com.prowidesoftware.deprecation.DeprecationUtils.java Source code

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Here is the source code for com.prowidesoftware.deprecation.DeprecationUtils.java

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/*******************************************************************************
 * Copyright (c) 2016 Prowide Inc.
 *
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU Lesser General Public License as 
 *     published by the Free Software Foundation, either version 3 of the 
 *     License, or (at your option) any later version.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 *     
 *     Check the LGPL at <http://www.gnu.org/licenses/> for more details.
 *******************************************************************************/
package com.prowidesoftware.deprecation;

import java.lang.reflect.Field;
import java.util.Collections;
import java.util.Map;
import java.util.logging.Level;

import org.apache.commons.lang.StringUtils;

/**
 * Helper API to implement the http://www.prowidesoftware.com/resources/deprecation-policy
 * 
 * @author sebastian
 * @since 7.8.9
 */
public class DeprecationUtils {
    private static final transient java.util.logging.Logger log = java.util.logging.Logger
            .getLogger(DeprecationUtils.class.getName());

    /**
     * Environment variable used to switch off deprecation phase implementation
     */
    public static final String PW_DEPRECATED = "PW_DEPRECATED";

    // Suppress default constructor for noninstantiability
    private DeprecationUtils() {
        throw new AssertionError();
    }

    /**
     * According to the deprecation policy this method implements the phase 2 which 
     * involves logging a warning and making a small pause in the execution thread.
     * @param message the log message
     */
    @SuppressWarnings("rawtypes")
    public static void phase2(final Class clazz, final String method, final String message) {
        if (!isSet(EnvironmentVariableKey.NOLOG)) {
            log.warning(notice(clazz, method) + message);
        }
        if (!isSet(EnvironmentVariableKey.NODELAY)) {
            try {
                Thread.sleep(4000);
            } catch (InterruptedException e) {
                log.log(Level.WARNING, notice(clazz, method) + message, e);
                ;
            }
        }
    }

    @SuppressWarnings("rawtypes")
    private static String notice(final Class clazz, final String method) {
        StringBuilder note = new StringBuilder();
        note.append("The API ").append(clazz.getSimpleName());
        if (method != null) {
            note.append("#").append(method);
        }
        note.append(" is deprecated. ");
        return note.toString();
    }

    /**
     * According to the deprecation policy this method implements the phase 3 which 
     * involves throwing a runtime exception.
     * @param message the log message
     */
    @SuppressWarnings("rawtypes")
    public static void phase3(final Class clazz, final String method, final String message) {
        if (!isSet(EnvironmentVariableKey.NOEXCEPTION)) {
            throw new UnsupportedOperationException(notice(clazz, method) + message);
        } else {
            /*
             * fall back to phase 2
             */
            phase2(clazz, method, message);
        }
    }

    /**
     * Returns true if the environment variable {@link #PW_DEPRECATED} contains
     * the given key in its value
     */
    private static final boolean isSet(final EnvironmentVariableKey key) {
        return StringUtils.containsIgnoreCase(System.getenv(PW_DEPRECATED), key.name());
    }

    /**
     * Keywords for the environment variable {@link #PW_DEPRECATED}
     */
    public enum EnvironmentVariableKey {
        NOLOG, NODELAY, NOEXCEPTION
    }

    /**
     * Helper hack to set the environment variable from Java.
     * 
     * <p>For example if all keys are passed as parameter, this will set 
     * the environment variable PW_DEPRECATED=nolog,nodelay,noexception</p>
     *  
     * @param keys the variables to set in the environment variable
     */
    public static void setEnv(EnvironmentVariableKey... keys) {
        if (keys != null && keys.length > 0) {
            StringBuilder value = new StringBuilder();
            for (EnvironmentVariableKey key : keys) {
                if (value.length() > 0) {
                    value.append(",");
                }
                value.append(key.name().toLowerCase());
            }
            setEnv(PW_DEPRECATED, value.toString());
        }
    }

    /**
     * Sets the environment variable PW_DEPRECATED to an empty string, meaning
     * all flags corresponding to the deprecation phase will be active by default.
     * @see #setEnv(boolean, boolean, boolean)
     */
    public static void clearEnv() {
        setEnv(PW_DEPRECATED, "");
    }

    /**
     * Helper hack to set environment variables from Java code
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    private static void setEnv(final String key, final String value) {
        try {
            Class<?> processEnvironmentClass = Class.forName("java.lang.ProcessEnvironment");
            Field theEnvironmentField = processEnvironmentClass.getDeclaredField("theEnvironment");
            theEnvironmentField.setAccessible(true);
            Map<String, String> env = (Map<String, String>) theEnvironmentField.get(null);
            env.put(key, value);
            Field theCaseInsensitiveEnvironmentField = processEnvironmentClass
                    .getDeclaredField("theCaseInsensitiveEnvironment");
            theCaseInsensitiveEnvironmentField.setAccessible(true);
            Map<String, String> cienv = (Map<String, String>) theCaseInsensitiveEnvironmentField.get(null);
            cienv.put(key, value);
        } catch (NoSuchFieldException e) {
            try {
                Class[] classes = Collections.class.getDeclaredClasses();
                Map<String, String> env = System.getenv();
                for (Class cl : classes) {
                    if ("java.util.Collections$UnmodifiableMap".equals(cl.getName())) {
                        Field field = cl.getDeclaredField("m");
                        field.setAccessible(true);
                        Object obj = field.get(env);
                        Map<String, String> map = (Map<String, String>) obj;
                        map.clear();
                        map.put(key, value);
                    }
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        } catch (Exception e1) {
            e1.printStackTrace();
        }
    }

}