io.joshworks.snappy.maven.PropertiesMergingResourceTransformer Maven / Gradle / Ivy

Go to download
/*
 * Copyright 2012-2016 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 io.joshworks.snappy.maven;

import org.apache.maven.plugins.shade.relocation.Relocator;
import org.apache.maven.plugins.shade.resource.ResourceTransformer;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;

/**
 * Extension for the Maven
 * shade plugin to allow properties files (e.g. {@literal META-INF/spring.factories})
 * to be merged without losing any information.
 *
 * @author Dave Syer
 * @author Andy Wilkinson
 */
public class PropertiesMergingResourceTransformer implements ResourceTransformer {

    private final Properties data = new Properties();
    // Set this in pom configuration with ...
    private String resource;

    /**
     * Return the data the properties being merged.
     *
     * @return the data
     */
    public Properties getData() {
        return this.data;
    }

    @Override
    public boolean canTransformResource(String resource) {
        if (this.resource != null && this.resource.equalsIgnoreCase(resource)) {
            return true;
        }
        return false;
    }

    @Override
    public void processResource(String resource, InputStream is,
                                List relocators) throws IOException {
        Properties properties = new Properties();
        properties.load(is);
        is.close();
        for (Entry entry : properties.entrySet()) {
            String name = (String) entry.getKey();
            String value = (String) entry.getValue();
            String existing = this.data.getProperty(name);
            this.data.setProperty(name,
                    existing == null ? value : existing + "," + value);
        }
    }

    @Override
    public boolean hasTransformedResource() {
        return !this.data.isEmpty();
    }

    @Override
    public void modifyOutputStream(JarOutputStream os) throws IOException {
        os.putNextEntry(new JarEntry(this.resource));
        this.data.store(os, "Merged by PropertiesMergingResourceTransformer");
        os.flush();
        this.data.clear();
    }

    public String getResource() {
        return this.resource;
    }

    public void setResource(String resource) {
        this.resource = resource;
    }

}