diff --git a/build.xml b/build.xml
index 4578c22ec..d3e8d818a 100644
--- a/build.xml
+++ b/build.xml
@@ -89,7 +89,7 @@
          Check to see what optional dependencies are available              
        =================================================================== 
   -->
-  <target name="check_for_optional_packages_1">
+  <target name="check_for_optional_packages">
     <available property="jdk1.2+" classname="java.lang.ThreadLocal" />
     <available property="jdk1.3+" classname="java.lang.StrictMath" />
     <available property="jdk1.4+" classname="java.lang.CharSequence" />
@@ -147,22 +147,18 @@
     <available property="jdepend.present" 
                classname="jdepend.framework.JDepend"  
                classpathref="classpath"/>
-    <available property="jaf.present"
-               classname="javax.activation.DataHandler"
-               classpathref="classpath"/>
     <available property="log4j.present"
                classname="org.apache.log4j.Category"
                classpathref="classpath"/>
                
-  </target>
-
-  <target name="check_for_optional_packages" 
-          depends="check_for_optional_packages_1"
-          if="jaf.present">
-    <available property="javamail.complete"
-               classname="javax.mail.Transport"
-               classpathref="classpath"/>
-               
+    <condition property="javamail.complete">
+      <and>
+        <available classname="javax.activation.DataHandler"
+                   classpathref="classpath"/>
+        <available classname="javax.mail.Transport"
+                   classpathref="classpath"/>
+      </and>
+    </condition>
   </target>
 
   <!-- 
diff --git a/src/main/org/apache/tools/ant/AntClassLoader.java b/src/main/org/apache/tools/ant/AntClassLoader.java
index 8daa2ba4d..bb329a19e 100644
--- a/src/main/org/apache/tools/ant/AntClassLoader.java
+++ b/src/main/org/apache/tools/ant/AntClassLoader.java
@@ -237,7 +237,7 @@ public class AntClassLoader extends ClassLoader implements BuildListener {
     /**
      * Create a classloader for the given project using the classpath given.
      *
-     * @param project the project to ehich this classloader is to belong.
+     * @param project the project to which this classloader is to belong.
      * @param classpath the classpath to use to load the classes.  This
      *                is combined with the system classpath in a manner
      *                determined by the value of ${build.sysclasspath}
diff --git a/src/main/org/apache/tools/ant/TaskAdapter.java b/src/main/org/apache/tools/ant/TaskAdapter.java
index 557bc14ee..1de409811 100644
--- a/src/main/org/apache/tools/ant/TaskAdapter.java
+++ b/src/main/org/apache/tools/ant/TaskAdapter.java
@@ -71,6 +71,21 @@ public class TaskAdapter extends Task {
      * Do the execution.
      */
     public void execute() throws BuildException {
+        Method setProjectM = null;
+        try {
+            Class c = proxy.getClass();
+            setProjectM = 
+                c.getMethod( "setProject", new Class[] {Project.class});
+            if(setProjectM != null) {
+                setProjectM.invoke(proxy, new Object[] {project});
+            }
+        } catch( Exception ex ) {
+            log("Error setting project in " + proxy.getClass(), 
+                Project.MSG_ERR);
+            throw new BuildException( ex );
+        }
+
+
         Method executeM=null;
         try {
             Class c=proxy.getClass();
diff --git a/src/main/org/apache/tools/ant/taskdefs/Available.java b/src/main/org/apache/tools/ant/taskdefs/Available.java
index e001f14c6..c965e8b4e 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Available.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Available.java
@@ -57,6 +57,7 @@ package org.apache.tools.ant.taskdefs;
 import java.io.*;
 import java.util.*;
 import org.apache.tools.ant.*;
+import org.apache.tools.ant.taskdefs.condition.Condition;
 import org.apache.tools.ant.types.*;
 
 /**
@@ -65,7 +66,7 @@ import org.apache.tools.ant.types.*;
  * @author Stefano Mazzocchi <a href="mailto:stefano@apache.org">stefano@apache.org</a>
  */
 
-public class Available extends Task {
+public class Available extends Task implements Condition {
 
     private String property;
     private String classname;
@@ -133,7 +134,13 @@ public class Available extends Task {
         if (property == null) {
             throw new BuildException("property attribute is required", location);
         }
+
+        if (eval()) {
+            this.project.setProperty(property, value);
+        }
+    }
         
