org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor.java Source code

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Here is the source code for org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor.java

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/*
 * Copyright 2012-2015 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 org.springframework.boot.env;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;

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

import org.springframework.boot.SpringApplication;
import org.springframework.boot.json.JsonParser;
import org.springframework.boot.json.JsonParserFactory;
import org.springframework.core.Ordered;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.StandardEnvironment;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.support.StandardServletEnvironment;

/**
 * An {@link EnvironmentPostProcessor} that parses JSON from
 * {@code spring.application.json} or equivalently
 * {@link SpringApplicationJsonEnvironmentPostProcessor} and adds it as a map property
 * source to the {@link Environment}. The new properties are added with higher priority
 * than the system properties.
 *
 * @author Dave Syer
 * @author Phillip Webb
 * @since 1.3.0
 */
public class SpringApplicationJsonEnvironmentPostProcessor implements EnvironmentPostProcessor, Ordered {

    private static final String SERVLET_ENVIRONMENT_CLASS = "org.springframework.web."
            + "context.support.StandardServletEnvironment";

    /**
     * The default order for the processor.
     */
    public static final int DEFAULT_ORDER = Ordered.HIGHEST_PRECEDENCE + 5;

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

    private int order = DEFAULT_ORDER;

    @Override
    public int getOrder() {
        return this.order;
    }

    public void setOrder(int order) {
        this.order = order;
    }

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
        String json = environment.resolvePlaceholders("${spring.application.json:${SPRING_APPLICATION_JSON:}}");
        if (StringUtils.hasText(json)) {
            processJson(environment, json);
        }
    }

    private void processJson(ConfigurableEnvironment environment, String json) {
        try {
            JsonParser parser = JsonParserFactory.getJsonParser();
            Map<String, Object> map = parser.parseMap(json);
            if (!map.isEmpty()) {
                addJsonPropertySource(environment, new MapPropertySource("spring.application.json", flatten(map)));
            }
        } catch (Exception ex) {
            logger.warn("Cannot parse JSON for spring.application.json: " + json, ex);
        }
    }

    /**
     * Flatten the map keys using period separator.
     * @param map The map that should be flattened
     * @return the flattened map
     */
    private Map<String, Object> flatten(Map<String, Object> map) {
        Map<String, Object> result = new LinkedHashMap<String, Object>();
        flatten(null, result, map);
        return result;
    }

    private void flatten(String prefix, Map<String, Object> result, Map<String, Object> map) {
        prefix = (prefix == null ? "" : prefix + ".");
        for (Map.Entry<String, Object> entry : map.entrySet()) {
            extract(prefix + entry.getKey(), result, entry.getValue());
        }
    }

    @SuppressWarnings("unchecked")
    private void extract(String name, Map<String, Object> result, Object value) {
        if (value instanceof Map) {
            flatten(name, result, (Map<String, Object>) value);
        } else if (value instanceof Collection) {
            int index = 0;
            for (Object object : (Collection<Object>) value) {
                extract(name + "[" + index + "]", result, object);
                index++;
            }
        } else {
            result.put(name, value);
        }
    }

    private void addJsonPropertySource(ConfigurableEnvironment environment, PropertySource<?> source) {
        MutablePropertySources sources = environment.getPropertySources();
        String name = findPropertySource(sources);
        if (sources.contains(name)) {
            sources.addBefore(name, source);
        } else {
            sources.addFirst(source);
        }
    }

    private String findPropertySource(MutablePropertySources sources) {
        if (ClassUtils.isPresent(SERVLET_ENVIRONMENT_CLASS, null)
                && sources.contains(StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME)) {
            return StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME;

        }
        return StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME;
    }

}