org.springframework.boot.context.config.RandomValuePropertySource.java Source code

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Here is the source code for org.springframework.boot.context.config.RandomValuePropertySource.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.context.config;

import java.util.Random;

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

import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.StandardEnvironment;
import org.springframework.util.DigestUtils;
import org.springframework.util.StringUtils;

/**
 * {@link PropertySource} that returns a random value for any property that starts with
 * {@literal "random."}. Where the "unqualified property name" is the portion of the
 * requested property name beyond the "random." prefix, this {@link PropertySource}
 * returns:
 * <ul>
 * <li>When {@literal "int"}, a random {@link Integer} value, restricted by an optionally
 * specified range.</li>
 * <li>When {@literal "long"}, a random {@link Long} value, restricted by an optionally
 * specified range.</li>
 * <li>Otherwise, a {@code byte[]}.</li>
 * </ul>
 * The {@literal "random.int"} and {@literal "random.long"} properties supports a range
 * suffix whose syntax is:
 * <p>
 * {@code OPEN value (,max) CLOSE} where the {@code OPEN,CLOSE} are any character and
 * {@code value,max} are integers. If {@code max} is provided then {@code value} is the
 * minimum value and {@code max} is the maximum (exclusive).
 *
 * @author Dave Syer
 * @author Matt Benson
 */
public class RandomValuePropertySource extends PropertySource<Random> {

    private static final String PREFIX = "random.";

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

    public RandomValuePropertySource(String name) {
        super(name, new Random());
    }

    @Override
    public Object getProperty(String name) {
        if (!name.startsWith(PREFIX)) {
            return null;
        }
        if (logger.isTraceEnabled()) {
            logger.trace("Generating random property for '" + name + "'");
        }
        return getRandomValue(name.substring(PREFIX.length()));
    }

    private Object getRandomValue(String type) {
        if (type.equals("int")) {
            return getSource().nextInt();
        }
        if (type.equals("long")) {
            return getSource().nextLong();
        }
        String range = getRange(type, "int");
        if (range != null) {
            return getNextIntInRange(range);
        }
        range = getRange(type, "long");
        if (range != null) {
            return getNextLongInRange(range);
        }
        return getRandomBytes();
    }

    private String getRange(String type, String prefix) {
        if (type.startsWith(prefix)) {
            int startIndex = prefix.length() + 1;
            if (type.length() > startIndex) {
                return type.substring(startIndex, type.length() - 1);
            }
        }
        return null;
    }

    private int getNextIntInRange(String range) {
        String[] tokens = StringUtils.commaDelimitedListToStringArray(range);
        int start = Integer.parseInt(tokens[0]);
        if (tokens.length == 1) {
            return getSource().nextInt(start);
        }
        return start + getSource().nextInt(Integer.parseInt(tokens[1]) - start);
    }

    private long getNextLongInRange(String range) {
        String[] tokens = StringUtils.commaDelimitedListToStringArray(range);
        if (tokens.length == 1) {
            return Math.abs(getSource().nextLong()) % Long.parseLong(tokens[0]);
        }
        long lowerBound = Long.parseLong(tokens[0]);
        long upperBound = Long.parseLong(tokens[1]) - lowerBound;
        return lowerBound + Math.abs(getSource().nextLong()) % upperBound;
    }

    private Object getRandomBytes() {
        byte[] bytes = new byte[32];
        getSource().nextBytes(bytes);
        return DigestUtils.md5DigestAsHex(bytes);
    }

    public static void addToEnvironment(ConfigurableEnvironment environment) {
        environment.getPropertySources().addAfter(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
                new RandomValuePropertySource("random"));
        logger.trace("RandomValuePropertySource add to Environment");
    }

}