+    public boolean  eval() throws BuildException {
         if (classname == null && file == null && resource == null) {
             throw new BuildException("At least one of (classname|file|resource) is required", location);
         }
@@ -145,28 +152,30 @@ public class Available extends Task {
         }
 
         if (classpath != null) {
+            classpath.setProject(project);
             this.loader = new AntClassLoader(project, classpath);
         }
 
         if ((classname != null) && !checkClass(classname)) {
             log("Unable to load class " + classname + " to set property " + property, Project.MSG_VERBOSE);
-            return;
+            return false;
         }
         
         if ((file != null) && !checkFile()) {
             log("Unable to find " + file + " to set property " + property, Project.MSG_VERBOSE);
-            return;
+            return false;
         }
         
         if ((resource != null) && !checkResource(resource)) {
             log("Unable to load resource " + resource + " to set property " + property, Project.MSG_VERBOSE);
-            return;
+            return false;
         }
 
-        this.project.setProperty(property, value);
         if (loader != null) {
             loader.cleanup();
         }
+
+        return true;
     }
 
     private boolean checkFile() {
diff --git a/src/main/org/apache/tools/ant/taskdefs/ConditionTask.java b/src/main/org/apache/tools/ant/taskdefs/ConditionTask.java
new file mode 100644
index 000000000..9c674763e
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/ConditionTask.java
@@ -0,0 +1,110 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs;
+
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.taskdefs.condition.Condition;
+import org.apache.tools.ant.taskdefs.condition.ConditionBase;
+
+/**
+ * &lt;condition&gt; task as a generalization of &lt;available&gt; and
+ * &lt;uptodate&gt;
+ *
+ * <p>This task supports boolean logic as well as pluggable conditions
+ * to decide, whether a property should be set.</p>
+ *
+ * <p>This task does not extend Task to take advantage of
+ * ConditionBase.</p>
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class ConditionTask extends ConditionBase {
+
+    private String property;
+    private String value = "true";
+
+    /**
+     * The name of the property to set. Required.
+     *
+     * @since 1.1
+     */
+    public void setProperty(String p) {property = p;}
+
+    /**
+     * The value for the property to set. Defaults to "true".
+     *
+     * @since 1.1
+     */
+    public void setValue(String v) {value = v;}
+
+    /**
+     * See whether our nested condition holds and set the property.
+     *
+     * @since 1.1
+     */
+    public void execute() throws BuildException {
+        if (countConditions() > 1) {
+            throw new BuildException("You must not nest more than one condition into <condition>");
+        }
+        if (countConditions() < 1) {
+            throw new BuildException("You must nest a condition into <condition>");
+        }
+        Condition c = (Condition) getConditions().nextElement();
+        if (c.eval()) {
+            getProject().setProperty(property, value);
+        }
+    }
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/UpToDate.java b/src/main/org/apache/tools/ant/taskdefs/UpToDate.java
index 33ed1098b..9fbbea633 100644
--- a/src/main/org/apache/tools/ant/taskdefs/UpToDate.java
+++ b/src/main/org/apache/tools/ant/taskdefs/UpToDate.java
@@ -55,6 +55,7 @@
 package org.apache.tools.ant.taskdefs;
 
 import org.apache.tools.ant.*;
+import org.apache.tools.ant.taskdefs.condition.Condition;
 import org.apache.tools.ant.types.*;
 import org.apache.tools.ant.util.*;
 import java.io.*;
@@ -71,7 +72,7 @@ import java.util.Vector;
  * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a>
  */
 
-public class UpToDate extends MatchingTask {
+public class UpToDate extends MatchingTask implements Condition {
 
     private String _property;
     private String _value;
@@ -137,11 +138,9 @@ public class UpToDate extends MatchingTask {
     }
 
     /**
-     * Sets property to true if target files have a more recent timestamp than
-     * each of the corresponding source files.
+     * Evaluate all target and source files, see if the targets are up-to-date.
      */
-    public void execute() throws BuildException {
-
+    public boolean eval() {
         if (sourceFileSets.size() == 0) {
           throw new BuildException("At least one <srcfiles> element must be set");
         }
@@ -151,7 +150,7 @@ public class UpToDate extends MatchingTask {
         }
 
         // if not there then it can't be up to date
-        if (_targetFile != null && !_targetFile.exists()) return; 
+        if (_targetFile != null && !_targetFile.exists()) return false; 
 
         Enumeration enum = sourceFileSets.elements();
         boolean upToDate = true;
@@ -161,7 +160,16 @@ public class UpToDate extends MatchingTask {
             upToDate = upToDate && scanDir(fs.getDir(project), 
                                            ds.getIncludedFiles());
         }
+        return upToDate;
+    }
+
 
