Spring Framework example source code file (ResourceScriptSource.java)

This example Spring Framework source code file (ResourceScriptSource.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

could, filereader, inputstreamreader, io, ioexception, ioexception, object, object, reader, resource, resource, resourcescriptsource, scriptsource, string, string

The Spring Framework ResourceScriptSource.java source code

/*
 * Copyright 2002-2008 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
 *
 *      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 org.springframework.scripting.support;

import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;

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

import org.springframework.core.io.Resource;
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 final Resource resource;

	private long lastModified = -1;

	private final Object lastModifiedMonitor = new Object();


	/**
	 * Create a new ResourceScriptSource for the given resource.
	 * @param resource the Resource to load the script from
	 */
	public ResourceScriptSource(Resource resource) {
		Assert.notNull(resource, "Resource must not be null");
		this.resource = resource;
	}

	/**
	 * Return the {@link org.springframework.core.io.Resource} to load the
	 * script from.
	 */
	public final Resource getResource() {
		return this.resource;
	}


	public String getScriptAsString() throws IOException {
		synchronized (this.lastModifiedMonitor) {
			this.lastModified = retrieveLastModifiedTime();
		}
		Reader reader = null;
		try {
			// Try to get a FileReader first: generally more reliable.
			reader = new FileReader(getResource().getFile());
		}
		catch (IOException ex) {
			if (logger.isDebugEnabled()) {
				logger.debug("Could not open FileReader for " + this.resource +
						" - falling back to InputStreamReader", ex);
			}
		}
		if (reader == null) {
			reader = new InputStreamReader(this.resource.getInputStream());
		}
		return FileCopyUtils.copyToString(reader);
	}

	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;
		}
	}

	public String suggestedClassName() {
		return StringUtils.stripFilenameExtension(getResource().getFilename());
	}


	public String toString() {
		return this.resource.toString();
	}

}