com.google.gwt.dev.javac.asm.CollectAnnotationData.java Source code

Introduction

Here is the source code for com.google.gwt.dev.javac.asm.CollectAnnotationData.java

Source

/*
 * Copyright 2009 Google Inc.
 *
 * Licensed 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 com.google.gwt.dev.javac.asm;

import com.google.gwt.dev.javac.asm.CollectClassData.AnnotationEnum;
import com.google.gwt.dev.util.StringInterner;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Opcodes;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Collects data from (possibly nested) annotations on a single entity.
 */
public class CollectAnnotationData extends AnnotationVisitor {

    /**
     * Holds annotation fields/values.
     */
    public static class AnnotationData {
        private final String desc;
        private final Map<String, Object> values = new HashMap<String, Object>();
        private final boolean visible;

        protected AnnotationData(String desc, boolean visible) {
            this.desc = StringInterner.get().intern(desc);
            this.visible = visible;
        }

        public void addValue(String name, Object value) {
            values.put(StringInterner.get().intern(name), value);
        }

        /**
         * @return the desc
         */
        public String getDesc() {
            return desc;
        }

        /**
         * @return the values
         */
        public Map<String, Object> getValues() {
            return values;
        }

        /**
         * @return the visible
         */
        public boolean isVisible() {
            return visible;
        }
    }

    /**
     * Collects data inside an array-valued annotation parameter.
     */
    public static class MyAnnotationArrayVisitor extends AnnotationVisitor {

        private final Callback<Object> callback;
        private final List<Object> values = new ArrayList<Object>();

        public MyAnnotationArrayVisitor(Callback<Object> callback) {
            super(Opcodes.ASM6);
            this.callback = callback;
        }

        @Override
        public void visit(String name, Object value) {
            values.add(value);
        }

        @Override
        public AnnotationVisitor visitAnnotation(String name, String desc) {
            // TODO(jat): what should visible be set to?
            return new CollectAnnotationData(desc, true, new Callback<CollectAnnotationData.AnnotationData>() {
                @Override
                public void call(CollectAnnotationData.AnnotationData value) {
                    values.add(value);
                }
            });
        }

        @Override
        public AnnotationVisitor visitArray(String name) {
            return new MyAnnotationArrayVisitor(new Callback<Object>() {
                @Override
                public void call(Object value) {
                    values.add(value);
                }
            });
        }

        @Override
        public void visitEnd() {
            callback.call(values.toArray());
        }

        @Override
        public void visitEnum(String name, String desc, String value) {
            values.add(new AnnotationEnum(desc, value));
        }
    }

    /**
     * Generic callback type taking a parameter.
     *
     * @param <T> type of the argument to the callback
     */
    private interface Callback<T> {

        /**
         * Invoke the callback.
         *
         * @param value value to pass to the callback.
         */
        void call(T value);
    }

    private final CollectAnnotationData.AnnotationData annotation;
    private final Callback<CollectAnnotationData.AnnotationData> callback;

    /**
     * Construct the collector.
     *
     * @param desc class descriptor of the annotation class
     * @param visible true if the annotation is visible at runtime
     */
    public CollectAnnotationData(String desc, boolean visible) {
        this(desc, visible, null);
    }

    /**
     * Construct the collector.
     *
     * @param desc class descriptor of the annotation class
     * @param visible true if the annotation is visible at runtime
     * @param callback callback to be called when the annotation is finished
     */
    CollectAnnotationData(String desc, boolean visible, Callback<CollectAnnotationData.AnnotationData> callback) {
        super(Opcodes.ASM6);
        annotation = new AnnotationData(desc, visible);
        this.callback = callback;
    }

    /**
     * @return the annotation data
     */
    public AnnotationData getAnnotation() {
        return annotation;
    }

    @Override
    public void visit(String name, Object value) {
        annotation.addValue(name, value);
    }

    @Override
    public AnnotationVisitor visitAnnotation(final String name, String desc) {
        // TODO(jat): what should visible be set to?
        return new CollectAnnotationData(desc, true, new Callback<CollectAnnotationData.AnnotationData>() {
            @Override
            public void call(CollectAnnotationData.AnnotationData value) {
                annotation.addValue(name, value);
            }
        });
    }

    @Override
    public AnnotationVisitor visitArray(final String name) {
        return new MyAnnotationArrayVisitor(new Callback<Object>() {

            /**
             * Called with an array of values.
             *
             * @param value
             */
            @Override
            public void call(Object value) {
                annotation.addValue(name, value);
            }
        });
    }

    @Override
    public void visitEnd() {
        if (callback != null) {
            callback.call(annotation);
        }
    }

    @Override
    public void visitEnum(String name, String desc, String value) {
        annotation.addValue(name, new AnnotationEnum(desc, value));
    }
}