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/*
* All content copyright Terracotta, Inc., unless otherwise indicated.
*
* 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.terracotta.context.query;
import java.lang.reflect.Method;
/**
* A matching object that can be used to filter the node-set in a context query
* chain.
*
* @param the enclosing type of the objects that match
*/
public abstract class Matcher {
private Class boundType = (Class) getSafeType(getClass());
private static > Class getSafeType(Class fromClass) {
for (Class c = fromClass; c != Object.class; c = c.getSuperclass()) {
for (Method method : c.getDeclaredMethods()) {
if (method.getName().equals("matchesSafely")
&& method.getParameterTypes().length == 1
&& !method.isSynthetic()) {
return method.getParameterTypes()[0];
}
}
}
throw new AssertionError();
}
/**
* Returns true if this object matches successfully.
*
* This method checks for a type match against the erased type of this matcher
* and then defers to the {@link #matchesSafely(Object)} of this matcher with the
* type-checked and cast object.
*
* @param object object to be checked
* @return {@code true} if the object matches
*/
public final boolean matches(Object object) {
if (boundType.isAssignableFrom(object.getClass())) {
return matchesSafely(boundType.cast(object));
} else {
return false;
}
}
/**
* Returns {@code true} if the supplied object matches against this matcher.
*
* @param object object to check for a match
* @return {@code true} on a match
*/
protected abstract boolean matchesSafely(T object);
}