trunk/src/main/org/apache/tools/ant/taskdefs/Property.java - ant - Git at Google

 /*
  *  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.taskdefs;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.Method;
 import java.net.URL;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Vector;

 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Project;
 import org.apache.tools.ant.PropertyHelper;
 import org.apache.tools.ant.Task;
 import org.apache.tools.ant.types.Path;
 import org.apache.tools.ant.types.Reference;
 import org.apache.tools.ant.util.FileUtils;
 import org.apache.tools.ant.property.ResolvePropertyMap;

 /**
  * Sets a property by name, or set of properties (from file or
  * resource) in the project.  </p>
  * Properties are immutable: whoever sets a property first freezes it for the
  * rest of the build; they are most definitely not variable.
  * <p>There are five ways to set properties:</p>
  * <ul>
  *   <li>By supplying both the <i>name</i> and <i>value</i> attribute.</li>
  *   <li>By supplying both the <i>name</i> and <i>refid</i> attribute.</li>
  *   <li>By setting the <i>file</i> attribute with the filename of the property
  *     file to load. This property file has the format as defined by the file used
  *     in the class java.util.Properties.</li>
  *   <li>By setting the <i>resource</i> attribute with the resource name of the
  *     property file to load. This property file has the format as defined by the
  *     file used in the class java.util.Properties.</li>
  *   <li>By setting the <i>environment</i> attribute with a prefix to use.
  *     Properties will be defined for every environment variable by
  *     prefixing the supplied name and a period to the name of the variable.</li>
  * </ul>
  * <p>Although combinations of these ways are possible, only one should be used
  * at a time. Problems might occur with the order in which properties are set, for
  * instance.</p>
  * <p>The value part of the properties being set, might contain references to other
  * properties. These references are resolved at the time these properties are set.
  * This also holds for properties loaded from a property file.</p>
  * Properties are case sensitive.
  *
  * @since Ant 1.1
  *
  * @ant.attribute.group name="name" description="One of these, when using the name attribute"
  * @ant.attribute.group name="noname" description="One of these, when not using the name attribute"
  * @ant.task category="property"
  */
 public class Property extends Task {

     // CheckStyle:VisibilityModifier OFF - bc
     protected String name;
     protected String value;
     protected File file;
     protected URL url;
     protected String resource;
     protected Path classpath;
     protected String env;
     protected Reference ref;
     protected String prefix;
     private Project fallback;
     private Object untypedValue;

     protected boolean userProperty; // set read-only properties
     // CheckStyle:VisibilityModifier ON

     /**
      * Constructor for Property.
      */
     public Property() {
         this(false);
     }

     /**
      * Constructor for Property.
      * @param userProperty if true this is a user property
      * @since Ant 1.5
      */
     protected Property(boolean userProperty) {
         this(userProperty, null);
     }

     /**
      * Constructor for Property.
      * @param userProperty if true this is a user property
      * @param fallback a project to use to look for references if the reference is
      *                 not in the current project
      * @since Ant 1.5
      */
     protected Property(boolean userProperty, Project fallback) {
         this.userProperty = userProperty;
         this.fallback = fallback;
     }

     /**
      * The name of the property to set.
      * @param name property name
      */
     public void setName(String name) {
         this.name = name;
     }

     /**
      * Get the property name.
      * @return the property name
      */
     public String getName() {
         return name;
     }

     /**
      * Sets the property to the absolute filename of the
      * given file. If the value of this attribute is an absolute path, it
      * is left unchanged (with / and \ characters converted to the
      * current platforms conventions). Otherwise it is taken as a path
      * relative to the project's basedir and expanded.
      * @param location path to set
      *
      * @ant.attribute group="name"
      */
     public void setLocation(File location) {
         setValue(location.getAbsolutePath());
     }

     /* the following method is first in source so IH will pick it up first:
      * Hopefully we'll never get any classes compiled by wise-guy compilers that behave otherwise...
      */

     /**
      * Set the value of the property.
      * @param value the value to use.
      */
     public void setValue(Object value) {
         this.untypedValue = value;
         //preserve protected string value for subclasses :(
         this.value = value == null ? null : value.toString();
     }

