Split <available> condition into <class-available> and <resource-available>.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271892 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/antlib/core/AbstractAvailableCondition.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.antlib.core;
+
+import org.apache.myrmidon.framework.conditions.Condition;
+import org.apache.myrmidon.api.TaskException;
+import org.apache.tools.todo.types.Path;
+import org.apache.tools.todo.types.PathUtil;
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * An abstract condition which checks for the availability of a particular
+ * resource in a classpath.
+ *
+ * @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a>
+ * @version $Revision$ $Date$
+ */
+public abstract class AbstractAvailableCondition
+    implements Condition
+{
+    private Path m_classpath = new Path();
+
+    /**
+     * Adds a classpath element.
+     */
+    public void addClasspath( final Path classpath )
+        throws TaskException
+    {
+        m_classpath.addPath( classpath );
+    }
+
+    /**
+     * Builds the ClassLoader to use to check resources.
+     */
+    protected ClassLoader buildClassLoader() throws TaskException
+    {
+        final URL[] urls = PathUtil.toURLs( m_classpath );
+        final ClassLoader classLoader;
+        if( urls.length > 0 )
+        {
+            classLoader = new URLClassLoader( urls );
+        }
+        else
+        {
+            // TODO - using system classloader is kinda useless now, because
+            // the system classpath contains almost nothing.  Should be using
+            // the 'common' classloader instead
+            classLoader = ClassLoader.getSystemClassLoader();
+        }
+        return classLoader;
+    }
+}

proposal/myrmidon/src/java/org/apache/antlib/core/Available.java

@@ -1,136 +0,0 @@
-/*
- * Copyright (C) The Apache Software Foundation. All rights reserved.
- *
- * This software is published under the terms of the Apache Software License
- * version 1.1, a copy of which has been included with this distribution in
- * the LICENSE.txt file.
- */
-package org.apache.antlib.core;
-
-import java.net.URL;
-import java.net.URLClassLoader;
-import org.apache.myrmidon.api.TaskContext;
-import org.apache.myrmidon.api.TaskException;
-import org.apache.myrmidon.framework.conditions.Condition;
-import org.apache.tools.todo.types.Path;
-import org.apache.tools.todo.types.PathUtil;
-
-/**
- * A condition that evaluates to true if the requested class or resource
- * is available at runtime.
- *
- * @author Stefano Mazzocchi <a href="mailto:stefano@apache.org">
- *      stefano@apache.org</a>
- * @author <a href="mailto:umagesh@apache.org">Magesh Umasankar</a>
- *
- * @ant:type type="condition" name="available"
- */
-public class Available
-    implements Condition
-{
-    private String m_classname;
-    private Path m_classpath;
-    private ClassLoader m_classLoader;
-    private String m_resource;
-
-    /**
-     * Sets the name of the class to search for.
-     */
-    public void setClassname( final String classname )
-    {
-        if( !"".equals( classname ) )
-        {
-            m_classname = classname;
-        }
-    }
-
-    /**
-     * Adds a classpath element.
-     */
-    public void addClasspath( final Path classpath )
-        throws TaskException
-    {
-        if( m_classpath == null )
-        {
-            m_classpath = classpath;
-        }
-        else
-        {
-            m_classpath.addPath( classpath );
-        }
-    }
-
-    /**
-     * Sets the name of the resource to look for.
-     */
-    public void setResource( final String resource )
-    {
-        m_resource = resource;
-    }
-
-    /**
-     * Evaluates the condition.
-     */
-    public boolean evaluate( final TaskContext context )
-        throws TaskException
-    {
-        if( m_classname == null && m_resource == null )
-        {
-            throw new TaskException( "At least one of (classname|file|resource) is required" );
-        }
-
-        if( m_classpath != null )
-        {
-            final URL[] urls = PathUtil.toURLs( m_classpath );
-            m_classLoader = new URLClassLoader( urls );
-        }
-
-        if( ( m_classname != null ) && !checkClass( m_classname ) )
-        {
-            return false;
-        }
-
-        if( ( m_resource != null ) && !checkResource( m_resource ) )
-        {
-            return false;
-        }
-
-        return true;
-    }
-
-    private boolean checkClass( String classname )
-    {
-        try
-        {
-            final ClassLoader classLoader = getClassLoader();
-            classLoader.loadClass( classname );
-            return true;
-        }
-        catch( ClassNotFoundException e )
-        {
-            return false;
-        }
-        catch( NoClassDefFoundError e )
-        {
-            return false;
-        }
-    }
-
-    private boolean checkResource( String resource )
-    {
-        final ClassLoader classLoader = getClassLoader();
-        return ( null != classLoader.getResourceAsStream( resource ) );
-    }
-
-    private ClassLoader getClassLoader()
-    {
-        if( null == m_classLoader )
-        {
-            return ClassLoader.getSystemClassLoader();
-        }
-        else
-        {
-            return m_classLoader;
-        }
-    }
-}

