a helper and creator class for script runners

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@481968 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/util/ScriptRunnerCreator.java

@@ -0,0 +1,139 @@
+/*
+ *  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.util;
+
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.Project;
+
+/**
+ * This is a helper class used by ScriptRunnerHelper to
+ * create a ScriptRunner based on a classloader and
+ * on a language.
+ */
+public class ScriptRunnerCreator {
+    private static final String AUTO = "auto";
+    private static final String OATAU = "org.apache.tools.ant.util";
+    private static final String UTIL_OPT = OATAU + ".optional";
+
+    private static final String BSF = "bsf";
+    private static final String BSF_PACK = "org.apache.bsf";
+    private static final String BSF_MANAGER = BSF_PACK + ".BSFManager";
+    private static final String BSF_RUNNER = UTIL_OPT + ".ScriptRunner";
+
+    private static final String JAVAX = "javax";
+    private static final String JAVAX_MANAGER = "javax.script.ScriptEngineManager";
+    private static final String JAVAX_RUNNER = UTIL_OPT + ".JavaxScriptRunner";
+
+    private Project     project;
+    private String      manager;
+    private String      language;
+    private ClassLoader scriptLoader = null;
+
+    /**
+     * Constructor for creator.
+     * @param project the current project.
+     */
+    public ScriptRunnerCreator(Project project) {
+        this.project = project;
+    }
+
+    /**
+     * Create a ScriptRunner.
+     * @param manager      the script manager ("auto" | "bsf" | "javax")
+     * @param language     the language.
+     * @param classLoader  the classloader to use
+     * @return the created script runner.
+     * @throws BuildException if unable to create the ScriptRunner.
+     */
+    public ScriptRunnerBase createRunner(
+        String manager, String language, ClassLoader classLoader) {
+        this.manager      = manager;
+        this.language     = language;
+        this.scriptLoader = classLoader;
+
+        if (language == null) {
+            throw new BuildException("script language must be specified");
+        }
+        if (!manager.equals(AUTO) && !manager.equals(JAVAX) && !manager.equals(BSF)) {
+                throw new BuildException(
+                    "Unsupported language prefix " + manager);
+        }
+
+        // Check for bsf first then javax
+        // This version does not check if the scriptManager
+        // supports the language.
+
+        ScriptRunnerBase ret = null;
+        ret = createRunner(BSF, BSF_MANAGER, BSF_RUNNER);
+        if (ret == null) {
+            ret = createRunner(JAVAX, JAVAX_MANAGER, JAVAX_RUNNER);
+        }
+        if (ret != null) {
+            return ret;
+        }
+        if (JAVAX.equals(manager)) {
+            throw new BuildException(
+                "Unable to load the script engine manager "
+                + "(" + JAVAX_MANAGER + ")");
+        } else if (BSF.equals(manager)) {
+            throw new BuildException(
+                "Unable to load the BSF script engine manager "
+                + "(" + BSF_MANAGER + ")");
+        } else {
+            throw new BuildException(
+                "Unable to load a script engine manager "
+                + "(" + BSF_MANAGER + " or " + JAVAX_MANAGER + ")");
+        }
+    }
+
+    /**
+     * Create a script runner if the scriptManager matches the passed
+     * in manager.
+     * This checks if the script manager exists in the scriptLoader
+     * classloader and if so it creates and returns the script runner.
+     * @param checkManager check if the manager matchs this value.
+     * @param mangagerClass the name of the script manager class.
+     * @param runnerClass   the name of ant's script runner for this manager.
+     * @return the script runner class.
+     * @throws BuildException if there is a problem creating the runner class.
+     */
+    private ScriptRunnerBase createRunner(
+        String checkManager, String managerClass, String runnerClass) {
+        ScriptRunnerBase runner = null;
+        if (!manager.equals(AUTO) && !manager.equals(checkManager)) {
+            return null;
+        }
+        if (scriptLoader.getResource(
+                LoaderUtils.classNameToResource(managerClass)) == null) {
+            return null;
+        }
+        try {
+            runner = (ScriptRunnerBase) Class.forName(
+                runnerClass, true, scriptLoader).newInstance();
+            runner.setProject(project);
+            return runner;
+        } catch (Exception ex) {
+            ReflectUtil.throwBuildException(ex);
+            // NotReached
+        }
+
+        runner.setLanguage(language);
+        runner.setScriptClassLoader(scriptLoader);
+        return runner;
+    }
+}

