| /** |
| * 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.component.dozer; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.apache.camel.Exchange; |
| import org.apache.camel.Expression; |
| import org.apache.camel.spi.Language; |
| import org.apache.camel.util.IOHelper; |
| import org.apache.camel.util.ResourceHelper; |
| |
| /** |
| * Provides support for mapping a Camel expression to a target field in a |
| * mapping. Expressions have the following format: |
| * <br><br> |
| * [language]:[expression] |
| * <br><br> |
| */ |
| public class ExpressionMapper extends BaseConverter { |
| |
| private ThreadLocal<Exchange> currentExchange = new ThreadLocal<Exchange>(); |
| |
| @Override |
| public Object convert(Object existingDestinationFieldValue, |
| Object sourceFieldValue, |
| Class<?> destinationClass, |
| Class<?> sourceClass) { |
| try { |
| if (currentExchange.get() == null) { |
| throw new IllegalStateException( |
| "Current exchange has not been set for ExpressionMapper"); |
| } |
| |
| Expression exp; |
| |
| // Resolve the language being used for this expression and evaluate |
| Exchange exchange = currentExchange.get(); |
| Language expLang = exchange.getContext().resolveLanguage(getLanguagePart()); |
| String scheme = getSchemePart(); |
| if (scheme != null && (scheme.equalsIgnoreCase("classpath") || scheme.equalsIgnoreCase("file") || scheme.equalsIgnoreCase("http"))) { |
| String path = getPathPart(); |
| try { |
| exp = expLang.createExpression(resolveScript(scheme + ":" + path)); |
| } catch (IOException e) { |
| throw new IllegalStateException( |
| "Expression script specified but not found", e); |
| } |
| } else { |
| exp = expLang.createExpression(getExpressionPart()); |
| } |
| return exp.evaluate(exchange, destinationClass); |
| } finally { |
| done(); |
| } |
| } |
| |
| /** |
| * Resolves the script. |
| * |
| * @param script script or uri for a script to load |
| * @return the script |
| * @throws IOException is thrown if error loading the script |
| */ |
| protected String resolveScript(String script) throws IOException { |
| String answer; |
| if (ResourceHelper.hasScheme(script)) { |
| InputStream is = loadResource(script); |
| answer = currentExchange.get().getContext().getTypeConverter().convertTo(String.class, is); |
| IOHelper.close(is); |
| } else { |
| answer = script; |
| } |
| |
| return answer; |
| } |
| |
| /** |
| * Loads the given resource. |
| * |
| * @param uri uri of the resource. |
| * @return the loaded resource |
| * @throws IOException is thrown if resource is not found or cannot be loaded |
| */ |
| protected InputStream loadResource(String uri) throws IOException { |
| return ResourceHelper.resolveMandatoryResourceAsInputStream(currentExchange.get().getContext(), uri); |
| } |
| |
| /** |
| * Used as the source field for Dozer mappings. |
| */ |
| public String getExpression() { |
| return getParameter(); |
| } |
| |
| /** |
| * The actual expression, without the language prefix. |
| */ |
| public String getExpressionPart() { |
| return getParameter().substring(getParameter().indexOf(":") + 1); |
| } |
| |
| /** |
| * The expression language used for this mapping. |
| */ |
| public String getLanguagePart() { |
| return getParameter().substring(0, getParameter().indexOf(":")); |
| } |
| |
| /** |
| * Sets the Camel exchange reference for this mapping. The exchange |
| * reference is stored in a thread-local which is cleaned up after the |
| * mapping has been performed via the done() method. |
| * @param exchange |
| */ |
| public void setCurrentExchange(Exchange exchange) { |
| currentExchange.set(exchange); |
| } |
| |
| /** |
| * The scheme used for this mapping's resource file (classpath, file, http). |
| */ |
| public String getSchemePart() { |
| return getParameterPart(":", 1); |
| } |
| |
| /** |
| * The path used for this mapping's resource file. |
| */ |
| public String getPathPart() { |
| return getParameterPart(":", 2); |
| } |
| |
| /* |
| * Parse the URI to get at one of the parameters. |
| * @param separator |
| * @param idx |
| * @return |
| */ |
| private String getParameterPart(String separator, int idx) { |
| String part = null; |
| String[] parts = getParameter().split(separator); |
| if (parts.length > idx) { |
| part = parts[idx]; |
| } |
| return part; |
| } |
| |
| } |