    001    // Copyright 2011 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    // http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.plastic;
    016
    017    import java.lang.annotation.Annotation;
    018    import java.lang.reflect.Method;
    019    import java.util.List;
    020    import java.util.Set;
    021
    022    /**
    023     * The representation of a class while it is being instrumented and transformed. PlasticClass allows
    024     * for an imperative style of development: the PlasticClass is provided to other objects; they can query it
    025     * for relevant fields or methods, and invoke methods that modify the class in various ways. Ultimately, the
    026     * end result is a {@link ClassInstantiator} used to create instances of the fully instrumented and transformed class.
    027     * <p/>
    028     * The terminology is that a class that is being transformed is "plastic", but the end result is a normal concrete class
    029     * (albeit in a different class loader).
    030     * <p/>
    031     * Implements {@link AnnotationAccess} to provide access to annotations on the type itself.
    032     * <p/>
    033     * This class is expressly <em>not thread safe</em>; only a single thread should be responsible for operating on a
    034     * PlasticClass.
    035     * <p/>
    036     * TODO: what about annotation inheritance?
    037     */
    038    @SuppressWarnings("rawtypes")
    039    public interface PlasticClass extends AnnotationAccess
    040    {
    041        /**
    042         * Returns the fully qualified class name of the class being transformed.
    043         */
    044        String getClassName();
    045
    046        /**
    047         * Matches all fields (claimed or not) that have the given annotation. Returns the fields in sorted order.
    048         *
    049         * @return Unmodifiable List of fields.
    050         */
    051        <T extends Annotation> List<PlasticField> getFieldsWithAnnotation(Class<T> annotationType);
    052
    053        /**
    054         * Returns all non-introduced fields, in sorted order by name.
    055         *
    056         * @return Unmodifiable list of fields.
    057         */
    058        List<PlasticField> getAllFields();
    059
    060        /**
    061         * Returns all unclaimed fields, in sorted order by name. This does not include introduced fields.
    062         *
    063         * @return Unmodifiable list of fields.
    064         * @see PlasticField#claim(Object)
    065         */
    066        List<PlasticField> getUnclaimedFields();
    067
    068        /**
    069         * Introduces a new private field into the class.
    070         *
    071         * @param typeName      the Java class name for the field, or (possibly) a primitive type name or an array
    072         * @param suggestedName the suggested name for the field, which may be modified to ensure that the field name
    073         *                      is unique
    074         * @return PlasticField for the introduced field
    075         */
    076        PlasticField introduceField(String typeName, String suggestedName);
    077
    078        /**
    079         * Convenience method that uses a Java class rather than a type name.
    080         */
    081        PlasticField introduceField(Class fieldType, String suggestedName);
    082
    083        /**
    084         * Introduces a new private method into the class, ensuring that the method name is unique.
    085         *
    086         * @param typeName       return type of method
    087         * @param suggestedName  suggested name for the method; the actual method name may be modified to ensure uniqueness
    088         * @param argumentTypes  types of any arguments (may be null)
    089         * @param exceptionTypes type of any checked exceptions (may be null)
    090         * @return new method, with default implementation
    091         */
    092        PlasticMethod introducePrivateMethod(String typeName, String suggestedName, String[] argumentTypes,
    093                                             String[] exceptionTypes);
    094
    095        /**
    096         * Matches methods with the given annotation.
    097         *
    098         * @return Unmodifiable list of methods, in sorted order.
    099         */
    100        <T extends Annotation> List<PlasticMethod> getMethodsWithAnnotation(Class<T> annotationType);
    101
    102        /**
    103         * Returns all methods of the class, in sorted order. This does not include static methods,
    104         * or any {@linkplain #introduceMethod(MethodDescription) introduced methods}.
    105         *
    106         * @return Unmodifiable list of methods.
    107         */
    108        List<PlasticMethod> getMethods();
    109
    110        /**
    111         * Returns an existing method declared in this class, or introduces a new method into this class.
