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From "Steven Dodd" <steven.d...@practiv.com>
Subject IterateHash Task - HashMap
Date Tue, 04 Nov 2003 08:30:00 GMT
Hi,

I have created a new task based on a task submitted to this list by Alan
Peng http://marc.theaimsgroup.com/?l=ant-dev&m=100525765020413&w=2

If you think of Alan's task as a foreach loop or an array of property
values you can think of mine as a hashmap iterator - hence the name
iterateHash.

I have used this task to combine document root's, for application
servers with multiple applications, to deploy to web servers for serving
static content...  

In this example I create a comma separated list of 'keys' or what will
be contextRoots - and then define the src directories containing the
content, by mapping the key to a value.

<taskdef name="iterateHash"
classname="org.apache.tools.ant.taskdefs.IterateHash"/>

<property name="keys" value="app1,app2,app3"/>
<property name="appn1" value="applications/app1/web-app"/>
<property name="appn2" value="applications/app2/web-app"/>
<property name="appn3" value="applications/niceApp/web-app"/>

I then can call a target '-combineDocRoot' repeatedly each time setting
the 'key' to a context root and the 'value' to the src directory.

<iterateHash key="key" value="value" itemList="keys"
target="-combineDocRoot"/>

Where 
      key      = the name of the ant property to set as the key
      value    = the name of the ant property to set as the value
      itemList = the list of keys (perhaps might be better named
keyIndex)
      target   = the name of the ant target to call foreach key/value
pair

<target name="-combineDocRoot" description="Incrementally combines
docroots">
  <mkdir dir="${docRoot}/${key}"/>
  <copy todir="${docRoot}/${key}">
    <fileset dir="${value}"/>
  </copy>
</target>

Source code below - enjoy :)


package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.Task;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.taskdefs.Ant;
import org.apache.tools.ant.taskdefs.Property;
import java.util.Map;
import java.util.Iterator;
import java.util.StringTokenizer;

/** This class is a Jakarta Ant custom task that repeatedly calls a
target
 * passing different key/value pair from a delimited string.
 *
 * <p>For example:
 * <pre>
 * &lt;project name="Ant_Extensions" default="main" basedir="."&gt;
 *   &lt;taskdef name="iterate"
classname="org.apache.tools.ant.taskdefs.Iterate"/&gt;
 *
 *   &lt;target name="main"&gt;
 *     &lt;iterate target="hello" itemList="one,two,three" key="i"
value="j"&gt;
 *     &lt;/iterate&gt;
 *     &lt;property name="one" value="1"/&gt;
 *     &lt;property name="two" value="2"/&gt;
 *     &lt;property name="three" value="3"/&gt;
 *   &lt;/target&gt;
 *
 *   &lt;target name="hello"&gt;
 *     &lt;echo message="${i}" = "${j}" /&gt;
 *   &lt;/target&gt;
 * &lt;/project&gt;
 * </pre>
 *
 * <p>The above example will call the hello target three times, each
time
 * passing a key/value pair. In this case the hello target will
 * echo one = 1, then two = 2 and then three = 3.
 *
 * <p>List of attributes:
 * <table border>
 * <tr><th>Attribute</th><th>Description</th><th>Required</th></tr>
 * <tr><td>target</td><td>This is the name of the target to
call.</td><td>Yes</td></tr>
 * <tr><td>key</td><td>The name of the key in which each value from
the
item list will be 
 * stored for each iteration.</td><td>Yes</td></tr>
 * <tr><td>value</td><td>The name of the value in which each value
from
the item list will 
 * be stored for each iteration.</td><td>Yes</td></tr>
 * <tr><td>itemList</td><td>A delimited list of items
strings.</td><td>Yes</td></tr>
 * <tr><td>iheritAll</td><td>Boolean to enable/disable the called
target
from inheriting all 
 * the properties from the environment.</td><td>No</td></tr>
 * <tr><td>delimiter</td><td>The delimiter that is used to delimited
the
strings in the 
 * item list.</td><td>No</td></tr>
 * </table>
 * @author Steven Dodd, steven.dodd@practiv.com
 */
public class IterateHash extends Task {

