com.brienwheeler.lib.spring.beans.SmartXmlBeanDefinitionReader.java Source code

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Here is the source code for com.brienwheeler.lib.spring.beans.SmartXmlBeanDefinitionReader.java

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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2013 Brien L. Wheeler (brienwheeler@yahoo.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.brienwheeler.lib.spring.beans;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Set;
import java.util.concurrent.ConcurrentSkipListSet;

import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.core.io.support.EncodedResource;

/**
 * A subclass of XmlBeanDefinitionReader that does not re-read the same XML file twice.
 * Useful for preventing bean redefinition (and potential replication of anonymous beans)
 * when importing a complex tree of bean definition imports that might have duplicate
 * subtrees.  Note this does not subvert the standard cyclic import detection. 
 *  
 * @author bwheeler
 */
public class SmartXmlBeanDefinitionReader extends XmlBeanDefinitionReader {

    protected final Set<String> loadedPaths = new ConcurrentSkipListSet<String>();

    public SmartXmlBeanDefinitionReader(BeanDefinitionRegistry registry) {
        super(registry);
    }

    @Override
    public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {
        String canonicalPath = null;
        try {
            canonicalPath = encodedResource.getResource().getURL().getPath();
        } catch (IOException e) {
            // on FileNotFoundException, fall through to normal behavior -- this will probably result in a
            // FNFE from somewhere else that will make more sense.
            if (!(e instanceof FileNotFoundException))
                throw new BeanDefinitionStoreException("Error resolving canonical path for context resource", e);
        }

        if (canonicalPath != null && loadedPaths.contains(canonicalPath)) {
            if (logger.isDebugEnabled())
                logger.debug("skipping already loaded path " + canonicalPath);
            return 0;
        } else {
            int count = super.loadBeanDefinitions(encodedResource);
            if (canonicalPath != null)
                loadedPaths.add(canonicalPath);
            return count;
        }

    }
}