     /**
      * Set the value of the property as a String.
      * @param value value to assign
      *
      * @ant.attribute group="name"
      */
     public void setValue(String value) {
         setValue((Object) value);
     }

     /**
      * Get the property value.
      * @return the property value
      */
     public String getValue() {
         return value;
     }

     /**
      * Filename of a property file to load.
      * @param file filename
      *
      * @ant.attribute group="noname"
      */
     public void setFile(File file) {
         this.file = file;
     }

     /**
      * Get the file attribute.
      * @return the file attribute
      */
     public File getFile() {
         return file;
     }

     /**
      * The url from which to load properties.
      * @param url url string
      *
      * @ant.attribute group="noname"
      */
     public void setUrl(URL url) {
         this.url = url;
     }

     /**
      * Get the url attribute.
      * @return the url attribute
      */
     public URL getUrl() {
         return url;
     }

     /**
      * Prefix to apply to properties loaded using <code>file</code>
      * or <code>resource</code>.
      * A "." is appended to the prefix if not specified.
      * @param prefix prefix string
      * @since Ant 1.5
      */
     public void setPrefix(String prefix) {
         this.prefix = prefix;
         if (!prefix.endsWith(".")) {
             this.prefix += ".";
         }
     }

     /**
      * Get the prefix attribute.
      * @return the prefix attribute
      * @since Ant 1.5
      */
     public String getPrefix() {
         return prefix;
     }

     /**
      * Sets a reference to an Ant datatype
      * declared elsewhere.
      * Only yields reasonable results for references
      * PATH like structures or properties.
      * @param ref reference
      *
      * @ant.attribute group="name"
      */
     public void setRefid(Reference ref) {
         this.ref = ref;
     }

     /**
      * Get the refid attribute.
      * @return the refid attribute
      */
     public Reference getRefid() {
         return ref;
     }

     /**
      * The resource name of a property file to load
      * @param resource resource on classpath
      *
      * @ant.attribute group="noname"
      */
     public void setResource(String resource) {
         this.resource = resource;
     }

     /**
      * Get the resource attribute.
      * @return the resource attribute
      */
     public String getResource() {
         return resource;
     }

     /**
      * Prefix to use when retrieving environment variables.
      * Thus if you specify environment=&quot;myenv&quot;
      * you will be able to access OS-specific
      * environment variables via property names &quot;myenv.PATH&quot; or
      * &quot;myenv.TERM&quot;.
      * <p>
      * Note that if you supply a property name with a final
      * &quot;.&quot; it will not be doubled. ie environment=&quot;myenv.&quot; will still
      * allow access of environment variables through &quot;myenv.PATH&quot; and
      * &quot;myenv.TERM&quot;. This functionality is currently only implemented
      * on select platforms. Feel free to send patches to increase the number of platforms
      * this functionality is supported on ;).<br>
      * Note also that properties are case sensitive, even if the
      * environment variables on your operating system are not, e.g. it
      * will be ${env.Path} not ${env.PATH} on Windows 2000.
      * @param env prefix
      *
      * @ant.attribute group="noname"
      */
     public void setEnvironment(String env) {
         this.env = env;
     }

     /**
      * Get the environment attribute.
      * @return the environment attribute
      * @since Ant 1.5
      */
     public String getEnvironment() {
         return env;
     }

     /**
      * The classpath to use when looking up a resource.
      * @param classpath to add to any existing classpath
      */
     public void setClasspath(Path classpath) {
         if (this.classpath == null) {
             this.classpath = classpath;
         } else {
             this.classpath.append(classpath);
         }
     }

     /**
      * The classpath to use when looking up a resource.
      * @return a path to be configured
      */
     public Path createClasspath() {
         if (this.classpath == null) {
             this.classpath = new Path(getProject());
         }
         return this.classpath.createPath();
     }

     /**
      * the classpath to use when looking up a resource,
      * given as reference to a &lt;path&gt; defined elsewhere
      * @param r a reference to a classpath
      */
     public void setClasspathRef(Reference r) {
         createClasspath().setRefid(r);
     }

