com.spoledge.util.xslt.ResourceURIResolver.java Source code

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Here is the source code for com.spoledge.util.xslt.ResourceURIResolver.java

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/*
 * Copyright 2010 Spolecne s.r.o. (www.spoledge.com)
 *
 * 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 com.spoledge.util.xslt;

import java.io.InputStream;

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.URIResolver;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This is a simple URI resolver which resolves the URIs
 * against the resources included in the jar file.
 *
 * If the TemplatesCache is set, then it first looks into 
 * it and if not found then it creates it and put it into the cache.
 * Otherwise it creates a new Source.
 */
public class ResourceURIResolver implements URIResolver {

    private String root;
    private TemplatesCache templatesCache;

    private Log log = LogFactory.getLog(getClass());

    ////////////////////////////////////////////////////////////////////////////
    // Constructors
    ////////////////////////////////////////////////////////////////////////////

    /**
     * Creates an empty resolver with root "/".
     */
    public ResourceURIResolver() {
        this("");
    }

    /**
     * Creates an empty resolver with specified root.
     * @param root the root directory of the Jar where all the resources must reside; use slashes "/"
     */
    public ResourceURIResolver(String root) {
        this(root, null);
    }

    /**
     * Creates an empty resolver with specified root.
     * @param root the root directory of the Jar where all the resources must reside; use slashes "/"
     */
    public ResourceURIResolver(String root, TemplatesCache cache) {
        if (root == null)
            root = "";
        else if (root.endsWith("/"))
            root = root.length() == 1 ? "" : root.substring(0, root.length() - 1);

        this.root = root;
        this.templatesCache = cache;
    }

    ////////////////////////////////////////////////////////////////////////////
    // URIResolver
    ////////////////////////////////////////////////////////////////////////////

    /**
     * Called by the processor when it encounters an xsl:include, xsl:import, or document() function.
     */
    public Source resolve(String href, String base) throws TransformerException {
        if (log.isDebugEnabled()) {
            log.debug("resolve(): " + base + " -> " + href);
        }

        String key = root;

        if (base != null) {
            // fix Windows paths - dir separator
            base = base.replace('\\', '/');

            if (base.startsWith("file://"))
                base = base.substring(7);
            else if (base.startsWith("file:"))
                base = base.substring(5);

            // fix Windows paths - prefix "C:"
            if (base.length() > 2 && base.charAt(2) == ':') {
                base = base.substring(3);
            } else if (base.length() > 1 && base.charAt(1) == ':') {
                base = base.substring(2);
            }

            // crop the last element
            key = base.substring(0, base.lastIndexOf('/'));
        }

        while (href.startsWith("../")) {
            int index = key.lastIndexOf('/');
            key = key.substring(0, index);
            href = href.substring(3);
        }

        if (!href.startsWith("/"))
            href = "/" + href;

        key += href;

        if (log.isDebugEnabled()) {
            log.debug("resolve(): key=" + key);
        }

        return getSource(key);
    }

    ////////////////////////////////////////////////////////////////////////////
    // Private
    ////////////////////////////////////////////////////////////////////////////

    private Source getSource(String path) {
        InputStream is = getClass().getResourceAsStream(path);

        if (is == null) {
            log.warn("getSource(): cannot find resource '" + path + "'");
        }

        return new StreamSource(is, path);
    }
}