MethodIntrospector.java example

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FreeBuilder-master
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/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * 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 org.inferred.freebuilder.processor;

import com.google.common.collect.ImmutableSet;

import java.util.Set;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Name;

/** Compiler-specific methods for introspecting methods during compilation. */
public abstract class MethodIntrospector {

  /**
   * Returns a set of methods which are definitely invoked on {@code this} in the given method,
   * or the empty set if method introspection is not supported on this compiler.
   */
  public abstract Set<Name> getOwnMethodInvocations(ExecutableElement method);

  /** Returns a {@link MethodIntrospector} implementation for the given environment. */
  public static MethodIntrospector instance(ProcessingEnvironment env) {
    try {
      return JavacMethodIntrospector.instance(env);
    } catch (IllegalArgumentException e) {
      return new NoMethodIntrospector();
    } catch (LinkageError e) {
      return new NoMethodIntrospector();
    }
  }

  static class NoMethodIntrospector extends MethodIntrospector {
    @Override
    public Set<Name> getOwnMethodInvocations(ExecutableElement method) {
      return ImmutableSet.of();
    }
  }
}