Transcript CVS / Ant

CMSC 341
Java Packages
Ant
CVS
Project Submission
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Packages
• Java packages create libraries
– A group of classes organized together into a
single namespace.
– Allows multiple classes with the same name
• MyPackage.Stack
• YourPackage.Stack
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Packages
• A file may belong to only one package.
• Packages serve as a namespace in Java and
create a directory hierarchy when compiled.
• Classes are placed in a package using the
following syntax in the first line that is not a
comment.
package packagename;
package packagename.subpackagename;
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Multiple Stack Classes
// My stack.java file
package MyPackage;
public class Stack
{
// …
};
// Your stack.java file
package YourPackage;
public class Stack
{
// …
};
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Packages (cont.)
• The fully qualified name of a class is the
packageName.ClassName.
java.lang.String
MyPackage.Stack
YourPackage.Stack
• To alleviate the burden of using the fully qualified
name of a class, use an import statement before the
class declaration.
import
import
import
import
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java.util.StringBuffer;
java.util.*;
MyPackage.Stack;
YourPackage.*;
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Packages (cont.)
• It is common practice to duplicate the package directory
hierarchy in a directory named src and to compile to a
directory named bin.
• Create this directory manually in your GL account
– Eclipse creates this directory structure for you
Project1
Root of project directory tree
src
proj1
Package name
Example.java
proj1
Package name
bin
Example.class
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Compiling with packages
• When using the Unix command line, classes in a package are
compiled using the –d option.
• Given the directory structure on the previous slide, run the
command below from the src directory to compile the code
from the Project1/src directory to the Project1/bin
directory.
• The -d switch tells the compiler where to place the .class file
• The bin directory must exist before compiling. The compiler
will create the proj1 directory under bin.
javac –d ../bin proj1/Example.java
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Packages and Eclipse
• By default Eclipse automatically creates a
src/ directory when you create a new Java
Project
• Eclipse will then automatically create a bin/
directory and associated package directory
hierarchy when it compiles your Java classes
– Note: the bin/ directory tree is hidden by Eclipse
when in the Java perspective, but you can see it if
viewing the file system.
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What is Ant?
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Ant is a Java based tool for automating the build process
Platform independent commands (works on Windows,
Mac & Unix)
XML based format
Easily extendable using Java classes
Ant is an open source (free) Apache project
Ant files used in this course require the package
directory structure described earlier
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Anatomy of a Build File
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Ant’s build files are written in XML
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Each build file contains
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A project
At least 1 target
Targets are composed of some number of tasks
Build files may also contain properties
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Convention is to call file build.xml
Like macros in a make file
Comments are within <!-- --> blocks
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Projects
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The project tag is used to define the project
to which the ANT file applies
Projects tags typically contain 3 attributes
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name – a logical name for the project
default – the default target to execute
basedir – the base directory relative to which all
operations are performed
Additionally, a description for the project can
be specified from within the project tag
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Project tag
<project name="Sample Project" default="compile"
basedir=".">
<description>
A sample build file for this project
Recall that “.” (dot) refers to the current
directory
</description>
</project>
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Properties
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Build files may contain constants (known as
properties) to assign a value to a variable which can
then be used throughout the project
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Makes maintaining large build files more manageable and
easily changeable
Projects can have a set of properties
• Property tags consist of a name/value pair
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Use the property names throughout the build file
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The value is substituted for the name when the build file is
“executed”
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Build File with Properties
<project name="Sample Project" default="compile"
basedir=".">
<description>
A sample build file for this project
</description>
<!-- global properties (constants) for this build
file -->
<property name="source.dir" location="src"/>
<property name="build.dir" location="bin"/>
<property name="doc.dir" location="doc"/>
</project>
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Tasks
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A task represents an action that needs execution
Tasks have a variable number of attributes
which are task dependant
There are a number of built-in tasks, most of
which are things which you would typically do as
part of a build process
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mkdir - create a directory
javac - compile java source code
java - execute a Java .class file
javadoc - run the javadoc tool over some files
