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    /*******************************************************************************
 * Copyright (c) 2005, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM - Initial API and implementation
 *******************************************************************************/
package com.sap.it.commons.nls;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Common superclass for all message bundle classes. Provides convenience
 * methods for manipulating messages.
 * 
    
 * The #bind methods perform string substitution and should be
 * considered a convenience and not a full substitute replacement for
 * MessageFormat#format method calls.
 * 
    
 * 
    
 * Text appearing within curly braces in the given message, will be interpreted
 * as a numeric index to the corresponding substitution object in the given
 * array. Calling the #bind methods with text that does not map to
 * an integer will result in an {@link IllegalArgumentException}.
 * 
    
 * 
    
 * Text appearing within single quotes is treated as a literal. A single quote
 * is escaped by a preceeding single quote.
 * 
    
 * 
    
 * Clients who wish to use the full substitution power of the
 * MessageFormat class should call that class directly and not use
 * these #bind methods.
 * 
    
 * 
    
 * Clients may subclass this type.
 * 
    
 * 
 * @since 3.1
 */
public abstract class NLS {

    private static final Object[] EMPTY_ARGS = new Object[0];
    private static final String EXTENSION = ".properties"; //$NON-NLS-1$
    private static String[] nlSuffixes;
    private static final Logger frameworkLog = Logger.getLogger(NLS.class.getName());

    static final int SEVERITY_ERROR = 0x04;
    static final int SEVERITY_WARNING = 0x02;
    /*
     * This object is assigned to the value of a field map to indicate that a
     * translated message has already been assigned to that field.
     */
    static final Object ASSIGNED = new Object();

    /**
     * Creates a new NLS instance.
     */
    protected NLS() {
        super();
    }

    /**
     * Bind the given message's substitution locations with the given string
     * value.
     * 
     * @param message
     *            the message to be manipulated
     * @param binding
     *            the object to be inserted into the message
     * @return the manipulated String
     * @throws IllegalArgumentException
     *             if the text appearing within curly braces in the given
     *             message does not map to an integer
     */
    public static String bind(String message, Object binding) {
        return internalBind(message, null, String.valueOf(binding), null);
    }

    /**
     * Bind the given message's substitution locations with the given string
     * values.
     * 
     * @param message
     *            the message to be manipulated
     * @param binding1
     *            An object to be inserted into the message
     * @param binding2
     *            A second object to be inserted into the message
     * @return the manipulated String
     * @throws IllegalArgumentException
     *             if the text appearing within curly braces in the given
     *             message does not map to an integer
     */
    public static String bind(String message, Object binding1, Object binding2) {
        return internalBind(message, null, String.valueOf(binding1), String.valueOf(binding2));
    }

    /**
     * Bind the given message's substitution locations with the given string
     * values.
     * 
     * @param message
     *            the message to be manipulated
     * @param bindings
     *            An array of objects to be inserted into the message
     * @return the manipulated String
     * @throws IllegalArgumentException
     *             if the text appearing within curly braces in the given
     *             message does not map to an integer
     */
    public static String bind(String message, Object[] bindings) {
        return internalBind(message, bindings, null, null);
    }

    /**
     * Initialize the given class with the values from the message properties
     * specified by the base name. The base name specifies a fully qualified
     * base name to a message properties file, including the package where the
     * message properties file is located. The class loader of the specified
     * class will be used to load the message properties resources.
     * 
    
     * For example, if the locale is set to en_US and
     * org.eclipse.example.nls.messages is used as the base name
     * then the following resources will be searched using the class loader of
     * the specified class:
     * 
     * 
         *   org/eclipse/example/nls/messages_en_US.properties
     *   org/eclipse/example/nls/messages_en.properties
     *   org/eclipse/example/nls/messages.properties
     * 
    
     * 
     * 
    
     * 
     * @param baseName
     *            the base name of a fully qualified message properties file.
     * @param clazz
     *            the class where the constants will exist
     */
    public static void initializeMessages(final String baseName, final Class clazz) {
        if (System.getSecurityManager() == null) {
            load(baseName, clazz);
            return;
        }
        AccessController.doPrivileged(new PrivilegedAction() {
            @Override
            public Object run() {
                load(baseName, clazz);
                return null;
            }
        });
    }

