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Created by Dr. Xi on April 29, 2013 09:00:48    Last update: April 29, 2013 09:00:48
In the case proposed by Diony , signing multiple elements by id, simply change the newSignedInfo to: // Create the SignedInfo final List transforms0... I must admit that I don't understand transformations, so take my example code with a grain of salt. Also, signing a doc fragment by PATH does not work, simply because there's no way to identify the fragment with a URI without referring to it by id. Reference ode from org.jcp.xml.dsig.internal.dom.DOMURIDereferencer : // Check if same-document URI and register...
Created by magnum on September 11, 2011 19:46:09    Last update: September 11, 2011 19:46:09
A pair of C functions convert between an Internet address and a string (ASCII): #include <arpa/inet.h> /* * Returns a poin... However , these functions do not support IPv6. The new pair is: #include <arpa/inet.h> /* Convert a Internet ad... Examples: #include <sys/socket.h> #include <netinet/in.h>...
Created by Dr. Xi on June 22, 2011 15:15:15    Last update: June 22, 2011 15:15:15
There's no such thing as an immutable byte array in Java. What we are trying to achieve here is to protect the byte array inside the object from which it is being returned. We want to caller to have the contents of the byte array, but not be able to change the contents inside the object. The trick is to return a copy instead of the internal reference: public class ReturnByteArray { public stati...
Created by alfa on June 02, 2011 15:49:26    Last update: June 02, 2011 15:51:08
Facts: Dynamic proxy classes are generated by the Java runtime, from a list of interfaces given by the user. The generated proxy class implements all interfaces given by the user. The dynamic proxy class is not synthetic . The dynamic proxy class is useless without a user supplied InvocationHandler class, since there's only one constructor for the proxy class and it takes a InvocationHandler as parameter. Example code: import java.lang.reflect.Constructor; import ja... Output: Class: $Proxy0 isSynthetic: false Constructo...
Created by alfa on June 02, 2011 15:26:37    Last update: June 02, 2011 15:26:37
While doing some Java reflection code, I noticed the method Class.isSynthetic() , which the JavaDoc says returns " true if and only if this class is a synthetic class as defined by the Java Language Specification". However, there's no definition of "synthetic class" in the JLS ! The only thing that I can find that remotely resembles a definition is in the JVM spec , where it defines the synthetic attribute : "The Synthetic attribute is a fixed-length attribute in the attributes table of ClassFile (§4.1), field_info (§4.5), and method_info (§4.6) structures. A class member that does not appear in the source code must be marked using a Synthetic attribute." By this definition, a default constructor, which does not appear in the source code, should...
Created by freyo on April 15, 2011 09:00:54    Last update: April 15, 2011 09:00:54
Sample code for writing to a file in the internal storage. There are three steps: Open the file with Context.openFileOutput , which returns java.io.FileOutputStream . Write to the file. Close the file. import java.io.*; import android.content.Contex... The second parameter to openFileOutput is the operating mode. Available values are: Context.MODE_PRIVATE Context.MODE_APPEND Context.MODE_WORLD_READABLE Context.MODE_WORLD_WRITEABLE The file is saved in /data/data/<package_name>/files .
Created by Dr. Xi on October 26, 2010 16:07:40    Last update: October 26, 2010 16:07:40
This is a more generic version, which can be expanded to accommodate additional file signatures. import java.io.*; import java.util.*; pu...
Created by Dr. Xi on August 03, 2010 16:23:55    Last update: October 22, 2010 15:35:20
According to Java documentation: The Java compiler and other Java tools can only process files which contain Latin-1 and/or Unicode-encoded (\udddd notation) characters. This utility converts a utf-8 encoded file to ascii with unicode escape strings for non-ascii characters. import java.io.*; /** * Reads file in U... It is equivalent to: native2ascii -encoding utf-8 using the standard Java native2ascii utility.
Created by Dr. Xi on June 20, 2010 14:35:17    Last update: June 20, 2010 14:35:17
This XML signature validator comes from the Apache XML Security project. It validates the signature according to the core validation processing rules . It does not verify that the key used to generate the signature is a trusted key. You can override the KeySelector class to make sure that the signing key is from a trusted store. import javax.xml.crypto.*; import javax.xml.cry...
Created by Dr. Xi on February 09, 2009 23:14:15    Last update: February 09, 2009 23:14:15
This example demonstrates the general steps in creating a custom Java class loader. Normally a class loader would consult its parent class loader when asked to load a class. If it's not loaded by the parent class loader, then the class loader would try to load the class on its own. This class loader tries to load the requested class on its own first, and delegates to the parent only when a java.lang.SecurityException is thrown (which happens when it tries to load core Java classes such as java.lang.String ). The classes are loaded from CLASSPATH through the getResourceAsStream call. It's important to note that when a class is loaded with a certain class loader, all classes referenced from that class are also loaded through the...
Created by Dr. Xi on October 18, 2008 02:59:57    Last update: October 18, 2008 02:59:57
Use java.sql.PreparedStatement to insert a BLOB or CLOB field: void setAsciiStream(int parameterIndex, InputStream x, int length) Sets the designated parameter to the given input stream, which will have the specified number of bytes. void setBinaryStream(int parameterIndex, InputStream x, int length) Sets the designated parameter to the given input stream, which will have the specified number of bytes. void setCharacterStream(int parameterIndex, Reader reader, int length) Sets the designated parameter to the given Reader object, which is the given number of characters long. void setClob(int i, Clob x) Sets the designated parameter to the given Clob object. void setBlob(int i, Blob x) Sets the designated parameter to the given Blob object. Example code: PreparedStatement pstmt = con.prepareStatement...