     /**
      * Get the classpath used when looking up a resource.
      * @return the classpath
      * @since Ant 1.5
      */
     public Path getClasspath() {
         return classpath;
     }

     /**
      * @param userProperty ignored
      * @deprecated since 1.5.x.
      *             This was never a supported feature and has been
      *             deprecated without replacement.
      * @ant.attribute ignore="true"
      */
     public void setUserProperty(boolean userProperty) {
         log("DEPRECATED: Ignoring request to set user property in Property"
             + " task.", Project.MSG_WARN);
     }

     /**
      * get the value of this property
      * @return the current value or the empty string
      */
     public String toString() {
         return value == null ? "" : value;
     }

     /**
      * set the property in the project to the value.
      * if the task was give a file, resource or env attribute
      * here is where it is loaded
      * @throws BuildException on error
      */
     public void execute() throws BuildException {
         if (getProject() == null) {
             throw new IllegalStateException("project has not been set");
         }

         if (name != null) {
             if (untypedValue == null && ref == null) {
                 throw new BuildException("You must specify value, location or "
                                          + "refid with the name attribute",
                                          getLocation());
             }
         } else {
             if (url == null && file == null && resource == null && env == null) {
                 throw new BuildException("You must specify url, file, resource or "
                                          + "environment when not using the "
                                          + "name attribute", getLocation());
             }
         }

         if (url == null && file == null && resource == null && prefix != null) {
             throw new BuildException("Prefix is only valid when loading from "
                                      + "a url, file or resource", getLocation());
         }

         if (name != null && untypedValue != null) {
             addProperty(name, untypedValue);
         }

         if (file != null) {
             loadFile(file);
         }

         if (url != null) {
             loadUrl(url);
         }

         if (resource != null) {
             loadResource(resource);
         }

         if (env != null) {
             loadEnvironment(env);
         }

         if ((name != null) && (ref != null)) {
             try {
                 addProperty(name,
                             ref.getReferencedObject(getProject()).toString());
             } catch (BuildException be) {
                 if (fallback != null) {
                     addProperty(name,
                                 ref.getReferencedObject(fallback).toString());
                 } else {
                     throw be;
                 }
             }
         }
     }

     /**
      * load properties from a url
      * @param url url to load from
      * @throws BuildException on error
      */
     protected void loadUrl(URL url) throws BuildException {
         Properties props = new Properties();
         log("Loading " + url, Project.MSG_VERBOSE);
         try {
             InputStream is = url.openStream();
             try {
                 loadProperties(props, is, url.getFile().endsWith(".xml"));
             } finally {
                 if (is != null) {
                     is.close();
                 }
             }
             addProperties(props);
         } catch (IOException ex) {
             throw new BuildException(ex, getLocation());
         }
     }

     /**
      * Loads the properties defined in the InputStream into the given
      * property. On Java5+ it supports reading from XML based property
      * definition.
      * @param props The property object to load into
      * @param is    The input stream from where to load
      * @param isXml <tt>true</tt> if we should try to load from xml
      * @throws IOException if something goes wrong
      * @since 1.7.1
      * @see http://java.sun.com/dtd/properties.dtd
      * @see java.util.Properties#loadFromXML(InputStream)
      */
     private void loadProperties(
         Properties props, InputStream is, boolean isXml) throws IOException {
         if (isXml) {
             // load the xml based property definition
             // use reflection because of bwc to Java 1.3
             try {
                 Method loadXmlMethod = props.getClass().getMethod("loadFromXML",
                         new Class[] {InputStream.class});
                 loadXmlMethod.invoke(props, new Object[] {is});
             } catch (NoSuchMethodException e) {
                 e.printStackTrace();
                 log("Can not load xml based property definition on Java < 5");
             } catch (Exception e) {
                 // no-op
                 e.printStackTrace();
             }
         } else {
             // load ".properties" format
             props.load(is);
         }
     }