And many, many others…
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For a full list see:
http://ant.apache.org/manual/tasksoverview.html
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Targets
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The target tag has the following required attribute
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Targets may also have optional attributes such as
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depends – a list of other target names for which this task is
dependant upon, the specified task(s) get executed first
description – a description of what a target does
Targets in Ant can depend on some number of other
targets
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name – the logical name for a target
For example, we might have a target to create a jarfile, which first
depends upon another target to compile the code
Targets contain a list of tasks to be executed
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Build File with Targets
<project name="Sample Project" default="compile" basedir=".">
<!-- set up some directories used by this project -->
<target name="init" description="setup project directories">
<!-- list of tasks to be executed -->
</target>
<!-- Compile the java code in src dir into build dir -->
<target name="compile" depends="init" description="compile java sources">
<!-- list of tasks to be executed -->
</target>
<!-- Generate javadocs for current project into docs dir -->
<target name="doc" depends="init" description="generate documentation">
<!-- list of tasks to be executed -->
</target>
<!-- Execute main in the specified class under ${build.dir} -->
<target name=”run" depends=“compile” description=”run the application">
<!-- list of tasks to be executed -->
</target>
<!-- Delete the build & doc directories and Emacs backup (*~) files -->
<target name="clean" description="tidy up the workspace">
<!-- list of tasks to be executed -->
</target>
</project>
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Initialization Target & Tasks
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Our initialization target creates the build and
documentation directories
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The mkdir task creates a directory
<project name="Sample Project" default="compile" basedir=".">
...
<!-- set up some directories used by this project -->
<target name="init" description="setup project directories">
<mkdir dir="${build.dir}"/>
<mkdir dir="${doc.dir}"/>
</target>
...
</project>
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Compilation Target & Tasks
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Our compilation target will compile all java files in the source
directory
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The javac task compiles sources into classes
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Note the dependence on the init task
<project name="Sample Project" default="compile" basedir=".">
...
<!-- Compile the java code in ${src.dir} into ${build.dir} -->
<target name="compile" depends="init" description="compile java
sources">
<javac srcdir="${source.dir}" destdir="${build.dir}"/>
</target>
...
</project>
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Run Target & Tasks
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Our run target will execute main in the fully specified class
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Typically dependent on the compile task
<project name="Sample Project" default="compile" basedir=".">
...
<!-- Execute main in the fully qualified name under
${build.dir} -->
<target name=”run" depends=”compile" description=“run the
application">
<java directory=“${build.dir}” classname=“${main.class}”
fork=“yes”>
<arg line=“${args}” />
</java>
</target>
...
</project>
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Running Ant – Command Line
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Move into the directory which contains the build.xml file
Type ant followed by the name of a target
unix> ant run
unix> ant compile
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Type ant at the unix prompt to run the project’s default
target -- see screen shot on next page
unix> ant
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Ant screen snapshot
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Project Submission
• Projects in this course will be submitted
electronically through the use of an industry
standard version control system named CVS.
• CVS can be used from the Unix command
line, or from an Eclipse perspective.
• In either case, we must be familiar with Java
packages and their associated directory
structure as discussed earlier.
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What is CVS?
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Concurrent Versioning System (CVS) is one of
the earlier SCM systems which gained wide
adoption
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Open source
Easy to install and use
Simple command line client
Wide integration in a lot of development tools
Used for submitting projects in this course
For good introduction on version control and CVS
see the following book…
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Pragmatic Version Control using CVS
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CVS Terminology
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Repository – the place where resources (files) are
stored
Checkout – copy resources from the repository and
create a working copy
Checkin/Commit – place resources from your
working copy into the repository
Add – place a resource under version control
Remove – delete a resource from version control
Update – pull down changes from the repository into
your working copy
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Using CVS in this course
• See
http://www.cs.umbc.edu/courses/undergradu
ate/341/fall12/projects/CVS.html
• For additional slides about CVS submission
via Eclipse:
http://www.cs.umbc.edu/courses/undergraduat
e/341/Lectures/CVS/intro-to-cvs.ppt
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