camel-2.8.x/camel-core/src/main/java/org/apache/camel/language/header/HeaderLanguage.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.camel.language.header;

import org.apache.camel.Expression;
import org.apache.camel.IsSingleton;
import org.apache.camel.Predicate;
import org.apache.camel.builder.ExpressionBuilder;
import org.apache.camel.builder.PredicateBuilder;
import org.apache.camel.spi.Language;

/**
 * A language for header expressions.
 */
public class HeaderLanguage implements Language, IsSingleton {

    public static Expression header(String headerName) {        
        return ExpressionBuilder.headerExpression(headerName);
    }

    public Predicate createPredicate(String expression) {
        return PredicateBuilder.toPredicate(createExpression(expression));
    }

    public Expression createExpression(String expression) {
        return HeaderLanguage.header(expression);
    }

    public boolean isSingleton() {
        return true;
    }
}