001: /*
002: * Copyright (c) 2003 The Visigoth Software Society. All rights
003: * reserved.
004: *
005: * Redistribution and use in source and binary forms, with or without
006: * modification, are permitted provided that the following conditions
007: * are met:
008: *
009: * 1. Redistributions of source code must retain the above copyright
010: * notice, this list of conditions and the following disclaimer.
011: *
012: * 2. Redistributions in binary form must reproduce the above copyright
013: * notice, this list of conditions and the following disclaimer in
014: * the documentation and/or other materials provided with the
015: * distribution.
016: *
017: * 3. The end-user documentation included with the redistribution, if
018: * any, must include the following acknowledgement:
019: * "This product includes software developed by the
020: * Visigoth Software Society (http://www.visigoths.org/)."
021: * Alternately, this acknowledgement may appear in the software itself,
022: * if and wherever such third-party acknowledgements normally appear.
023: *
024: * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
025: * project contributors may be used to endorse or promote products derived
026: * from this software without prior written permission. For written
027: * permission, please contact visigoths@visigoths.org.
028: *
029: * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
030: * nor may "FreeMarker" or "Visigoth" appear in their names
031: * without prior written permission of the Visigoth Software Society.
032: *
033: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
034: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
035: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
036: * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
037: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
038: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
039: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
040: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
041: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
042: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
043: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
044: * SUCH DAMAGE.
045: * ====================================================================
046: *
047: * This software consists of voluntary contributions made by many
048: * individuals on behalf of the Visigoth Software Society. For more
049: * information on the Visigoth Software Society, please see
050: * http://www.visigoths.org/
051: */
052:
053: package freemarker.cache;
054:
055: import java.io.IOException;
056: import java.io.InputStreamReader;
057: import java.io.Reader;
058: import java.net.URL;
059:
060: /**
061: * This is an abstract template loader that can load templates whose
062: * location can be described by an URL. Subclasses only need to override
063: * the {@link #getURL(String)} method. Both {@link ClassTemplateLoader} and
064: * {@link WebappTemplateLoader} are (quite trivial) subclasses of this class.
065: * @version $Id: URLTemplateLoader.java,v 1.14 2003/01/29 08:01:17 szegedia Exp $
066: * @author Attila Szegedi
067: */
068: public abstract class URLTemplateLoader implements TemplateLoader {
069: public Object findTemplateSource(String name) throws IOException {
070: URL url = getURL(name);
071: return url == null ? null : new URLTemplateSource(url);
072: }
073:
074: /**
075: * Given a template name (plus potential locale decorations) retrieves
076: * an URL that points the template source.
077: * @param name the name of the sought template, including the locale
078: * decorations.
079: * @return an URL that points to the template source, or null if it can
080: * determine that the template source does not exist.
081: */
082: protected abstract URL getURL(String name);
083:
084: public long getLastModified(Object templateSource) {
085: return ((URLTemplateSource) templateSource).lastModified();
086: }
087:
088: public Reader getReader(Object templateSource, String encoding)
089: throws IOException {
090: return new InputStreamReader(
091: ((URLTemplateSource) templateSource).getInputStream(),
092: encoding);
093: }
094:
095: public void closeTemplateSource(Object templateSource)
096: throws IOException {
097: ((URLTemplateSource) templateSource).close();
098: }
099:
100: /**
101: * Can be used by subclasses to canonicalize URL path prefixes.
102: * @param prefix the path prefix to canonicalize
103: * @return the canonicalized prefix. All backslashes are replaced with
104: * forward slashes, and a trailing slash is appended if the original
105: * prefix wasn't empty and didn't already end with a slash.
106: */
107: protected static String canonicalizePrefix(String prefix) {
108: // make it foolproof
109: prefix = prefix.replace('\\', '/');
110: // ensure there's a trailing slash
111: if (prefix.length() > 0 && !prefix.endsWith("/")) {
112: prefix += "/";
113: }
114: return prefix;
115: }
116: }
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