     /**
      * load properties from a file
      * @param file file to load
      * @throws BuildException on error
      */
     protected void loadFile(File file) throws BuildException {
         Properties props = new Properties();
         log("Loading " + file.getAbsolutePath(), Project.MSG_VERBOSE);
         try {
             if (file.exists()) {
                 FileInputStream  fis = null;
                 try {
                     fis = new FileInputStream(file);
                     loadProperties(props, fis, file.getName().endsWith(".xml"));
                 } finally {
                     FileUtils.close(fis);
                 }
                 addProperties(props);
             } else {
                 log("Unable to find property file: " + file.getAbsolutePath(),
                         Project.MSG_VERBOSE);
             }
         } catch (IOException ex) {
             throw new BuildException(ex, getLocation());
         }
     }

     /**
      * load properties from a resource in the current classpath
      * @param name name of resource to load
      */
     protected void loadResource(String name) {
         Properties props = new Properties();
         log("Resource Loading " + name, Project.MSG_VERBOSE);
         InputStream is = null;
         try {
             ClassLoader cL = null;

             if (classpath != null) {
                 cL = getProject().createClassLoader(classpath);
             } else {
                 cL = this.getClass().getClassLoader();
             }

             if (cL == null) {
                 is = ClassLoader.getSystemResourceAsStream(name);
             } else {
                 is = cL.getResourceAsStream(name);
             }

             if (is != null) {
                 loadProperties(props, is, name.endsWith(".xml"));
                 addProperties(props);
             } else {
                 log("Unable to find resource " + name, Project.MSG_WARN);
             }
         } catch (IOException ex) {
             throw new BuildException(ex, getLocation());
         } finally {
             if (is != null) {
                 try {
                     is.close();
                 } catch (IOException e) {
                     // ignore
                 }
             }
         }
     }

     /**
      * load the environment values
      * @param prefix prefix to place before them
      */
     protected void loadEnvironment(String prefix) {
         Properties props = new Properties();
         if (!prefix.endsWith(".")) {
             prefix += ".";
         }
         log("Loading Environment " + prefix, Project.MSG_VERBOSE);
         Vector osEnv = Execute.getProcEnvironment();
         for (Enumeration e = osEnv.elements(); e.hasMoreElements();) {
             String entry = (String) e.nextElement();
             int pos = entry.indexOf('=');
             if (pos == -1) {
                 log("Ignoring: " + entry, Project.MSG_WARN);
             } else {
                 props.put(prefix + entry.substring(0, pos),
                 entry.substring(pos + 1));
             }
         }
         addProperties(props);
     }

     /**
      * iterate through a set of properties,
      * resolve them then assign them
      * @param props the properties to iterate over
      */
     protected void addProperties(Properties props) {
         HashMap m = new HashMap(props);
         resolveAllProperties(m);
         for (Iterator it = m.keySet().iterator(); it.hasNext();) {
             Object k = it.next();
             if (k instanceof String) {
                 String propertyName = (String) k;
                 if (prefix != null) {
                     propertyName = prefix + propertyName;
                 }
                 addProperty(propertyName, m.get(k));
             }
         }
     }

     /**
      * add a name value pair to the project property set
      * @param n name of property
      * @param v value to set
      */
     protected void addProperty(String n, String v) {
         addProperty(n, (Object) v);
     }

     /**
      * add a name value pair to the project property set
      * @param n name of property
      * @param v value to set
      * @since Ant 1.8
      */
     protected void addProperty(String n, Object v) {
         PropertyHelper ph = PropertyHelper.getPropertyHelper(getProject());
         if (userProperty) {
             if (ph.getUserProperty(n) == null) {
                 ph.setInheritedProperty(n, v);
             } else {
                 log("Override ignored for " + n, Project.MSG_VERBOSE);
             }
         } else {
             ph.setNewProperty(n, v);
         }
     }

     /**
      * resolve properties inside a properties hashtable
      * @param props properties object to resolve
      */
     private void resolveAllProperties(Map props) throws BuildException {
         PropertyHelper propertyHelper
             = (PropertyHelper) PropertyHelper.getPropertyHelper(getProject());
         new ResolvePropertyMap(
             getProject(),
             propertyHelper,
             propertyHelper.getExpanders()).resolveAllProperties(props);
     }

