| 1 | package org.apache.velocity.runtime.resource.loader; |
| 2 | |
| 3 | /* |
| 4 | * Copyright 2001,2004 The Apache Software Foundation. |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | import java.io.InputStream; |
| 20 | |
| 21 | import org.apache.velocity.runtime.RuntimeServices; |
| 22 | |
| 23 | import org.apache.velocity.runtime.resource.Resource; |
| 24 | |
| 25 | import org.apache.velocity.exception.ResourceNotFoundException; |
| 26 | |
| 27 | import org.apache.commons.collections.ExtendedProperties; |
| 28 | |
| 29 | /** |
| 30 | * This is abstract class the all text resource loaders should |
| 31 | * extend. |
| 32 | * |
| 33 | * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> |
| 34 | * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a> |
| 35 | * @version $Id: ResourceLoader.java,v 1.14.4.1 2004/03/03 23:23:02 geirm Exp $ |
| 36 | */ |
| 37 | public abstract class ResourceLoader |
| 38 | { |
| 39 | /** |
| 40 | * Does this loader want templates produced with it |
| 41 | * cached in the Runtime. |
| 42 | */ |
| 43 | protected boolean isCachingOn = false; |
| 44 | |
| 45 | /** |
| 46 | * This property will be passed on to the templates |
| 47 | * that are created with this loader. |
| 48 | */ |
| 49 | protected long modificationCheckInterval = 2; |
| 50 | |
| 51 | /** |
| 52 | * Class name for this loader, for logging/debuggin |
| 53 | * purposes. |
| 54 | */ |
| 55 | protected String className = null; |
| 56 | |
| 57 | protected RuntimeServices rsvc = null; |
| 58 | |
| 59 | /** |
| 60 | * This initialization is used by all resource |
| 61 | * loaders and must be called to set up common |
| 62 | * properties shared by all resource loaders |
| 63 | */ |
| 64 | public void commonInit( RuntimeServices rs, ExtendedProperties configuration) |
| 65 | { |
| 66 | this.rsvc = rs; |
| 67 | |
| 68 | /* |
| 69 | * these two properties are not required for all loaders. |
| 70 | * For example, for ClasspathLoader, what would cache mean? |
| 71 | * so adding default values which I think are the safest |
| 72 | * |
| 73 | * don't cache, and modCheckInterval irrelevant... |
| 74 | */ |
| 75 | |
| 76 | isCachingOn = configuration.getBoolean("cache", false); |
| 77 | modificationCheckInterval = configuration.getLong("modificationCheckInterval", 0); |
| 78 | |
| 79 | /* |
| 80 | * this is a must! |
| 81 | */ |
| 82 | |
| 83 | className = configuration.getString("class"); |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Initialize the template loader with a |
| 88 | * a resources class. |
| 89 | */ |
| 90 | public abstract void init( ExtendedProperties configuration); |
| 91 | |
| 92 | /** |
| 93 | * Get the InputStream that the Runtime will parse |
| 94 | * to create a template. |
| 95 | */ |
| 96 | public abstract InputStream getResourceStream( String source ) |
| 97 | throws ResourceNotFoundException; |
| 98 | |
| 99 | /** |
| 100 | * Given a template, check to see if the source of InputStream |
| 101 | * has been modified. |
| 102 | */ |
| 103 | public abstract boolean isSourceModified(Resource resource); |
| 104 | |
| 105 | /** |
| 106 | * Get the last modified time of the InputStream source |
| 107 | * that was used to create the template. We need the template |
| 108 | * here because we have to extract the name of the template |
| 109 | * in order to locate the InputStream source. |
| 110 | */ |
| 111 | public abstract long getLastModified(Resource resource); |
| 112 | |
| 113 | /** |
| 114 | * Return the class name of this resource Loader |
| 115 | */ |
| 116 | public String getClassName() |
| 117 | { |
| 118 | return className; |
| 119 | } |
| 120 | |
| 121 | /** |
| 122 | * Set the caching state. If true, then this loader |
| 123 | * would like the Runtime to cache templates that |
| 124 | * have been created with InputStreams provided |
| 125 | * by this loader. |
| 126 | */ |
| 127 | public void setCachingOn(boolean value) |
| 128 | { |
| 129 | isCachingOn = value; |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * The Runtime uses this to find out whether this |
| 134 | * template loader wants the Runtime to cache |
| 135 | * templates created with InputStreams provided |
| 136 | * by this loader. |
| 137 | */ |
| 138 | public boolean isCachingOn() |
| 139 | { |
| 140 | return isCachingOn; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Set the interval at which the InputStream source |
| 145 | * should be checked for modifications. |
| 146 | */ |
| 147 | public void setModificationCheckInterval(long modificationCheckInterval) |
| 148 | { |
| 149 | this.modificationCheckInterval = modificationCheckInterval; |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Get the interval at which the InputStream source |
| 154 | * should be checked for modifications. |
| 155 | */ |
| 156 | public long getModificationCheckInterval() |
| 157 | { |
| 158 | return modificationCheckInterval; |
| 159 | } |
| 160 | } |