com.google.common.css.MultipleMappingSubstitutionMap Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of closure-stylesheets Show documentation

Closure Stylesheets is an extension to CSS that adds variables, functions, conditionals, and mixins to standard CSS. The tool also supports minification, linting, RTL flipping, and CSS class renaming.

There is a newer version: 1.8.0

Show newest version

/*
 * Copyright 2011 Google Inc.
 *
 * 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 com.google.common.css;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;

import java.util.Map;

/**
 * {@link MultipleMappingSubstitutionMap} is a special type of
 * {@link SubstitutionMap} that can create multiple mappings for a single
 * lookup. This is particularly important with respect to CSS renaming.
 * 
 * For example, a {@link SplittingSubstitutionMap} may rename "goog-component"
 * as "a-b", in which case it has created two renaming mappings: "a" -> "goog"
 * and "b" -> "component", both of which are necessary to produce the full
 * renaming map.
 * 

 * Note that in the case of {@link SplittingSubstitutionMap}, the map that is
 * returned by {@link #getValueWithMappings(String)} does not contain
 * "goog-component" as a key because the entries "goog" and "component" are
 * sufficient to construct the renamed version of "goog-component". Therefore,
 * the key passed into {@link #getValueWithMappings(String)} is not guaranteed
 * to appear in the output.
 *
 * @author [email protected] (Michael Bolin)
 */
public interface MultipleMappingSubstitutionMap extends SubstitutionMap {

    /**
     * Contains both the value and mappings returned by
     * {@link MultipleMappingSubstitutionMap#getValueWithMappings(String)}.
     */
    class ValueWithMappings {
        public final String value;
        public final Map mappings;

        private ValueWithMappings(String value, Map mappings) {
            Preconditions.checkNotNull(value);
            Preconditions.checkNotNull(mappings);
            this.value = value;
            this.mappings = ImmutableMap.copyOf(mappings);
        }

        public static ValueWithMappings createWithValueAndMappings(String value,
                                                                   Map mappings) {
            return new ValueWithMappings(value, mappings);
        }

        public static ValueWithMappings createForSingleMapping(String key, String value) {
            return new ValueWithMappings(value, ImmutableMap.of(key, value));
        }
    }

    /**
     * Like an ordinary {@link SubstitutionMap}, this returns a value to
     * substitute for the specified {@code key}. This value is available as
     * {@link ValueWithMappings#value}.
     * 
     * Additionally, it also returns any renaming mappings that should be
     * associated with this substitution. These mappings are available as
     * {@link ValueWithMappings#mappings}.
     */
    ValueWithMappings getValueWithMappings(String key);
}