core/src/main/java/org/jclouds/predicates/Validator.java

/**
*
* Copyright (C) 2010 Cloud Conscious, LLC. <info@cloudconscious.com>
*
* ====================================================================
* 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.jclouds.predicates;

import com.google.common.base.Predicate;

import javax.annotation.Nullable;

/**
 * Abstract class that creates a bridge between {@link com.google.common.base.Predicate}
 * and {@link org.jclouds.rest.annotations.ParamValidators}s.
 *
 * @param <T> Type of object to be validated. For generic
 * validation (where object's class is determined in {@link #validate(Object)},
 * use {@link Object}.
 *
 * @see com.google.common.base.Predicate
 *
 * @author Oleksiy Yarmula
 */
public abstract class Validator<T> implements Predicate<T> {

    @Override
    public boolean apply(@Nullable T t) {
        validate(t);
        return true; // by contract, if no exception thrown
    }

    /**
     * Validates the parameter
     * @param t parameter to be validated
     * @throws IllegalArgumentException if validation failed
     */
    public abstract void validate(@Nullable T t) throws IllegalArgumentException;
}