 }
	/*
	* 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.taskdefs;

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.lang.reflect.Method;
	import java.net.URL;
	import java.util.Enumeration;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Properties;
	import java.util.Vector;

	import org.apache.tools.ant.BuildException;
	import org.apache.tools.ant.Project;
	import org.apache.tools.ant.PropertyHelper;
	import org.apache.tools.ant.Task;
	import org.apache.tools.ant.types.Path;
	import org.apache.tools.ant.types.Reference;
	import org.apache.tools.ant.util.FileUtils;
	import org.apache.tools.ant.property.ResolvePropertyMap;

	/**
	* Sets a property by name, or set of properties (from file or
	* resource) in the project. </p>
	* Properties are immutable: whoever sets a property first freezes it for the
	* rest of the build; they are most definitely not variable.
	* <p>There are five ways to set properties:</p>
	* <ul>
	* <li>By supplying both the <i>name</i> and <i>value</i> attribute.</li>
	* <li>By supplying both the <i>name</i> and <i>refid</i> attribute.</li>
	* <li>By setting the <i>file</i> attribute with the filename of the property
	* file to load. This property file has the format as defined by the file used
	* in the class java.util.Properties.</li>
	* <li>By setting the <i>resource</i> attribute with the resource name of the
	* property file to load. This property file has the format as defined by the
	* file used in the class java.util.Properties.</li>
	* <li>By setting the <i>environment</i> attribute with a prefix to use.
	* Properties will be defined for every environment variable by
	* prefixing the supplied name and a period to the name of the variable.</li>
	* </ul>
	* <p>Although combinations of these ways are possible, only one should be used
	* at a time. Problems might occur with the order in which properties are set, for
	* instance.</p>
	* <p>The value part of the properties being set, might contain references to other
	* properties. These references are resolved at the time these properties are set.
	* This also holds for properties loaded from a property file.</p>
	* Properties are case sensitive.
	*
	* @since Ant 1.1
	*
	* @ant.attribute.group name="name" description="One of these, when using the name attribute"
	* @ant.attribute.group name="noname" description="One of these, when not using the name attribute"
	* @ant.task category="property"
	*/
	public class Property extends Task {

	// CheckStyle:VisibilityModifier OFF - bc
	protected String name;
	protected String value;
	protected File file;
	protected URL url;
	protected String resource;
	protected Path classpath;
	protected String env;
	protected Reference ref;
	protected String prefix;
	private Project fallback;
	private Object untypedValue;

	protected boolean userProperty; // set read-only properties
	// CheckStyle:VisibilityModifier ON

	/**
	* Constructor for Property.
	*/
	public Property() {
	this(false);
	}

	/**
	* Constructor for Property.
	* @param userProperty if true this is a user property
	* @since Ant 1.5
	*/
	protected Property(boolean userProperty) {
	this(userProperty, null);
	}

	/**
	* Constructor for Property.
	* @param userProperty if true this is a user property
	* @param fallback a project to use to look for references if the reference is
	* not in the current project
	* @since Ant 1.5
	*/
	protected Property(boolean userProperty, Project fallback) {
	this.userProperty = userProperty;
	this.fallback = fallback;
	}

	/**
	* The name of the property to set.
	* @param name property name
	*/
	public void setName(String name) {
	this.name = name;
	}

	/**
	* Get the property name.
	* @return the property name
	*/
	public String getName() {
	return name;
	}

	/**
	* Sets the property to the absolute filename of the
	* given file. If the value of this attribute is an absolute path, it
	* is left unchanged (with / and \ characters converted to the
	* current platforms conventions). Otherwise it is taken as a path
	* relative to the project's basedir and expanded.
	* @param location path to set
	*
	* @ant.attribute group="name"
	*/
	public void setLocation(File location) {
	setValue(location.getAbsolutePath());
	}

	/* the following method is first in source so IH will pick it up first:
	* Hopefully we'll never get any classes compiled by wise-guy compilers that behave otherwise...
	*/

