org.zalando.crypto.Decrypters.java Source code

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Here is the source code for org.zalando.crypto.Decrypters.java

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/**
 * Copyright (C) 2015 Zalando SE (http://tech.zalando.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.zalando.crypto;

import java.util.List;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Strings;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

/**
 * 
 * @author jbellmann
 *
 */
public final class Decrypters {

    public static List<Decrypter> prefixedDecrypters(List<Decrypter> toFilter) {
        return Lists.newArrayList(Iterables.filter(toFilter, new PrefixedDecrypterPredicate()));
    }

    public static List<Decrypter> nonPrefixedDecrypters(List<Decrypter> toFilter) {
        return Lists.newArrayList(Iterables.filter(toFilter, new PrefixedDecrypterPredicate()));
    }

    public static List<Decrypter> findByPrefix(List<Decrypter> decrypters, String prefix) {
        Preconditions.checkNotNull(decrypters, "'Decrypter's-list should not be null");
        Preconditions.checkArgument(!Strings.isNullOrEmpty(prefix), "'prefix' should never be null or empty.");
        return Lists.newArrayList(Iterables.filter(decrypters,
                Predicates.and(new PrefixedDecrypterPredicate(), new PrefixPredicate(prefix))));
    }

    static class PrefixPredicate implements Predicate<Decrypter> {

        private final String prefix;

        public PrefixPredicate(String prefix) {
            this.prefix = prefix;
        }

        @Override
        public boolean apply(Decrypter input) {
            return prefix.equals(((Prefixed) input).getPrefix());
        }

    }

    static class PrefixedDecrypterPredicate implements Predicate<Decrypter> {

        public boolean apply(Decrypter input) {
            return (input instanceof Prefixed);
        }

    }

    static class NonPrefixedDecrypterPredicate implements Predicate<Decrypter> {

        public boolean apply(Decrypter input) {
            return !(input instanceof Prefixed);
        }

    }

}