org.springframework.boot.ResourceBanner.java Source code

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Here is the source code for org.springframework.boot.ResourceBanner.java

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/*
 * Copyright 2012-2019 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
 *
 *      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.springframework.boot;

import java.io.PrintStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.boot.ansi.AnsiPropertySource;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertyResolver;
import org.springframework.core.env.PropertySourcesPropertyResolver;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
import org.springframework.util.StreamUtils;

/**
 * Banner implementation that prints from a source text {@link Resource}.
 *
 * @author Phillip Webb
 * @author Vedran Pavic
 * @since 1.2.0
 */
public class ResourceBanner implements Banner {

    private static final Log logger = LogFactory.getLog(ResourceBanner.class);

    private Resource resource;

    public ResourceBanner(Resource resource) {
        Assert.notNull(resource, "Resource must not be null");
        Assert.isTrue(resource.exists(), "Resource must exist");
        this.resource = resource;
    }

    @Override
    public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
        try {
            String banner = StreamUtils.copyToString(this.resource.getInputStream(),
                    environment.getProperty("spring.banner.charset", Charset.class, StandardCharsets.UTF_8));

            for (PropertyResolver resolver : getPropertyResolvers(environment, sourceClass)) {
                banner = resolver.resolvePlaceholders(banner);
            }
            out.println(banner);
        } catch (Exception ex) {
            logger.warn("Banner not printable: " + this.resource + " (" + ex.getClass() + ": '" + ex.getMessage()
                    + "')", ex);
        }
    }

    protected List<PropertyResolver> getPropertyResolvers(Environment environment, Class<?> sourceClass) {
        List<PropertyResolver> resolvers = new ArrayList<>();
        resolvers.add(environment);
        resolvers.add(getVersionResolver(sourceClass));
        resolvers.add(getAnsiResolver());
        resolvers.add(getTitleResolver(sourceClass));
        return resolvers;
    }

    private PropertyResolver getVersionResolver(Class<?> sourceClass) {
        MutablePropertySources propertySources = new MutablePropertySources();
        propertySources.addLast(new MapPropertySource("version", getVersionsMap(sourceClass)));
        return new PropertySourcesPropertyResolver(propertySources);
    }

    private Map<String, Object> getVersionsMap(Class<?> sourceClass) {
        String appVersion = getApplicationVersion(sourceClass);
        String bootVersion = getBootVersion();
        Map<String, Object> versions = new HashMap<>();
        versions.put("application.version", getVersionString(appVersion, false));
        versions.put("spring-boot.version", getVersionString(bootVersion, false));
        versions.put("application.formatted-version", getVersionString(appVersion, true));
        versions.put("spring-boot.formatted-version", getVersionString(bootVersion, true));
        return versions;
    }

    protected String getApplicationVersion(Class<?> sourceClass) {
        Package sourcePackage = (sourceClass != null) ? sourceClass.getPackage() : null;
        return (sourcePackage != null) ? sourcePackage.getImplementationVersion() : null;
    }

    protected String getBootVersion() {
        return SpringBootVersion.getVersion();
    }

    private String getVersionString(String version, boolean format) {
        if (version == null) {
            return "";
        }
        return format ? " (v" + version + ")" : version;
    }

    private PropertyResolver getAnsiResolver() {
        MutablePropertySources sources = new MutablePropertySources();
        sources.addFirst(new AnsiPropertySource("ansi", true));
        return new PropertySourcesPropertyResolver(sources);
    }

    private PropertyResolver getTitleResolver(Class<?> sourceClass) {
        MutablePropertySources sources = new MutablePropertySources();
        String applicationTitle = getApplicationTitle(sourceClass);
        Map<String, Object> titleMap = Collections.singletonMap("application.title",
                (applicationTitle != null) ? applicationTitle : "");
        sources.addFirst(new MapPropertySource("title", titleMap));
        return new PropertySourcesPropertyResolver(sources);
    }

    protected String getApplicationTitle(Class<?> sourceClass) {
        Package sourcePackage = (sourceClass != null) ? sourceClass.getPackage() : null;
        return (sourcePackage != null) ? sourcePackage.getImplementationTitle() : null;
    }

}