    112         * The method is created with default behavior. If the method overrides a non-private, non-abstract method
    113         * implemented in a <em>transformed</em> super class, the the default behavior is to invoke that method and return
    114         * its value. Otherwise, the default behavior is to ignore parameters and return 0, false, or null. Void methods
    115         * will invoke the super-class implementation (if it exists) and return no value.
    116         * <p/>
    117         * It is allowed for the method description to indicate an abstract method; however the abstract flag will be
    118         * removed, and a non-abstract method will be created.
    119         *
    120         * @param description describes the method name, visibility, return value, etc.
    121         * @return a new (or previously created) PlasticMethod for the method
    122         * @throws IllegalArgumentException if the method is abstract or static
    123         */
    124        PlasticMethod introduceMethod(MethodDescription description);
    125
    126        /**
    127         * Returns an existing method declared in this class, or introduces a new method into this class.
    128         * The method is created with default behavior.
    129         * <p/>
    130         * It is allowed for the method description to indicate an abstract method; however the abstract flag will be
    131         * removed, and a non-abstract method will be created.
    132         *
    133         * @param description describes the method name, visibility, return value, etc.
    134         * @param callback    used to create the implementation of the method
    135         * @return a new (or previously created) PlasticMethod for the method
    136         * @throws IllegalArgumentException if the method is abstract or static
    137         */
    138        PlasticMethod introduceMethod(MethodDescription description, InstructionBuilderCallback callback);
    139
    140        /**
    141         * A convenience that creates a {@link MethodDescription} from the Method and introduces that. This is often
    142         * invoked when walking the methods of an interface and introducing each of those methods.
    143         * <p/>
    144         * Introduced methods are always concrete, not abstract. The abstract flag on the method modifiers will always be
    145         * stripped off, which is handy when {@linkplain #introduceInterface(Class) introducing methods from an interface}.
    146         *
    147         * @param method to introduce
    148         * @return new (or previously created) PlasticMethod
    149         */
    150        PlasticMethod introduceMethod(Method method);
    151
    152        /**
    153         * Introduces each method defined by the interface into the class. Determines which new methods must
    154         * be introduced in order to ensure that all methods of the interface are implemented. The newly introduced methods,
    155         * if any, are returned.
    156         */
    157        Set<PlasticMethod> introduceInterface(Class interfaceType);
    158
    159        /**
    160         * Introduces the interface, and then invokes {@link PlasticMethod#delegateTo(PlasticField)} on each method
    161         * defined by the interface.
    162         *
    163         * @param interfaceType defines the interface to proxy
    164         * @param field         field containing an object to delegate to
    165         * @return this plastic class, for further configuration
    166         */
    167        PlasticClass proxyInterface(Class interfaceType, PlasticField field);
    168
    169        /**
    170         * Conditionally adds an implementation of <code>toString()</code> to the class, but only if it is not already
    171         * present in the class, or in a (transformed) super-class.
    172         *
    173         * @param toStringValue the fixed value to be returned from invoking toString()
    174         * @return this plastic class, for further configuration
    175         */
    176        PlasticClass addToString(String toStringValue);
    177
    178        /**
    179         * Returns true if this class has an implementation of the indicated method, or a super-class provides
    180         * a non-abstract implementation.
    181         */
    182        boolean isMethodImplemented(MethodDescription description);
    183
    184        /**
    185         * Returns true if this class, or a super-class, implements the indicated interface.
    186         *
    187         * @param interfaceType
    188         * @return true if the interface is implemented
    189         */
    190        boolean isInterfaceImplemented(Class interfaceType);
    191
    192        /**
    193         * Returns the name of the super-class of the class being transformed.
    194         */
    195        String getSuperClassName();
    196
    197        /**
    198         * Adds the callback for execution when an instance of the class is instantiated.
    199         *
    200         * @param callback to execute at instance construction time
    201         */
    202        PlasticClass onConstruct(ConstructorCallback callback);
    203    }