    /*
     * Perform the string substitution on the given message with the specified
     * args. See the class comment for exact details.
     */
    private static String internalBind(String message, Object[] args, String argZero, String argOne) {
        if (message == null)
            return "No message available."; //$NON-NLS-1$
        if (args == null || args.length == 0)
            args = EMPTY_ARGS;

        int length = message.length();
        //estimate correct size of string buffer to avoid growth
        int bufLen = length + (args.length * 5);
        if (argZero != null)
            bufLen += argZero.length() - 3;
        if (argOne != null)
            bufLen += argOne.length() - 3;
        StringBuffer buffer = new StringBuffer(bufLen < 0 ? 0 : bufLen);
        for (int i = 0; i < length; i++) {
            char c = message.charAt(i);
            switch (c) {
            case '{':
                int index = message.indexOf('}', i);
                // if we don't have a matching closing brace then...
                if (index == -1) {
                    buffer.append(c);
                    break;
                }
                i++;
                if (i >= length) {
                    buffer.append(c);
                    break;
                }
                // look for a substitution
                int number = -1;
                try {
                    number = Integer.parseInt(message.substring(i, index));
                } catch (NumberFormatException e) {
                    throw (IllegalArgumentException) new IllegalArgumentException().initCause(e);
                }
                if (number == 0 && argZero != null)
                    buffer.append(argZero);
                else if (number == 1 && argOne != null)
                    buffer.append(argOne);
                else {
                    if (number >= args.length || number < 0) {
                        buffer.append(""); //$NON-NLS-1$
                        i = index;
                        break;
                    }
                    buffer.append(args[number]);
                }
                i = index;
                break;
            case '\'':
                // if a single quote is the last char on the line then skip it
                int nextIndex = i + 1;
                if (nextIndex >= length) {
                    buffer.append(c);
                    break;
                }
                char next = message.charAt(nextIndex);
                // if the next char is another single quote then write out one
                if (next == '\'') {
                    i++;
                    buffer.append(c);
                    break;
                }
                // otherwise we want to read until we get to the next single quote
                index = message.indexOf('\'', nextIndex);
                // if there are no more in the string, then skip it
                if (index == -1) {
                    buffer.append(c);
                    break;
                }
                // otherwise write out the chars inside the quotes
                buffer.append(message.substring(nextIndex, index));
                i = index;
                break;
            default:
                buffer.append(c);
            }
        }
        return buffer.toString();
    }

    /*
     * Build an array of property files to search. The returned array contains
     * the property fields in order from most specific to most generic. So, in
     * the FR_fr locale, it will return file_fr_FR.properties, then
     * file_fr.properties, and finally file.properties.
     */
    private static String[] buildVariants(String root) {
        if (nlSuffixes == null) {
            //build list of suffixes for loading resource bundles
            String nl = Locale.getDefault().toString();
            List result = new ArrayList(4);
            int lastSeparator;
            while (true) {
                result.add('_' + nl + EXTENSION);
                lastSeparator = nl.lastIndexOf('_');
                if (lastSeparator == -1)
                    break;
                nl = nl.substring(0, lastSeparator);
            }
            //add the empty suffix last (most general)
            result.add(EXTENSION);
            nlSuffixes = result.toArray(new String[result.size()]);
        }
        root = root.replace('.', '/');
        String[] variants = new String[nlSuffixes.length];
        for (int i = 0; i < variants.length; i++)
            variants[i] = root + nlSuffixes[i];
        return variants;
    }

    private static void computeMissingMessages(String bundleName, Class clazz, Map fieldMap, Field[] fieldArray,
            boolean isAccessible) {
        // iterate over the fields in the class to make sure that there aren't any empty ones
        final int MOD_EXPECTED = Modifier.PUBLIC | Modifier.STATIC;
        final int MOD_MASK = MOD_EXPECTED | Modifier.FINAL;
        final int numFields = fieldArray.length;
        for (int i = 0; i < numFields; i++) {
            Field field = fieldArray[i];
            if ((field.getModifiers() & MOD_MASK) != MOD_EXPECTED)
                continue;
            //if the field has a a value assigned, there is nothing to do
            if (fieldMap.get(field.getName()) == ASSIGNED)
                continue;
            try {
                // Set a value for this empty field. We should never get an exception here because
                // we know we have a public static non-final field. If we do get an exception, silently
                // log it and continue. This means that the field will (most likely) be un-initialized and
                // will fail later in the code and if so then we will see both the NPE and this error.
                String value = "NLS missing message: " + field.getName() + " in: " + bundleName; //$NON-NLS-1$ //$NON-NLS-2$
                log(SEVERITY_WARNING, value, null);
                if (!isAccessible)
                    field.setAccessible(true);
                field.set(null, value);
            } catch (Exception e) {
                log(SEVERITY_ERROR, "Error setting the missing message value for: " + field.getName(), e); //$NON-NLS-1$
            }
        }
    }

