org.springframework.scripting.support.ResourceScriptSource Maven / Gradle / Ivy
/*
* Copyright 2002-2021 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.scripting.support;
import java.io.IOException;
import java.io.Reader;
import java.nio.charset.StandardCharsets;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.lang.Nullable;
import org.springframework.scripting.ScriptSource;
import org.springframework.util.Assert;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.StringUtils;
/**
* {@link org.springframework.scripting.ScriptSource} implementation
* based on Spring's {@link org.springframework.core.io.Resource}
* abstraction. Loads the script text from the underlying Resource's
* {@link org.springframework.core.io.Resource#getFile() File} or
* {@link org.springframework.core.io.Resource#getInputStream() InputStream},
* and tracks the last-modified timestamp of the file (if possible).
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
* @see org.springframework.core.io.Resource#getInputStream()
* @see org.springframework.core.io.Resource#getFile()
* @see org.springframework.core.io.ResourceLoader
*/
public class ResourceScriptSource implements ScriptSource {
/** Logger available to subclasses. */
protected final Log logger = LogFactory.getLog(getClass());
private EncodedResource resource;
private long lastModified = -1;
private final Object lastModifiedMonitor = new Object();
/**
* Create a new ResourceScriptSource for the given resource.
* @param resource the EncodedResource to load the script from
*/
public ResourceScriptSource(EncodedResource resource) {
Assert.notNull(resource, "Resource must not be null");
this.resource = resource;
}
/**
* Create a new ResourceScriptSource for the given resource.
* @param resource the Resource to load the script from (using UTF-8 encoding)
*/
public ResourceScriptSource(Resource resource) {
Assert.notNull(resource, "Resource must not be null");
this.resource = new EncodedResource(resource, StandardCharsets.UTF_8);
}
/**
* Return the {@link org.springframework.core.io.Resource} to load the
* script from.
*/
public final Resource getResource() {
return this.resource.getResource();
}
/**
* Set the encoding used for reading the script resource.
* The default value for regular Resources is "UTF-8".
* A {@code null} value implies the platform default.
*/
public void setEncoding(@Nullable String encoding) {
this.resource = new EncodedResource(this.resource.getResource(), encoding);
}
@Override
public String getScriptAsString() throws IOException {
synchronized (this.lastModifiedMonitor) {
this.lastModified = retrieveLastModifiedTime();
}
Reader reader = this.resource.getReader();
return FileCopyUtils.copyToString(reader);
}
@Override
public boolean isModified() {
synchronized (this.lastModifiedMonitor) {
return (this.lastModified < 0 || retrieveLastModifiedTime() > this.lastModified);
}
}
/**
* Retrieve the current last-modified timestamp of the underlying resource.
* @return the current timestamp, or 0 if not determinable
*/
protected long retrieveLastModifiedTime() {
try {
return getResource().lastModified();
}
catch (IOException ex) {
if (logger.isDebugEnabled()) {
logger.debug(getResource() + " could not be resolved in the file system - " +
"current timestamp not available for script modification check", ex);
}
return 0;
}
}
@Override
@Nullable
public String suggestedClassName() {
String filename = getResource().getFilename();
return (filename != null ? StringUtils.stripFilenameExtension(filename) : null);
}
@Override
public String toString() {
return this.resource.toString();
}
}