+    /**
+     * Sets property to true if target files have a more recent timestamp than
+     * each of the corresponding source files.
+     */
+    public void execute() throws BuildException {
+        boolean upToDate = eval();
         if (upToDate) {
             this.project.setProperty(_property, this.getValue());
             if (mapperElement == null) {
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/And.java b/src/main/org/apache/tools/ant/taskdefs/condition/And.java
new file mode 100644
index 000000000..2c04b8024
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/And.java
@@ -0,0 +1,83 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import java.util.Enumeration;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * &lt;and&gt; condition container.
+ *
+ * <p>Iterates over all conditions and returns false as soon as one
+ * evaluates to false.</p>
+ * 
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class And extends ConditionBase implements Condition {
+
+    public boolean eval() throws BuildException {
+        Enumeration enum = getConditions();
+        while (enum.hasMoreElements()) {
+            Condition c = (Condition) enum.nextElement();
+            if (!c.eval()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Condition.java b/src/main/org/apache/tools/ant/taskdefs/condition/Condition.java
new file mode 100644
index 000000000..a2028d375
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Condition.java
@@ -0,0 +1,71 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * Interface for conditions to use inside the &lt;condition&gt; task.
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public interface Condition {
+    /**
+     * Is this condition true?
+     */
+    public boolean eval() throws BuildException;
+}
+
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/ConditionBase.java b/src/main/org/apache/tools/ant/taskdefs/condition/ConditionBase.java
new file mode 100644
index 000000000..adbd07c71
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/ConditionBase.java
@@ -0,0 +1,177 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+import java.util.Vector;
+
+import org.apache.tools.ant.Project;
+import org.apache.tools.ant.Task;
+import org.apache.tools.ant.taskdefs.Available;
+import org.apache.tools.ant.taskdefs.UpToDate;
+
+/**
+ * Baseclass for the &lt;condition&gt; task as well as several
+ * conditions - ensures that the types of conditions inside the task
+ * and the "container" conditions are in sync.
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public abstract class ConditionBase {
+    private Vector conditions = new Vector();
+    private Project project;
+
+    public void setProject(Project p) {
+        this.project = p;
+    }
+    protected Project getProject() {return project;}
+
+    /**
+     * Count the conditions.
+     *
+     * @since 1.1
+     */
+    protected int countConditions() {return conditions.size();}
+
+    /**
+     * Iterate through all conditions.
+     *
+     * @since 1.1
+     */
+    protected final Enumeration getConditions() {
+        return new ConditionEnumeration();
+    }
+
+    /**
+     * Add an &lt;available&gt; condition.
+     *
+     * @since 1.1
+     */
+    public void addAvailable(Available a) {conditions.addElement(a);}
+
+    /**
+     * Add an &lt;uptodate&gt; condition.
+     *
+     * @since 1.1
+     */
+    public void addUptodate(UpToDate u) {conditions.addElement(u);}
+
+    /**
+     * Add an &lt;not&gt; condition "container".
+     *
+     * @since 1.1
+     */
+    public void addNot(Not n) {conditions.addElement(n);}
+
+    /**
+     * Add an &lt;and&gt; condition "container".
+     *
+     * @since 1.1
+     */
+    public void addAnd(And a) {conditions.addElement(a);}
+
+    /**
+     * Add an &lt;or&gt; condition "container".
+     *
+     * @since 1.1
+     */
+    public void addOr(Or o) {conditions.addElement(o);}
+
+    /**
+     * Add an &lt;equals&gt; condition.
+     *
+     * @since 1.1
+     */
+    public void addEquals(Equals e) {conditions.addElement(e);}
+
+    /**
+     * Add an &lt;os&gt; condition.
+     *
+     * @since 1.1
+     */
+    public void addOs(Os o) {conditions.addElement(o);}
+
+    /**
+     * Inner class that configures those conditions with a project
+     * instance that need it.
+     *
+     * @since 1.1
+     */
+    private class ConditionEnumeration implements Enumeration {
+        private int currentElement = 0;
+
+        public boolean hasMoreElements() {
+            return countConditions() > currentElement;
+        }
+
+        public Object nextElement() throws NoSuchElementException {
+            Object o = null;
+            try {
+                o = conditions.elementAt(currentElement++);
+            } catch (ArrayIndexOutOfBoundsException e) {
+                throw new NoSuchElementException();
+            }
+            
+            if (o instanceof Task) {
+                ((Task) o).setProject(getProject());
+            } else if (o instanceof ConditionBase) {
+                ((ConditionBase) o).setProject(getProject());
+            }
+            return o;
+        }
+    }
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Equals.java b/src/main/org/apache/tools/ant/taskdefs/condition/Equals.java
new file mode 100644
index 000000000..e8ca6ffcc
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Equals.java
@@ -0,0 +1,78 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * Simple String comparison condition.