    /*
     * Load the given resource bundle using the specified class loader.
     */
    static void load(final String bundleName, Class clazz) {
        final Field[] fieldArray = clazz.getDeclaredFields();
        ClassLoader loader = clazz.getClassLoader();

        boolean isAccessible = (clazz.getModifiers() & Modifier.PUBLIC) != 0;

        //build a map of field names to Field objects
        final int len = fieldArray.length;
        Map fields = new HashMap(len * 2);
        for (int i = 0; i < len; i++)
            fields.put(fieldArray[i].getName(), fieldArray[i]);

        // search the variants from most specific to most general, since
        // the MessagesProperties.put method will mark assigned fields
        // to prevent them from being assigned twice
        final String[] variants = buildVariants(bundleName);
        for (int i = 0; i < variants.length; i++) {
            // loader==null if we're launched off the Java boot classpath
            final InputStream input = loader == null ? ClassLoader.getSystemResourceAsStream(variants[i]) : loader
                    .getResourceAsStream(variants[i]);
            if (input == null)
                continue;
            try {
                final MessagesProperties properties = new MessagesProperties(fields, bundleName, isAccessible);
                properties.load(input);
            } catch (IOException e) {
                log(SEVERITY_ERROR, "Error loading " + variants[i], e); //$NON-NLS-1$
            } finally {
                if (input != null)
                    try {
                        input.close();
                    } catch (IOException e) {
                        // ignore
                    }
            }
        }
        computeMissingMessages(bundleName, clazz, fields, fieldArray, isAccessible);
    }

    /*
     * The method adds a log entry based on the error message and exception. The
     * output is written to the System.err.
     * 
     * This method is only expected to be called if there is a problem in the
     * NLS mechanism. As a result, translation facility is not available here
     * and messages coming out of this log are generally not translated.
     * 
     * @param severity - severity of the message (SEVERITY_ERROR or
     * SEVERITY_WARNING)
     * 
     * @param message - message to log
     * 
     * @param e - exception to log
     */
    static void log(int severity, String message, Exception e) {
        if (frameworkLog != null) {
            switch (severity) {
            case SEVERITY_ERROR:
                frameworkLog.log(Level.SEVERE, message, e);
                break;
            case SEVERITY_WARNING:
                frameworkLog.log(Level.WARNING, message, e);
                break;
            default:
                frameworkLog.log(Level.INFO, message, e);
                break;
            }
            return;
        }
    }

    /*
     * Class which sub-classes java.util.Properties and uses the #put method to
     * set field values rather than storing the values in the table.
     */
    private static class MessagesProperties extends Properties {

        private static final int MOD_EXPECTED = Modifier.PUBLIC | Modifier.STATIC;
        private static final int MOD_MASK = MOD_EXPECTED | Modifier.FINAL;
        private static final long serialVersionUID = 1L;

        private final String bundleName;
        private final Map fields;
        private final boolean isAccessible;

        public MessagesProperties(Map fieldMap, String bundleName, boolean isAccessible) {
            super();
            this.fields = fieldMap;
            this.bundleName = bundleName;
            this.isAccessible = isAccessible;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.util.Hashtable#put(java.lang.Object, java.lang.Object)
         */
        @Override
        public synchronized Object put(Object key, Object value) {
            Object fieldObject = fields.put(key, ASSIGNED);
            // if already assigned, there is nothing to do
            if (fieldObject == ASSIGNED)
                return null;
            if (fieldObject == null) {
                final String msg = "NLS unused message: " + key + " in: " + bundleName;//$NON-NLS-1$ //$NON-NLS-2$
                log(SEVERITY_WARNING, msg, null);
                return null;
            }
            final Field field = (Field) fieldObject;
            //can only set value of public static non-final fields
            if ((field.getModifiers() & MOD_MASK) != MOD_EXPECTED)
                return null;
            try {
                // Check to see if we are allowed to modify the field. If we aren't (for instance 
                // if the class is not public) then change the accessible attribute of the field
                // before trying to set the value.
                if (!isAccessible)
                    field.setAccessible(true);
                // Set the value into the field. We should never get an exception here because
                // we know we have a public static non-final field. If we do get an exception, silently
                // log it and continue. This means that the field will (most likely) be un-initialized and
                // will fail later in the code and if so then we will see both the NPE and this error.

                // Extra care is taken to be sure we create a String with its own backing char[] (bug 287183)
                // This is to ensure we do not keep the key chars in memory.
                field.set(null, new String(((String) value).toCharArray()));
            } catch (Exception e) {
                log(SEVERITY_ERROR, "Exception setting field value.", e); //$NON-NLS-1$
            }
            return null;
        }
    }
}    
    
    
    

    




    
    
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