src/main/org/apache/tools/ant/util/ScriptRunnerHelper.java

@@ -0,0 +1,191 @@
+/*
+ *  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.util;
+
+import org.apache.tools.ant.ProjectComponent;
+import org.apache.tools.ant.types.Path;
+import java.io.File;
+import org.apache.tools.ant.types.Reference;
+
+
+/**
+ * A class to help in creating, setting and getting
+ * script runners.
+ */
+public class ScriptRunnerHelper {
+    private ClasspathUtils.Delegate cpDelegate = null;
+    private File    srcFile;
+    private String  manager = "auto";
+    private String  language;
+    private String  text;
+    private boolean setBeans = true;
+    private ProjectComponent projectComponent;
+    private ClassLoader scriptLoader = null;
+
+    /**
+     * Set the project component associated with this helper.
+     * @param component the project component that owns this helper.
+     */
+    public void setProjectComponent(ProjectComponent component) {
+        this.projectComponent = component;
+    }
+
+    /**
+     * Create and set text on a script.
+     * @return the created or reused script runner.
+     */
+    public ScriptRunnerBase getScriptRunner() {
+        ScriptRunnerBase runner = getRunner();
+        if (srcFile != null) {
+            runner.setSrc(srcFile);
+        }
+        if (text != null) {
+            runner.addText(text);
+        }
+        if (setBeans) {
+            runner.bindToComponent(projectComponent);
+        } else {
+            runner.bindToComponentMinimum(projectComponent);
+        }
+        return runner;
+    }
+
+    /**
+     * Classpath to be used when searching for classes and resources.
+     *
+     * @return an empty Path instance to be configured by Ant.
+     */
+    public Path createClasspath() {
+        return getClassPathDelegate().createClasspath();
+    }
+
+    /**
+     * Set the classpath to be used when searching for classes and resources.
+     *
+     * @param classpath an Ant Path object containing the search path.
+     */
+    public void setClasspath(Path classpath) {
+        getClassPathDelegate().setClasspath(classpath);
+    }
+
+    /**
+     * Set the classpath by reference.
+     *
+     * @param r a Reference to a Path instance to be used as the classpath
+     *          value.
+     */
+    public void setClasspathRef(Reference r) {
+        getClassPathDelegate().setClasspathref(r);
+    }
+
+    /**
+     * Load the script from an external file ; optional.
+     *
+     * @param file the file containing the script source.
+     */
+    public void setSrc(File file) {
+        this.srcFile = file;
+    }
+
+    /**
+     * The script text.
+     *
+     * @param text a component of the script text to be added.
+     */
+    public void addText(String text) {
+        this.text = text;
+    }
+
+    /**
+     * Defines the script manager - defaults to "auto".
+     *
+     * @param manager the scripting manager - "bsf" or "javax" or "auto"
+     */
+    public void setManager(String manager) {
+        this.manager = manager;
+    }
+
+    /**
+     * Defines the language (required).
+     *
+     * @param language the scripting language name for the script.
+     */
+    public void setLanguage(String language) {
+        this.language = language;
+    }
+
+    /**
+     * Get the language.
+     * @return the scripting language.
+     */
+    public String getLanguage() {
+        return language;
+    }
+
+    /**
+     * Set the setbeans attribute.
+     * If this is true, <script> will create variables in the
+     * script instance for all
+     * properties, targets and references of the current project.
+     * It this is false, only the project and self variables will
+     * be set.
+     * The default is true.
+     * @param setBeans the value to set.
+     */
+    public void setSetBeans(boolean setBeans) {
+        this.setBeans = setBeans;
+    }
+
+    /**
+     * Used when called by scriptdef.
+     * @param loader the loader used by scriptdef.
+     */
+    public void setClassLoader(ClassLoader loader) {
+        scriptLoader = loader;
+    }
+
+
+    private ClassLoader generateClassLoader() {
+        if (scriptLoader != null) {
+            return scriptLoader;
+        }
+        if (cpDelegate == null) {
+            scriptLoader = getClass().getClassLoader();
+            return scriptLoader;
+        }
+
+        scriptLoader = cpDelegate.getClassLoader();
+        return scriptLoader;
+    }
+
+    private ClasspathUtils.Delegate getClassPathDelegate() {
+        if (cpDelegate == null) {
+            cpDelegate = ClasspathUtils.getDelegate(projectComponent);
+        }
+        return cpDelegate;
+    }
+
+    /**
+     * Get a script runner.
+     */
+    private ScriptRunnerBase getRunner() {
+        return new ScriptRunnerCreator(
+            projectComponent.getProject()).createRunner(
+                manager, language, generateClassLoader());
+    }
+}