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class Equals implements Condition {
+
+    private String arg1, arg2;
+
+    public void setArg1(String a1) {arg1 = a1;}
+    public void setArg2(String a2) {arg2 = a2;}
+
+    public boolean eval() throws BuildException {
+        if (arg1 == null || arg2 == null) {
+            throw new BuildException("both arg1 and arg2 are required in equals");
+        }
+        return arg1.equals(arg2);
+    }
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Not.java b/src/main/org/apache/tools/ant/taskdefs/condition/Not.java
new file mode 100644
index 000000000..384d2c81e
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Not.java
@@ -0,0 +1,80 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * &lt;not&gt; condition.
+ *
+ * Evaluates to true if the single condition nested into it is false
+ * and vice versa.
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class Not extends ConditionBase implements Condition {
+
+    public boolean eval() throws BuildException {
+        if (countConditions() > 1) {
+            throw new BuildException("You must not nest more than one condition into <not>");
+        }
+        if (countConditions() < 1) {
+            throw new BuildException("You must nest a condition into <not>");
+        }
+        return !((Condition) getConditions().nextElement()).eval();
+    }
+
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Or.java b/src/main/org/apache/tools/ant/taskdefs/condition/Or.java
new file mode 100644
index 000000000..edfd424ff
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Or.java
@@ -0,0 +1,83 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import java.util.Enumeration;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * &lt;or&gt; condition container.
+ *
+ * <p>Iterates over all conditions and returns true as soon as one
+ * evaluates to true.</p>
+ * 
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class Or extends ConditionBase implements Condition {
+
+    public boolean eval() throws BuildException {
+        Enumeration enum = getConditions();
+        while (enum.hasMoreElements()) {
+            Condition c = (Condition) enum.nextElement();
+            if (c.eval()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Os.java b/src/main/org/apache/tools/ant/taskdefs/condition/Os.java
new file mode 100644
index 000000000..db3e09410
--- /dev/null
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Os.java
@@ -0,0 +1,90 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs.condition;
+
+import org.apache.tools.ant.BuildException;
+
+/**
+ * Condition that tests the OS type.
+ *
+ * @author <a href="mailto:stefan.bodewig@epost.de>Stefan Bodewig</a>
+ * @version $Revision$
+ */
+public class Os implements Condition {
+    private String family;
+
+    public void setFamily(String f) {family = f.toLowerCase();}
+
+    public boolean eval() throws BuildException {
+        String osName = System.getProperty("os.name").toLowerCase();
+        String pathSep = System.getProperty("path.separator");
+        if (family != null) {
+            if (family.equals("windows")) {
+                return osName.indexOf("windows") > -1;
+            } else if (family.equals("dos")) {
+                return pathSep.equals(";");
+            } else if (family.equals("mac")) {
+                return osName.indexOf("mac") > -1;
+            } else if (family.equals("unix")) {
+                return pathSep.equals(":")
+                    && (!osName.startsWith("mac") || osName.endsWith("x"));
+            }
+            throw new BuildException("Don\'t know how to detect os family \""
+                                     + family + "\"");
+        }
+        return false;
+    }
+
+}
diff --git a/src/main/org/apache/tools/ant/taskdefs/defaults.properties b/src/main/org/apache/tools/ant/taskdefs/defaults.properties
index ce50af8da..871e55712 100644
--- a/src/main/org/apache/tools/ant/taskdefs/defaults.properties
+++ b/src/main/org/apache/tools/ant/taskdefs/defaults.properties
@@ -51,6 +51,7 @@ pathconvert=org.apache.tools.ant.taskdefs.PathConvert
 ear=org.apache.tools.ant.taskdefs.Ear
 parallel=org.apache.tools.ant.taskdefs.Parallel
 sequential=org.apache.tools.ant.taskdefs.Sequential
+condition=org.apache.tools.ant.taskdefs.ConditionTask
 
 # optional tasks
 script=org.apache.tools.ant.taskdefs.optional.Script
diff --git a/src/main/org/apache/tools/ant/types/Path.java b/src/main/org/apache/tools/ant/types/Path.java
index 97998e1ad..d8a842b79 100644
--- a/src/main/org/apache/tools/ant/types/Path.java
+++ b/src/main/org/apache/tools/ant/types/Path.java
@@ -138,6 +138,11 @@ public class Path extends DataType implements Cloneable {
         elements = new Vector();
     }
 
+    public void setProject(Project p) {
+        this.project = p;
+    }
+    public Project getProject() {return project;}
+
     /**
      * Adds a element definition to the path.
      * @param location the location of the element to add (must not be
@@ -285,7 +290,11 @@ public class Path extends DataType implements Cloneable {
                     addUnlessPresent(result, parts[j]);
                 }
             } else if (o instanceof Path) {
-                String[] parts = ((Path) o).list();
+                Path p = (Path) o;
+                if (p.getProject() == null) {
+                    p.setProject(project);
+                }
+                String[] parts = p.list();
                 for (int j=0; j<parts.length; j++) {
                     addUnlessPresent(result, parts[j]);
                 }