	/**
	* Set the value of the property.
	* @param value the value to use.
	*/
	public void setValue(Object value) {
	this.untypedValue = value;
	//preserve protected string value for subclasses :(
	this.value = value == null ? null : value.toString();
	}

	/**
	* Set the value of the property as a String.
	* @param value value to assign
	*
	* @ant.attribute group="name"
	*/
	public void setValue(String value) {
	setValue((Object) value);
	}

	/**
	* Get the property value.
	* @return the property value
	*/
	public String getValue() {
	return value;
	}

	/**
	* Filename of a property file to load.
	* @param file filename
	*
	* @ant.attribute group="noname"
	*/
	public void setFile(File file) {
	this.file = file;
	}

	/**
	* Get the file attribute.
	* @return the file attribute
	*/
	public File getFile() {
	return file;
	}

	/**
	* The url from which to load properties.
	* @param url url string
	*
	* @ant.attribute group="noname"
	*/
	public void setUrl(URL url) {
	this.url = url;
	}

	/**
	* Get the url attribute.
	* @return the url attribute
	*/
	public URL getUrl() {
	return url;
	}

	/**
	* Prefix to apply to properties loaded using <code>file</code>
	* or <code>resource</code>.
	* A "." is appended to the prefix if not specified.
	* @param prefix prefix string
	* @since Ant 1.5
	*/
	public void setPrefix(String prefix) {
	this.prefix = prefix;
	if (!prefix.endsWith(".")) {
	this.prefix += ".";
	}
	}

	/**
	* Get the prefix attribute.
	* @return the prefix attribute
	* @since Ant 1.5
	*/
	public String getPrefix() {
	return prefix;
	}

	/**
	* Sets a reference to an Ant datatype
	* declared elsewhere.
	* Only yields reasonable results for references
	* PATH like structures or properties.
	* @param ref reference
	*
	* @ant.attribute group="name"
	*/
	public void setRefid(Reference ref) {
	this.ref = ref;
	}

	/**
	* Get the refid attribute.
	* @return the refid attribute
	*/
	public Reference getRefid() {
	return ref;
	}

	/**
	* The resource name of a property file to load
	* @param resource resource on classpath
	*
	* @ant.attribute group="noname"
	*/
	public void setResource(String resource) {
	this.resource = resource;
	}

	/**
	* Get the resource attribute.
	* @return the resource attribute
	*/
	public String getResource() {
	return resource;
	}

	/**
	* Prefix to use when retrieving environment variables.
	* Thus if you specify environment="myenv"
	* you will be able to access OS-specific
	* environment variables via property names "myenv.PATH" or
	* "myenv.TERM".
	* <p>
	* Note that if you supply a property name with a final
	* "." it will not be doubled. ie environment="myenv." will still
	* allow access of environment variables through "myenv.PATH" and
	* "myenv.TERM". This functionality is currently only implemented
	* on select platforms. Feel free to send patches to increase the number of platforms
	* this functionality is supported on ;).<br>
	* Note also that properties are case sensitive, even if the
	* environment variables on your operating system are not, e.g. it
	* will be ${env.Path} not ${env.PATH} on Windows 2000.
	* @param env prefix
	*
	* @ant.attribute group="noname"
	*/
	public void setEnvironment(String env) {
	this.env = env;
	}

	/**
	* Get the environment attribute.
	* @return the environment attribute
	* @since Ant 1.5
	*/
	public String getEnvironment() {
	return env;
	}

	/**
	* The classpath to use when looking up a resource.
	* @param classpath to add to any existing classpath
	*/
	public void setClasspath(Path classpath) {
	if (this.classpath == null) {
	this.classpath = classpath;
	} else {
	this.classpath.append(classpath);
	}
	}

	/**
	* The classpath to use when looking up a resource.
	* @return a path to be configured
	*/
	public Path createClasspath() {
	if (this.classpath == null) {
	this.classpath = new Path(getProject());
	}
	return this.classpath.createPath();
	}

	/**
	* the classpath to use when looking up a resource,
	* given as reference to a <path> defined elsewhere
	* @param r a reference to a classpath
	*/
	public void setClasspathRef(Reference r) {
	createClasspath().setRefid(r);
	}