  /** Default constructor.
   */
  public IterateHash() {}

  /** Set the item list string. The item list can contain one or more
   *  delimited strings. The specified target will be called once for
each
   *  string in the item list.
   *
   *  <p>The delimiter can be changed by specifying the
   *  delimiter attribute.
   *
   * @param pItemList Delimited string of items.
   */
  public void setItemList(String pItemList) {
    mItemList = pItemList;
  }

  /** Set the Ant target name that will be called repeatedly, once for
each
   *  item in the item list.
   *
   * @param pTargetName The name of the target to call repeatedly.
   */
  public void setTarget(String pTargetName) {
    mTargetName = pTargetName;
  }

  /** Sets the inherit all flag. If the value is true, then the target
that
   *  is called will inherit all the properties. Default is true.
   *
   * @param pInheritAll Inherit flag.
   */
  public void setInheritAll(boolean pInheritAll) {
    mInheritAll = pInheritAll;
  }

  /** Set the Key. The key attribute is the name of the property
   *  that will contain each key in the item hash.
   *
   * @param pKey Key Name
   */
  public void setKey(String pKey) {
    mKey = pKey;
  }

  /** Set the Value. The value attribute is the name of the property
   *  that will contain each value in the item hash.
   *
   * @param pValue Value Name
   */
  public void setValue(String pValue) {
    mValue = pValue;
  }

  /** Set the delimiter that will be used to delimit the strings in the
item
   *  list, the default is comma ",".
   *
   * @param pDelimiter Delimiter charater.
   */
  public void setDelimiter(String pDelimiter) {
    mDelimiter = pDelimiter;
  }

  /** Ant execute service method, called when the task is executed.
   *
   * @exception BuildException When required attributes are not set
   */
  public void execute() throws BuildException {

    if (mTargetName == null || mTargetName.equals("")) {
      throw new BuildException("Attribute target is required.",
location);
    }

    if (mKey == null || mKey.equals("")) {
      throw new BuildException("Attribute key is required.", location);
    }

    if (mValue == null || mValue.equals("")) {
      throw new BuildException("Attribute value is required.",
location);
    }

    if (mItemList == null || mItemList.equals("")) {
      throw new BuildException("Attribute itemList is required.",
location);
    }

    // initialise the target
    mTarget.setDir(project.getBaseDir());
    mTarget.setAntfile(project.getProperty("ant.file"));
    mTarget.setTarget(mTargetName);
    mTarget.setInheritAll(mInheritAll);

    // set key/value and then call the target for each item in the item
list
    mItemList = project.getProperty(mItemList);
    StringTokenizer st = new StringTokenizer(mItemList, mDelimiter);
    while (st.hasMoreTokens()) {
      String p = st.nextToken().trim();

      // Set the key value
      project.setProperty(mKey, p);
      log("Set key:" + mKey + " to " + p);

      // Get the value property or set to null if not defined
      p = project.getProperty(p);

      // If the key/value pair is aviable set the value property
      // and then execute the target
      if (p != null) {
        project.setProperty(mValue, p);
        log("Set value:" + mValue + " to " + p);
        mTarget.execute();

      } else {
        log("Could not find value - will not execute target");
      }
    }
  }

  /** Ant init service method, to initialise the task.
   *
   * @exception BuildException Build exception.
   */
  public void init() throws BuildException {
    super.init();

    // initialise the called target
    mTarget = (Ant) project.createTask("ant");
    mTarget.setOwningTarget(target);
    mTarget.setTaskName(getTaskName());
    mTarget.setLocation(location);
    mTarget.init();
  }

  /** Ant create param service method, which is called for each 
   * embedded param element.
   *
   * @return Property object.
   */
  public Property createParam() {
    return mTarget.createProperty();
  }

  private void dumpProperties() {

    Map values = project.getProperties();
    Iterator i = values.entrySet().iterator();

    while(i.hasNext()) {
      System.out.println(i.next());
    }
  }

  private String mItemList;
  private String mTargetName;
  private boolean mInheritAll = true;
  private Ant mTarget;
  private String mKey;
  private String mValue;
  private String mDelimiter = ",";

}


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