proposal/myrmidon/src/java/org/apache/antlib/core/ClassAvailableCondition.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.antlib.core;
+
+import org.apache.myrmidon.api.TaskContext;
+import org.apache.myrmidon.api.TaskException;
+import org.apache.myrmidon.framework.conditions.Condition;
+
+/**
+ * A condition that evaluates to true if the requested class is available
+ * at runtime.
+ *
+ * @author Stefano Mazzocchi <a href="mailto:stefano@apache.org">
+ *      stefano@apache.org</a>
+ * @author <a href="mailto:umagesh@apache.org">Magesh Umasankar</a>
+ *
+ * @ant:type type="condition" name="class-available"
+ */
+public class ClassAvailableCondition
+    extends AbstractAvailableCondition
+    implements Condition
+{
+    private String m_classname;
+
+    /**
+     * Sets the name of the class to search for.
+     */
+    public void setClassname( final String classname )
+    {
+        m_classname = classname;
+    }
+
+    /**
+     * Evaluates the condition.
+     */
+    public boolean evaluate( final TaskContext context )
+        throws TaskException
+    {
+        if( m_classname == null )
+        {
+            throw new TaskException( "Classname not specified." );
+        }
+
+        // Build the classloader to use to check resources
+        final ClassLoader classLoader = buildClassLoader();
+
+        // Do the check
+        try
+        {
+            classLoader.loadClass( m_classname );
+            return true;
+        }
+        catch( final Exception e )
+        {
+            return false;
+        }
+    }
+
+}

proposal/myrmidon/src/java/org/apache/antlib/core/ResourceAvailableCondition.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.antlib.core;
+
+import java.io.InputStream;
+import org.apache.avalon.excalibur.io.IOUtil;
+import org.apache.myrmidon.api.TaskContext;
+import org.apache.myrmidon.api.TaskException;
+import org.apache.myrmidon.framework.conditions.Condition;
+
+/**
+ * A condition that evaluates to true if the requested resource is available
+ * at runtime.
+ *
+ * @author Stefano Mazzocchi <a href="mailto:stefano@apache.org">
+ *      stefano@apache.org</a>
+ * @author <a href="mailto:umagesh@apache.org">Magesh Umasankar</a>
+ *
+ * @ant:type type="condition" name="resource-available"
+ */
+public class ResourceAvailableCondition
+    extends AbstractAvailableCondition
+    implements Condition
+{
+    private String m_resource;
+
+    /**
+     * Sets the name of the resource to look for.
+     */
+    public void setResource( final String resource )
+    {
+        m_resource = resource;
+    }
+
+    /**
+     * Evaluates the condition.
+     */
+    public boolean evaluate( final TaskContext context )
+        throws TaskException
+    {
+        if( m_resource == null )
+        {
+            throw new TaskException( "Resource was not specified." );
+        }
+
+        // Check whether the resource is available
+        final ClassLoader classLoader = buildClassLoader();
+        final InputStream instr = classLoader.getResourceAsStream( m_resource );
+        if( instr != null )
+        {
+            IOUtil.shutdownStream( instr );
+            return true;
+        }
+        return false;
+    }
+}