PrefixingSubstitutionMap.java

/*
 * 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 java.util.Map;

/**
 * A {@link SubstitutionMap} implementation that prefixes the renamed CSS class names (provided by a
 * delegate substitution map).
 *
 */
public class PrefixingSubstitutionMap
    implements MultipleMappingSubstitutionMap, SubstitutionMap.Initializable {
  private final SubstitutionMap delegate;
  private final String prefix;

  public PrefixingSubstitutionMap(SubstitutionMap delegate, String prefix) {
    this.delegate = delegate;
    this.prefix = prefix;
  }

  @Override
  public void initializeWithMappings(Map<? extends String, ? extends String> newMappings) {
    if (!newMappings.isEmpty()) {
      // We don't need to remove prefixes from mapping values because the mappings
      // returned by getValueWithMappings are not prefixed.
      ((SubstitutionMap.Initializable) delegate).initializeWithMappings(newMappings);
    }
  }

  @Override
  public String get(String key) {
    return prefix + delegate.get(key);
  }

  @Override
  public ValueWithMappings getValueWithMappings(String key) {
    if (delegate instanceof MultipleMappingSubstitutionMap) {
      ValueWithMappings withoutPrefix =
          ((MultipleMappingSubstitutionMap) delegate).getValueWithMappings(key);
      return ValueWithMappings.createWithValueAndMappings(
          prefix + withoutPrefix.value, withoutPrefix.mappings);
    } else {
      return ValueWithMappings.createForSingleMapping(key, get(key));
    }
  }
}