	/**
	* Get the classpath used when looking up a resource.
	* @return the classpath
	* @since Ant 1.5
	*/
	public Path getClasspath() {
	return classpath;
	}

	/**
	* @param userProperty ignored
	* @deprecated since 1.5.x.
	* This was never a supported feature and has been
	* deprecated without replacement.
	* @ant.attribute ignore="true"
	*/
	public void setUserProperty(boolean userProperty) {
	log("DEPRECATED: Ignoring request to set user property in Property"
	+ " task.", Project.MSG_WARN);
	}

	/**
	* get the value of this property
	* @return the current value or the empty string
	*/
	public String toString() {
	return value == null ? "" : value;
	}

	/**
	* set the property in the project to the value.
	* if the task was give a file, resource or env attribute
	* here is where it is loaded
	* @throws BuildException on error
	*/
	public void execute() throws BuildException {
	if (getProject() == null) {
	throw new IllegalStateException("project has not been set");
	}

	if (name != null) {
	if (untypedValue == null && ref == null) {
	throw new BuildException("You must specify value, location or "
	+ "refid with the name attribute",
	getLocation());
	}
	} else {
	if (url == null && file == null && resource == null && env == null) {
	throw new BuildException("You must specify url, file, resource or "
	+ "environment when not using the "
	+ "name attribute", getLocation());
	}
	}

	if (url == null && file == null && resource == null && prefix != null) {
	throw new BuildException("Prefix is only valid when loading from "
	+ "a url, file or resource", getLocation());
	}

	if (name != null && untypedValue != null) {
	addProperty(name, untypedValue);
	}

	if (file != null) {
	loadFile(file);
	}

	if (url != null) {
	loadUrl(url);
	}

	if (resource != null) {
	loadResource(resource);
	}

	if (env != null) {
	loadEnvironment(env);
	}

	if ((name != null) && (ref != null)) {
	try {
	addProperty(name,
	ref.getReferencedObject(getProject()).toString());
	} catch (BuildException be) {
	if (fallback != null) {
	addProperty(name,
	ref.getReferencedObject(fallback).toString());
	} else {
	throw be;
	}
	}
	}
	}

	/**
	* load properties from a url
	* @param url url to load from
	* @throws BuildException on error
	*/
	protected void loadUrl(URL url) throws BuildException {
	Properties props = new Properties();
	log("Loading " + url, Project.MSG_VERBOSE);
	try {
	InputStream is = url.openStream();
	try {
	loadProperties(props, is, url.getFile().endsWith(".xml"));
	} finally {
	if (is != null) {
	is.close();
	}
	}
	addProperties(props);
	} catch (IOException ex) {
	throw new BuildException(ex, getLocation());
	}
	}

	/**
	* Loads the properties defined in the InputStream into the given
	* property. On Java5+ it supports reading from XML based property
	* definition.
	* @param props The property object to load into
	* @param is The input stream from where to load
	* @param isXml <tt>true</tt> if we should try to load from xml
	* @throws IOException if something goes wrong
	* @since 1.7.1
	* @see http://java.sun.com/dtd/properties.dtd
	* @see java.util.Properties#loadFromXML(InputStream)
	*/
	private void loadProperties(
	Properties props, InputStream is, boolean isXml) throws IOException {
	if (isXml) {
	// load the xml based property definition
	// use reflection because of bwc to Java 1.3
	try {
	Method loadXmlMethod = props.getClass().getMethod("loadFromXML",
	new Class[] {InputStream.class});
	loadXmlMethod.invoke(props, new Object[] {is});
	} catch (NoSuchMethodException e) {
	e.printStackTrace();
	log("Can not load xml based property definition on Java < 5");
	} catch (Exception e) {
	// no-op
	e.printStackTrace();
	}
	} else {
	// load ".properties" format
	props.load(is);
	}
	}

