/*
* Copyright © 2016 Cask Data, Inc.
* Portions copyright (C) 2011 The Guava Authors
* Derived from the Google Guava Project
*
* 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 co.cask.cdap.internal.guava.reflect;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import javax.annotation.Nullable;
/**
* Captures a free type variable that can be used in {@link TypeToken#where}.
* For example:
*
* <pre> {@code
* static <T> TypeToken<List<T>> listOf(Class<T> elementType) {
* return new TypeToken<List<T>>() {}
* .where(new TypeParameter<T>() {}, elementType);
* }}</pre>
*
* @param <T> Type being captured
*
*/
public abstract class TypeParameter<T> extends TypeCapture<T> {
final TypeVariable<?> typeVariable;
protected TypeParameter() {
Type type = capture();
Preconditions.checkArgument(type instanceof TypeVariable, "%s should be a type variable.", type);
this.typeVariable = (TypeVariable<?>) type;
}
@Override public final int hashCode() {
return typeVariable.hashCode();
}
@Override public final boolean equals(@Nullable Object o) {
if (o instanceof TypeParameter) {
TypeParameter<?> that = (TypeParameter<?>) o;
return typeVariable.equals(that.typeVariable);
}
return false;
}
@Override public String toString() {
return typeVariable.toString();
}
}