VariableSubstituter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.shindig.gadgets.variables;

import java.util.List;

import com.google.common.collect.ImmutableList;
import com.google.inject.Inject;
import com.google.inject.name.Named;

import org.apache.shindig.gadgets.GadgetContext;
import org.apache.shindig.gadgets.GadgetException;
import org.apache.shindig.gadgets.spec.GadgetSpec;

/**
 * Performs variable substitution on a gadget spec.
 */
public class VariableSubstituter {
  private final List<Substituter> substituters;

  @Inject
  public VariableSubstituter(@Named("shindig.substituters.gadget") List<Substituter> substituters) {
    this.substituters = ImmutableList.copyOf(substituters);
  }

  /**
   * Substitutes all hangman variables into the gadget spec.
   *
   * @return A new GadgetSpec, with all fields substituted as needed.
   */
  public GadgetSpec substitute(GadgetContext context, GadgetSpec spec) throws GadgetException {   
    Substitutions substitutions = new Substitutions();
    
    for (Substituter substituter : substituters) {
        substituter.addSubstitutions(substitutions, context, spec);
    }
    
    return spec.substitute(substitutions);
  }
}