biz.c24.io.spring.integration.router.C24XPathRouter.java Source code

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Here is the source code for biz.c24.io.spring.integration.router.C24XPathRouter.java

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/*
 * Copyright 2011 the original author or authors.
 *
 * 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 biz.c24.io.spring.integration.router;

import java.util.Collections;
import java.util.List;

import org.springframework.messaging.Message;
import org.springframework.messaging.MessagingException;
import org.springframework.integration.router.AbstractMappingMessageRouter;
import org.springframework.util.Assert;

import biz.c24.io.api.data.ComplexDataObject;
import biz.c24.io.api.data.IOXPath;
import biz.c24.io.api.data.IOXPathException;
import biz.c24.io.api.data.IOXPathFactory;
import biz.c24.io.api.data.XPathStatement;

/**
 * Message Router that uses {@link XPathStatement} evaluation to determine
 * channel names.
 * 
 * TODO Evaluate as list of strings, not just a single string.
 * 
 * @author askogman
 * 
 */
public class C24XPathRouter extends AbstractMappingMessageRouter {

    private final XPathStatement statement;

    /**
     * Create a router that uses an XPath expression.
     * 
     * @param expression
     *            the XPath expression as a String
     */
    public C24XPathRouter(String expression) {
        Assert.hasText(expression, "expression must not be empty");
        this.statement = new XPathStatement(expression);
    }

    /**
     * Create a router that uses the provided XPath statement.
     * 
     * @param statement
     *            the XPath statement
     */
    public C24XPathRouter(XPathStatement statement) {
        Assert.notNull(statement, "statement must not be null");
        this.statement = statement;
    }

    @Override
    public String getComponentType() {
        return "int-c24:xpath-router";
    }

    protected IOXPath createXPath() {
        try {
            return IOXPathFactory.getInstance(statement);
        } catch (IOXPathException e) {
            throw new MessagingException(
                    "Exception when trying to instantiate the Xpath statement [" + statement + "].", e);
        }
    }

    @Override
    protected List<Object> getChannelKeys(Message<?> message) {

        ComplexDataObject cdo;
        try {
            cdo = (ComplexDataObject) message.getPayload();
        } catch (ClassCastException e) {

            Object payload = message.getPayload();

            throw new MessagingException("Cannot route based on payloads of type [" + payload == null ? "<null>"
                    : payload.getClass().getName() + "]. Only ComplexDataObject is supported.", e);
        }

        IOXPath xPath = createXPath();

        String channel;
        try {
            channel = xPath.getString(cdo);
        } catch (IOXPathException e) {
            throw new MessagingException("Exception when trying to evaluate the Xpath statement [" + statement
                    + "] on the object [" + cdo + "] to a String.", e);
        }

        return Collections.singletonList((Object) channel);

    }
}