	/**
	* load properties from a file
	* @param file file to load
	* @throws BuildException on error
	*/
	protected void loadFile(File file) throws BuildException {
	Properties props = new Properties();
	log("Loading " + file.getAbsolutePath(), Project.MSG_VERBOSE);
	try {
	if (file.exists()) {
	FileInputStream fis = null;
	try {
	fis = new FileInputStream(file);
	loadProperties(props, fis, file.getName().endsWith(".xml"));
	} finally {
	FileUtils.close(fis);
	}
	addProperties(props);
	} else {
	log("Unable to find property file: " + file.getAbsolutePath(),
	Project.MSG_VERBOSE);
	}
	} catch (IOException ex) {
	throw new BuildException(ex, getLocation());
	}
	}

	/**
	* load properties from a resource in the current classpath
	* @param name name of resource to load
	*/
	protected void loadResource(String name) {
	Properties props = new Properties();
	log("Resource Loading " + name, Project.MSG_VERBOSE);
	InputStream is = null;
	try {
	ClassLoader cL = null;

	if (classpath != null) {
	cL = getProject().createClassLoader(classpath);
	} else {
	cL = this.getClass().getClassLoader();
	}

	if (cL == null) {
	is = ClassLoader.getSystemResourceAsStream(name);
	} else {
	is = cL.getResourceAsStream(name);
	}

	if (is != null) {
	loadProperties(props, is, name.endsWith(".xml"));
	addProperties(props);
	} else {
	log("Unable to find resource " + name, Project.MSG_WARN);
	}
	} catch (IOException ex) {
	throw new BuildException(ex, getLocation());
	} finally {
	if (is != null) {
	try {
	is.close();
	} catch (IOException e) {
	// ignore
	}
	}
	}
	}

	/**
	* load the environment values
	* @param prefix prefix to place before them
	*/
	protected void loadEnvironment(String prefix) {
	Properties props = new Properties();
	if (!prefix.endsWith(".")) {
	prefix += ".";
	}
	log("Loading Environment " + prefix, Project.MSG_VERBOSE);
	Vector osEnv = Execute.getProcEnvironment();
	for (Enumeration e = osEnv.elements(); e.hasMoreElements();) {
	String entry = (String) e.nextElement();
	int pos = entry.indexOf('=');
	if (pos == -1) {
	log("Ignoring: " + entry, Project.MSG_WARN);
	} else {
	props.put(prefix + entry.substring(0, pos),
	entry.substring(pos + 1));
	}
	}
	addProperties(props);
	}

	/**
	* iterate through a set of properties,
	* resolve them then assign them
	* @param props the properties to iterate over
	*/
	protected void addProperties(Properties props) {
	HashMap m = new HashMap(props);
	resolveAllProperties(m);
	for (Iterator it = m.keySet().iterator(); it.hasNext();) {
	Object k = it.next();
	if (k instanceof String) {
	String propertyName = (String) k;
	if (prefix != null) {
	propertyName = prefix + propertyName;
	}
	addProperty(propertyName, m.get(k));
	}
	}
	}

	/**
	* add a name value pair to the project property set
	* @param n name of property
	* @param v value to set
	*/
	protected void addProperty(String n, String v) {
	addProperty(n, (Object) v);
	}

	/**
	* add a name value pair to the project property set
	* @param n name of property
	* @param v value to set
	* @since Ant 1.8
	*/
	protected void addProperty(String n, Object v) {
	PropertyHelper ph = PropertyHelper.getPropertyHelper(getProject());
	if (userProperty) {
	if (ph.getUserProperty(n) == null) {
	ph.setInheritedProperty(n, v);
	} else {
	log("Override ignored for " + n, Project.MSG_VERBOSE);
	}
	} else {
	ph.setNewProperty(n, v);
	}
	}

	/**
	* resolve properties inside a properties hashtable
	* @param props properties object to resolve
	*/
	private void resolveAllProperties(Map props) throws BuildException {
	PropertyHelper propertyHelper
	= (PropertyHelper) PropertyHelper.getPropertyHelper(getProject());
	new ResolvePropertyMap(
	getProject(),
	propertyHelper,
	propertyHelper.getExpanders()).resolveAllProperties(props);
	}

	}