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Diffstat (limited to 'framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/ChecksumAlgorithm.java')
-rw-r--r-- | framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/ChecksumAlgorithm.java | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/ChecksumAlgorithm.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/ChecksumAlgorithm.java new file mode 100644 index 00000000..210d5dc9 --- /dev/null +++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/ChecksumAlgorithm.java @@ -0,0 +1,151 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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.apache.tools.ant.types.selectors.modifiedselector; + +import java.io.BufferedInputStream; +import java.io.File; +import java.io.FileInputStream; +import java.security.NoSuchAlgorithmException; +import java.util.Locale; +import java.util.zip.Adler32; +import java.util.zip.CRC32; +import java.util.zip.CheckedInputStream; +import java.util.zip.Checksum; + +import org.apache.tools.ant.BuildException; + + +/** + * Computes a 'checksum' for the content of file using + * java.util.zip.CRC32 and java.util.zip.Adler32. + * Use of this algorithm doesn't require any additional nested <param>s. + * Supported <param>s are: + * <table> + * <tr> + * <th>name</th><th>values</th><th>description</th><th>required</th> + * </tr> + * <tr> + * <td> algorithm.algorithm </td> + * <td> ADLER | CRC ( default ) </td> + * <td> name of the algorithm the checksum should use </td> + * <td> no, defaults to CRC </td> + * </tr> + * </table> + * + * @version 2004-06-17 + * @since Ant 1.7 + */ +public class ChecksumAlgorithm implements Algorithm { + + + // ----- member variables ----- + + + /** + * Checksum algorithm to be used. + */ + private String algorithm = "CRC"; + + /** + * Checksum interface instance + */ + private Checksum checksum = null; + + + // ----- Algorithm-Configuration ----- + + + /** + * Specifies the algorithm to be used to compute the checksum. + * Defaults to "CRC". Other popular algorithms like "ADLER" may be used as well. + * @param algorithm the digest algorithm to use + */ + public void setAlgorithm(String algorithm) { + this.algorithm = + algorithm != null ? algorithm.toUpperCase(Locale.ENGLISH) : null; + } + + + /** Initialize the checksum interface. */ + public void initChecksum() { + if (checksum != null) { + return; + } + if ("CRC".equals(algorithm)) { + checksum = new CRC32(); + } else if ("ADLER".equals(algorithm)) { + checksum = new Adler32(); + } else { + throw new BuildException(new NoSuchAlgorithmException()); + } + } + + + // ----- Logic ----- + + + /** + * This algorithm supports only CRC and Adler. + * @return <i>true</i> if all is ok, otherwise <i>false</i>. + */ + public boolean isValid() { + return "CRC".equals(algorithm) || "ADLER".equals(algorithm); + } + + + /** + * Computes a value for a file content with the specified checksum algorithm. + * @param file File object for which the value should be evaluated. + * @return The value for that file + */ + public String getValue(File file) { + initChecksum(); + String rval = null; + + try { + if (file.canRead()) { + checksum.reset(); + FileInputStream fis = new FileInputStream(file); + CheckedInputStream check = new CheckedInputStream(fis, checksum); + BufferedInputStream in = new BufferedInputStream(check); + while (in.read() != -1) { + // Read the file + } + rval = Long.toString(check.getChecksum().getValue()); + in.close(); + } + } catch (Exception e) { + rval = null; + } + return rval; + } + + + /** + * Override Object.toString(). + * @return some information about this algorithm. + */ + public String toString() { + StringBuilder buf = new StringBuilder(); + buf.append("<ChecksumAlgorithm:"); + buf.append("algorithm=").append(algorithm); + buf.append(">"); + return buf.toString(); + } +} |