/**
* 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.simple;
import java.util.ArrayList;
import java.util.List;
import org.apache.camel.Exchange;
import org.apache.camel.Expression;
import org.apache.camel.Predicate;
import org.apache.camel.builder.ExpressionBuilder;
import org.apache.camel.builder.PredicateBuilder;
import org.apache.camel.spi.Language;
/**
* Abstract base class for Simple languages.
*/
public abstract class AbstractSimpleLanguage implements Language {
public Predicate<Exchange> createPredicate(String expression) {
return PredicateBuilder.toPredicate(createExpression(expression));
}
public Expression<Exchange> createExpression(String expression) {
if (expression.indexOf("${") >= 0) {
return createComplexExpression(expression);
}
return createSimpleExpression(expression);
}
protected Expression<Exchange> createComplexExpression(String expression) {
List<Expression> results = new ArrayList<Expression>();
int pivot = 0;
int size = expression.length();
while (pivot < size) {
int idx = expression.indexOf("${", pivot);
if (idx < 0) {
results.add(createConstantExpression(expression, pivot, size));
break;
} else {
if (pivot < idx) {
results.add(createConstantExpression(expression, pivot, idx));
}
pivot = idx + 2;
int endIdx = expression.indexOf("}", pivot);
if (endIdx < 0) {
throw new IllegalArgumentException("Expecting } but found end of string for simple expression: " + expression);
}
String simpleText = expression.substring(pivot, endIdx);
Expression simpleExpression = createSimpleExpression(simpleText);
results.add(simpleExpression);
pivot = endIdx + 1;
}
}
return ExpressionBuilder.concatExpression(results, expression);
}
protected Expression createConstantExpression(String expression, int start, int end) {
return ExpressionBuilder.constantExpression(expression.substring(start, end));
}
/**
* Creates the simple expression based on the extracted content from the ${ } place holders
*
* @param expression the content between ${ and }
* @return the expression
*/
protected abstract <E extends Exchange> Expression<Exchange> createSimpleExpression(String expression);
protected String ifStartsWithReturnRemainder(String prefix, String text) {
if (text.startsWith(prefix)) {
String remainder = text.substring(prefix.length());
if (remainder.length() > 0) {
return remainder;
}
}
return null;
}
}