org.springframework.integration.xml.transformer.ResultToStringTransformer.java Source code

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Here is the source code for org.springframework.integration.xml.transformer.ResultToStringTransformer.java

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/*
 * Copyright 2002-2019 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
 *
 *      https://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.springframework.integration.xml.transformer;

import java.util.Properties;

import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;

import org.springframework.messaging.MessagingException;
import org.springframework.util.Assert;
import org.springframework.xml.transform.StringResult;
import org.springframework.xml.transform.TransformerFactoryUtils;

/**
 * Converts the passed {@link Result} to an instance of {@link String}.
 * Supports {@link StringResult} and {@link DOMResult}
 *
 * @author Jonas Partner
 * @author Mark Fisher
 * @author Artem Bilan
 */
public class ResultToStringTransformer implements ResultTransformer {

    private final TransformerFactory transformerFactory;

    private Properties outputProperties;

    public ResultToStringTransformer() {
        this.transformerFactory = TransformerFactoryUtils.newInstance();
    }

    /**
     * Construct an instance based on the provided {@link TransformerFactory}.
     * @param transformerFactory the {@link TransformerFactory} to use.
     * @since 4.3.19
     */
    public ResultToStringTransformer(TransformerFactory transformerFactory) {
        Assert.notNull(transformerFactory, "'transformerFactory' must not be null.");
        this.transformerFactory = transformerFactory;
    }

    public void setOutputProperties(Properties outputProperties) {
        this.outputProperties = outputProperties;
    }

    public Object transformResult(Result result) {
        String returnString = null;
        if (result instanceof StringResult) {
            returnString = result.toString();
        } else if (result instanceof DOMResult) {
            try {
                StringResult stringResult = new StringResult();
                getNewTransformer().transform(new DOMSource(((DOMResult) result).getNode()), stringResult);
                returnString = stringResult.toString();
            } catch (TransformerException e) {
                throw new MessagingException("failed to transform from DOMSource failed", e);
            }
        }
        if (returnString == null) {
            throw new MessagingException(
                    "failed to convert Result type [" + result.getClass().getName() + "] to string");
        }
        return returnString;
    }

    private Transformer getNewTransformer() throws TransformerConfigurationException {
        Transformer transformer;
        synchronized (this.transformerFactory) {
            transformer = this.transformerFactory.newTransformer();
        }
        if (this.outputProperties != null) {
            transformer.setOutputProperties(this.outputProperties);
        }
        return transformer;
    }

}