// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 *******************************************************************************
 * Copyright (C) 2003-2015, International Business Machines Corporation and
 * others. All Rights Reserved.
 *******************************************************************************
 */
package com.ibm.icu.text;

import java.text.Format;

import com.ibm.icu.util.ULocale;

/**
 * An abstract class that extends {@link java.text.Format} to provide
 * additional ICU protocol, specifically, the <tt>getLocale()</tt>
 * API.  All ICU format classes are subclasses of this class.
 *
 * @see com.ibm.icu.util.ULocale
 * @author weiv
 * @author Alan Liu
 * @stable ICU 2.8
 */
public abstract class UFormat extends Format {
    // jdk1.4.2 serialver
    private static final long serialVersionUID = -4964390515840164416L;

    /**
     * A field that represents a span of text that may be composed with other fields.
     * SpanField classes usually have an associated value.
     *
     * @stable ICU 64
     */
    public static abstract class SpanField extends Format.Field {
        private static final long serialVersionUID = -4732719509273350606L;

        /**
         * Construct a new instance.
         *
         * @stable ICU 64
         */
        protected SpanField(String name) {
            super(name);
        }
    }

    /**
     * Default constructor.
     *
     * @stable ICU 2.8
     */
    public UFormat() {}

    // -------- BEGIN ULocale boilerplate --------

    /**
     * Return the locale that was used to create this object, or null.
     * This may may differ from the locale requested at the time of
     * this object's creation.  For example, if an object is created
     * for locale <tt>en_US_CALIFORNIA</tt>, the actual data may be
     * drawn from <tt>en</tt> (the <i>actual</i> locale), and
     * <tt>en_US</tt> may be the most specific locale that exists (the
     * <i>valid</i> locale).
     *
     * <p>Note: This method will be implemented in ICU 3.0; ICU 2.8
     * contains a partial preview implementation.  The <i>actual</i>
     * locale is returned correctly, but the <i>valid</i> locale is
     * not, in most cases.
     * @param type type of information requested, either {@link
     * com.ibm.icu.util.ULocale#VALID_LOCALE} or {@link
     * com.ibm.icu.util.ULocale#ACTUAL_LOCALE}.
     * @return the information specified by <i>type</i>, or null if
     * this object was not constructed from locale data.
     * @see com.ibm.icu.util.ULocale
     * @see com.ibm.icu.util.ULocale#VALID_LOCALE
     * @see com.ibm.icu.util.ULocale#ACTUAL_LOCALE
     * @draft ICU 2.8 (retain)
     * @provisional This API might change or be removed in a future release.
     */
    public final ULocale getLocale(ULocale.Type type) {
        return type == ULocale.ACTUAL_LOCALE ?
            this.actualLocale : this.validLocale;
    }

    /**
     * Set information about the locales that were used to create this
     * object.  If the object was not constructed from locale data,
     * both arguments should be set to null.  Otherwise, neither
     * should be null.  The actual locale must be at the same level or
     * less specific than the valid locale.  This method is intended
     * for use by factories or other entities that create objects of
     * this class.
     * @param valid the most specific locale containing any resource
     * data, or null
     * @param actual the locale containing data used to construct this
     * object, or null
     * @see com.ibm.icu.util.ULocale
     * @see com.ibm.icu.util.ULocale#VALID_LOCALE
     * @see com.ibm.icu.util.ULocale#ACTUAL_LOCALE
     */
    final void setLocale(ULocale valid, ULocale actual) {
        // Change the following to an assertion later
        if ((valid == null) != (actual == null)) {
            ///CLOVER:OFF
            throw new IllegalArgumentException();
            ///CLOVER:ON
        }
        // Another check we could do is that the actual locale is at
        // the same level or less specific than the valid locale.
        this.validLocale = valid;
        this.actualLocale = actual;
    }

    /**
     * The most specific locale containing any resource data, or null.
     * @see com.ibm.icu.util.ULocale
     */
    private ULocale validLocale;

    /**
     * The locale containing data used to construct this object, or
     * null.
     * @see com.ibm.icu.util.ULocale
     */
    private ULocale actualLocale;

    // -------- END ULocale boilerplate --------
}