * If using Plexus, the class will use all available exposers in the container.
 *
 * Note that you must first create an instance of {@link org.apache.maven.shared.jar.JarAnalyzer} - see its Javadoc for
 * a typical use.
 */
@Singleton
@Named
public class JarIdentificationAnalysis {
    /**
     * The Maven information exposers to use during identification.
     */
    private final List<JarIdentificationExposer> exposers;

    @Inject
    public JarIdentificationAnalysis(List<JarIdentificationExposer> exposers) {
        this.exposers = requireNonNull(exposers);
    }

    /**
     * Analyze a JAR and find any associated Maven metadata. Note that if the provided JAR analyzer has previously
     * analyzed the JAR, the cached results will be returned. You must obtain a new JAR analyzer to the re-read the
     * contents of the file.
     *
     * @param jarAnalyzer the JAR to analyze. This must not yet have been closed.
     * @return the Maven metadata discovered
     */
    public JarIdentification analyze(JarAnalyzer jarAnalyzer) {
        JarIdentification taxon = jarAnalyzer.getJarData().getJarIdentification();
        if (taxon != null) {
            return taxon;
        }

        taxon = new JarIdentification();

        for (JarIdentificationExposer exposer : exposers) {
            exposer.expose(taxon, jarAnalyzer);
        }

        normalize(taxon);

        jarAnalyzer.getJarData().setJarIdentification(taxon);

        return taxon;
    }

    private void normalize(JarIdentification taxon) {
        if (StringUtils.isEmpty(taxon.getGroupId())) {
            taxon.setGroupId(pickSmallest(taxon.getPotentialGroupIds()));
        }

        if (StringUtils.isEmpty(taxon.getArtifactId())) {
            taxon.setArtifactId(pickLargest(taxon.getPotentialArtifactIds()));
        }

        if (StringUtils.isEmpty(taxon.getVersion())) {
            taxon.setVersion(pickSmallest(taxon.getPotentialVersions()));
        }

        if (StringUtils.isEmpty(taxon.getName())) {
            taxon.setName(pickLargest(taxon.getPotentialNames()));
        }

        if (StringUtils.isEmpty(taxon.getVendor())) {
            taxon.setVendor(pickLargest(taxon.getPotentialVendors()));
        }
    }

    private String pickSmallest(List<String> list) {
        String smallest = null;

        int size = Integer.MAX_VALUE;
        for (String val : list) {
            if (val != null && !val.isEmpty()) {
                if (val.length() < size) {
                    smallest = val;
                    size = val.length();
                }
            }
        }

        return smallest;
    }

    private String pickLargest(List<String> list) {
        String largest = null;
        int size = Integer.MIN_VALUE;
        for (String val : list) {
            if (val != null && !val.isEmpty()) {
                if (val.length() > size) {
                    largest = val;
                    size = val.length();
                }
            }
        }
        return largest;
    }
}