mirror of https://github.com/pf4j/pf4j.git
Andreas Rudolph
6 years ago
committed by
Decebal Suiu
10 changed files with 395 additions and 4 deletions
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/* |
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* Copyright (C) 2012-present the original author or authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package org.pf4j.asm; |
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import org.objectweb.asm.ClassReader; |
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import org.pf4j.Extension; |
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import org.slf4j.Logger; |
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import org.slf4j.LoggerFactory; |
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import java.io.IOException; |
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import java.io.InputStream; |
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import java.util.ArrayList; |
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import java.util.Collections; |
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import java.util.List; |
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/** |
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* This class holds the parameters of an {@link org.pf4j.Extension} |
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* annotation defined for a certain class. |
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* |
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* @author Andreas Rudolph |
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* @author Decebal Suiu |
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*/ |
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public final class ExtensionInfo { |
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private static final Logger log = LoggerFactory.getLogger(ExtensionInfo.class); |
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private final String className; |
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int ordinal = 0; |
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List<String> plugins = new ArrayList<>(); |
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List<String> points = new ArrayList<>(); |
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private ExtensionInfo(String className) { |
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super(); |
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this.className = className; |
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} |
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/** |
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* Get the name of the class, for which extension info was created. |
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* |
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* @return absolute class name |
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*/ |
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public String getClassName() { |
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return className; |
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} |
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/** |
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* Get the {@link Extension#ordinal()} value, that was assigned to the extension. |
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* |
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* @return ordinal value |
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*/ |
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public int getOrdinal() { |
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return ordinal; |
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} |
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/** |
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* Get the {@link Extension#plugins()} value, that was assigned to the extension. |
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* |
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* @return ordinal value |
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*/ |
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public List<String> getPlugins() { |
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return Collections.unmodifiableList(plugins); |
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} |
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/** |
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* Get the {@link Extension#points()} value, that was assigned to the extension. |
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* |
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* @return ordinal value |
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*/ |
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public List<String> getPoints() { |
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return Collections.unmodifiableList(points); |
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} |
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/** |
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* Load an {@link ExtensionInfo} for a certain class. |
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* |
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* @param className absolute class name |
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* @param classLoader class loader to access the class
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* @return the {@link ExtensionInfo}, if the class was annotated with an {@link Extension}, otherwise null |
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*/ |
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public static ExtensionInfo load(String className, ClassLoader classLoader) { |
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try (InputStream input = classLoader.getResourceAsStream(className.replace('.', '/') + ".class")) { |
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ExtensionInfo info = new ExtensionInfo(className); |
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new ClassReader(input).accept(new ExtensionVisitor(info), ClassReader.SKIP_DEBUG); |
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return info; |
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} catch (IOException e) { |
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log.error(e.getMessage(), e); |
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return null; |
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} |
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} |
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} |
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@ -0,0 +1,96 @@
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/* |
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* Copyright (C) 2012-present the original author or authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package org.pf4j.asm; |
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import org.objectweb.asm.AnnotationVisitor; |
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import org.objectweb.asm.ClassVisitor; |
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import org.objectweb.asm.Opcodes; |
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import org.objectweb.asm.Type; |
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import org.pf4j.Extension; |
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import java.util.Arrays; |
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/** |
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* This visitor extracts an {@link ExtensionInfo} from any class, |
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* that holds an {@link Extension} annotation. |
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* <p> |
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* The annotation parameters are extracted from byte code by using the |
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* <a href="https://asm.ow2.io/">ASM library</a>. This makes it possible to |
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* access the {@link Extension} parameters without loading the class into |
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* the class loader. This avoids possible {@link NoClassDefFoundError}'s |
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* for extensions, that can't be loaded due to missing dependencies. |
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* |
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* @author Andreas Rudolph |
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* @author Decebal Suiu |
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*/ |
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class ExtensionVisitor extends ClassVisitor { |
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//private static final Logger log = LoggerFactory.getLogger(ExtensionVisitor.class);
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private static final int ASM_VERSION = Opcodes.ASM7; |
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private final ExtensionInfo extensionInfo; |
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ExtensionVisitor(ExtensionInfo extensionInfo) { |
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super(ASM_VERSION); |
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this.extensionInfo = extensionInfo; |
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} |
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@Override |
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public AnnotationVisitor visitAnnotation(String descriptor, boolean visible) { |
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//if (!descriptor.equals("Lorg/pf4j/Extension;")) {
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if (!Type.getType(descriptor).getClassName().equals(Extension.class.getName())) { |
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return super.visitAnnotation(descriptor, visible); |
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} |
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return new AnnotationVisitor(ASM_VERSION) { |
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@Override |
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public AnnotationVisitor visitArray(final String name) { |
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if ("ordinal".equals(name) || "plugins".equals(name) || "points".equals(name)) { |
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return new AnnotationVisitor(ASM_VERSION, super.visitArray(name)) { |
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@Override |
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public void visit(String key, Object value) { |
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//log.debug("Load annotation attribute {} = {} ({})", name, value, value.getClass().getName());
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if ("ordinal".equals(name)) { |
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extensionInfo.ordinal = Integer.parseInt(value.toString()); |
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} else if ("plugins".equals(name)) { |
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if (value instanceof String) { |
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//log.debug("found plugin " + value);
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extensionInfo.plugins.add((String) value); |
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} else if (value instanceof String[]) { |
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//log.debug("found plugins " + Arrays.toString((String[]) value));
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extensionInfo.plugins.addAll(Arrays.asList((String[]) value)); |
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} else { |
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//log.debug("found plugin " + value.toString());
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extensionInfo.plugins.add(value.toString()); |
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} |
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} else if ("points".equals(name)) { |
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String pointClassName = ((Type) value).getClassName(); |
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//log.debug("found point " + pointClassName);
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extensionInfo.points.add(pointClassName); |
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} |
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super.visit(key, value); |
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} |
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}; |
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} |
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return super.visitArray(name); |
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} |
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}; |
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} |
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} |
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