141 lines
5.8 KiB
Java
141 lines
5.8 KiB
Java
/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.util;
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import java.io.File;
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import java.io.IOException;
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import java.security.SecureRandom;
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/**
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* Default implementation of the {@link TempFileCreationStrategy} used by {@link TempFile}:
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* Files are collected into one directory and by default are deleted on exit from the VM.
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* Files may be manually deleted by user prior to JVM exit.
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* Files can be kept by defining the system property {@link #KEEP_FILES}.
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*
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* Each file is registered for deletion with the JVM and the temporary directory is not deleted
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* after the JVM exits. Files that are created in the poifiles directory outside
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* the control of DefaultTempFileCreationStrategy are not deleted.
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* See {@link TempFileCreationStrategy} for better strategies for long-running
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* processes or limited temporary storage.
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*/
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public class DefaultTempFileCreationStrategy implements TempFileCreationStrategy {
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/** Define a constant for this property as it is sometimes mistypes as "tempdir" otherwise
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* This is private to avoid having two public-visible constants ({@link TempFile#JAVA_IO_TMPDIR}). */
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private static final String JAVA_IO_TMPDIR = TempFile.JAVA_IO_TMPDIR;
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/*package*/ static final String POIFILES = "poifiles";
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/** To keep files after JVM exit, set the <code>-Dpoi.keep.tmp.files</code> JVM property */
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public static final String KEEP_FILES = "poi.keep.tmp.files";
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/** random number generator to generate unique filenames */
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private static final SecureRandom random = new SecureRandom();
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/** The directory where the temporary files will be created (<code>null</code> to use the default directory). */
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private File dir;
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/**
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* Creates the strategy so that it creates the temporary files in the default directory.
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*
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* @see File#createTempFile(String, String)
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*/
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public DefaultTempFileCreationStrategy() {
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this(null);
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}
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/**
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* Creates the strategy allowing to set the
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*
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* @param dir The directory where the temporary files will be created (<code>null</code> to use the default directory).
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*
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* @see File#createTempFile(String, String, File)
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*/
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public DefaultTempFileCreationStrategy(File dir) {
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this.dir = dir;
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}
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private void createPOIFilesDirectory() throws IOException {
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// Identify and create our temp dir, if needed
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// The directory is not deleted, even if it was created by this TempFileCreationStrategy
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if (dir == null) {
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String tmpDir = System.getProperty(JAVA_IO_TMPDIR);
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if (tmpDir == null) {
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throw new IOException("Systems temporary directory not defined - set the -D"+JAVA_IO_TMPDIR+" jvm property!");
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}
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dir = new File(tmpDir, POIFILES);
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}
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createTempDirectory(dir);
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}
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/**
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* Attempt to create a directory, including any necessary parent directories.
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* Does nothing if directory already exists.
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*
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* @param directory the directory to create
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* @throws IOException if unable to create temporary directory or it is not a directory
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*/
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private void createTempDirectory(File directory) throws IOException {
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// create directory if it doesn't exist
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final boolean dirExists = (directory.exists() || directory.mkdirs());
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if (!dirExists) {
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throw new IOException("Could not create temporary directory '" + directory + "'");
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}
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else if (!directory.isDirectory()) {
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throw new IOException("Could not create temporary directory. '" + directory + "' exists but is not a directory.");
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}
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}
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@Override
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public File createTempFile(String prefix, String suffix) throws IOException {
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// Identify and create our temp dir, if needed
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createPOIFilesDirectory();
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// Generate a unique new filename
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File newFile = File.createTempFile(prefix, suffix, dir);
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// Set the delete on exit flag, unless explicitly disabled
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if (System.getProperty(KEEP_FILES) == null) {
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newFile.deleteOnExit();
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}
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// All done
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return newFile;
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}
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/* (non-JavaDoc) Created directory path is <JAVA_IO_TMPDIR>/poifiles/prefix0123456789 */
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@Override
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public File createTempDirectory(String prefix) throws IOException {
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// Identify and create our temp dir, if needed
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createPOIFilesDirectory();
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// Generate a unique new filename
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// FIXME: Java 7+: use java.nio.Files#createTempDirectory
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final long n = random.nextLong();
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File newDirectory = new File(dir, prefix + Long.toString(n));
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createTempDirectory(newDirectory);
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// Set the delete on exit flag, unless explicitly disabled
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if (System.getProperty(KEEP_FILES) == null) {
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newDirectory.deleteOnExit();
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}
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// All done
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return newDirectory;
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}
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} |