/**
* 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.web.util;
import org.apache.camel.builder.ExpressionClause;
import org.apache.camel.model.language.ExpressionDefinition;
import org.apache.camel.model.language.MethodCallExpression;
import org.apache.camel.model.language.XPathExpression;
public final class ExpressionRenderer {
private ExpressionRenderer() {
// Utility class, no public or protected default constructor
}
/**
* a common render method to process the expressionDefinition
*/
public static void render(StringBuilder buffer, ExpressionDefinition expression) {
if (buffer.toString().endsWith(")")) {
buffer.append(".");
}
if (expression instanceof ExpressionClause) {
renderExpressionClause(buffer, (ExpressionClause)expression);
} else if (expression.getExpressionValue() instanceof ExpressionClause) {
render(buffer, (ExpressionClause)expression.getExpressionValue());
} else {
if (expression.getExpressionValue() != null) {
renderExpression(buffer, expression.getExpressionValue().toString());
} else if (expression.getLanguage() != null) {
renderLanguageExpression(buffer, expression);
}
}
}
/**
* Render a constant: constant("")
*/
public static void renderConstant(StringBuilder buffer, ExpressionDefinition expression) {
renderConstant(buffer, expression.getExpressionValue().toString());
}
/**
* Render a constant: constant("")
*/
public static void renderConstant(StringBuilder buffer, String expression) {
if (buffer.toString().endsWith(")")) {
buffer.append(".");
}
buffer.append("constant(\"").append(expression).append("\")");
}
/**
* Render an expression clause
*/
private static void renderExpressionClause(StringBuilder buffer, ExpressionClause expression) {
if (expression.getLanguage() != null) {
// render a language expression
renderLanguageExpression(buffer, expression);
} else if (expression.getExpressionType() instanceof MethodCallExpression) {
// render a methodCall expression
String exp = expression.getExpressionType().toString();
String bean = exp.substring(exp.indexOf('{') + 1, exp.indexOf(','));
String method = exp.substring(exp.indexOf('=') + 1, exp.indexOf('}'));
buffer.append("method(\"").append(bean).append("\", \"").append(method).append("\")");
} else if (expression.getExpressionType() instanceof XPathExpression) {
XPathExpression xpath = (XPathExpression)expression.getExpressionType();
buffer.append("xpath(\"").append(xpath.getExpression()).append("\", ").append(xpath.getResultType().getSimpleName()).append(".class)");
} else {
renderExpression(buffer, expression.getExpressionValue().toString());
}
}
/**
* Render a language expression
*
* @param buffer
* @param expression
*/
public static void renderLanguageExpression(StringBuilder buffer, ExpressionDefinition expression) {
// render a language expression
buffer.append(expression.getLanguage()).append("(\"");
if (expression.getExpression() != null) {
buffer.append(expression.getExpression()).append("\")");
} else if (expression.getExpressionValue() instanceof ExpressionClause) {
buffer.append(((ExpressionClause)expression.getExpressionValue()).getExpression()).append("\")");
}
}
/**
* Render a simple expression: header(foo) -> header("foo")
* tokenize(header(foo), ,) -> header("foo").tokenize(",")
*/
public static void renderExpression(StringBuilder buffer, String expression) {
if (!expression.contains(",")) {
if (expression.contains("(")) {
// header(foo) -> header("foo")
expression = expression.replaceAll("\\(", "(\"").replaceAll("\\)", "\")");
buffer.append(expression);
} else {
// body -> body()
buffer.append(expression).append("()");
}
} else if (expression.startsWith("tokenize")) {
String words[] = expression.split("\\(");
if (words.length == 2) {
// tokenize(body, ,) -> body().tokenize(",")
String tokenize = words[1].substring(words[1].indexOf(" ") + 1, words[1].lastIndexOf(")"));
words[1] = words[1].substring(0, words[1].indexOf(","));
if (!words[1].contains("[")) {
// body
buffer.append(words[1]).append("()");
} else {
// bodyAs[clazz]
String word = words[1].substring(0, words[1].indexOf("As"));
String clazz = words[1].substring(words[1].lastIndexOf(".") + 1, words[1].length() - 1);
buffer.append(word).append("(").append(clazz).append(".class)");
}
buffer.append(".").append(words[0]).append("(\"").append(tokenize).append("\")");
} else if (words.length == 3) {
// tokenize(header(foo), ,) -> header("foo").tokenize(",")
String symbolName = words[2].substring(0, words[2].indexOf(")"));
String tokenize = words[2].substring(words[2].indexOf(" ") + 1, words[2].lastIndexOf(")"));
buffer.append(words[1]).append("(\"").append(symbolName).append("\").");
buffer.append(words[0]).append("(\"").append(tokenize).append("\")");
}
} else if (expression.startsWith("append")) {
// append(body, World!) -> body().append(" World!")
String words[] = expression.split("\\(|, |\\)");
buffer.append(words[1]).append("().").append("append(\"").append(words[2]).append("\")");
} else if (expression.startsWith("prepend")) {
// prepend(body, World!) -> body().prepend(" World!")
String words[] = expression.split("\\(|, |\\)");
buffer.append(words[1]).append("().").append("prepend(\"").append(words[2]).append("\")");
}
}
}