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/*
 *  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 libcore.reflect;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.annotation.AnnotationTypeMismatchException;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Arrays;

/**
 * This class represents member element of an annotation.
 * It consists of name and value, supplemented with element
 * definition information (such as declared type of element).
 * 
The value may be one of the following types: *
    *
  • boxed primitive *
  • Class *
  • enum constant *
  • annotation (nested) *
  • one-dimensional array of the above *
  • Throwable *
* The last type is specific for this implementation; a Throwable value * means that the error occured during parsing or resolution of corresponding * class-data structures and throwing is delayed until the element * is requested for value. * * @see AnnotationFactory * * @author Alexey V. Varlamov, Serguei S. Zapreyev * @version $Revision$ */ @SuppressWarnings({"serial"}) public final class AnnotationMember implements Serializable { /** * Tag description of a Throwable value type. */ protected static final char ERROR = '!'; /** * Tag description of an array value type. */ protected static final char ARRAY = '['; /** * Tag description of all value types except arrays and Throwables. */ protected static final char OTHER = '*'; // public static final char INT = 'I'; // public static final char CHAR = 'C'; // public static final char DOUBLE = 'D'; // public static final char FLOAT = 'F'; // public static final char BYTE = 'B'; // public static final char LONG = 'J'; // public static final char SHORT = 'S'; // public static final char BOOL = 'Z'; // public static final char CLASS = 'c'; // public static final char ENUM = 'e'; // public static final char ANTN = '@'; private enum DefaultValues {NO_VALUE} /** * Singleton representing missing element value. */ protected static final Object NO_VALUE = DefaultValues.NO_VALUE; protected final String name; protected final Object value; // a primitive value is wrapped to the corresponding wrapper class protected final char tag; // no sense to serialize definition info as it can be changed arbitrarily protected transient Class elementType; protected transient Method definingMethod; /** * Creates a new element with specified name and value. * Definition info will be provided later when this * element becomes actual annotation member. * @param name element name, must not be null * @param val element value, should be of addmissible type, * as specified in the description of this class * * @see #setDefinition(AnnotationMember) */ public AnnotationMember(String name, Object val) { this.name = name; value = val == null ? NO_VALUE : val; if (value instanceof Throwable) { tag = ERROR; } else if (value.getClass().isArray()) { tag = ARRAY; } else { tag = OTHER; } } /** * Creates the completely defined element. * @param name element name, must not be null * @param value element value, should be of addmissible type, * as specified in the description of this class * @param m element-defining method, reflected on the annotation type * @param type declared type of this element * (return type of the defining method) */ public AnnotationMember(String name, Object val, Class type, Method m) { this(name, val); definingMethod = m; if (type == int.class) { elementType = Integer.class; } else if (type == boolean.class) { elementType = Boolean.class; } else if (type == char.class) { elementType = Character.class; } else if (type == float.class) { elementType = Float.class; } else if (type == double.class) { elementType = Double.class; } else if (type == long.class) { elementType = Long.class; } else if (type == short.class) { elementType = Short.class; } else if (type == byte.class) { elementType = Byte.class; } else { elementType = type; } } /** * Fills in element's definition info and returns this. */ protected AnnotationMember setDefinition(AnnotationMember copy) { definingMethod = copy.definingMethod; elementType = copy.elementType; return this; } /** * Returns readable description of this annotation value. */ public String toString() { if (tag == ARRAY) { StringBuilder sb = new StringBuilder(80); sb.append(name).append("=["); int len = Array.getLength(value); for (int i = 0; i < len; i++) { if (i != 0) sb.append(", "); sb.append(Array.get(value, i)); } return sb.append("]").toString(); } else { return name+ "=" +value; } } /** * Returns true if the specified object represents equal element * (equivalent name-value pair). *
A special case is the contained Throwable value; it is considered * transcendent so no other element would be equal. * @return true if passed object is equivalent element representation, * false otherwise * @see #equalArrayValue(Object) * @see java.lang.annotation.Annotation#equals(Object) */ public boolean equals(Object obj) { if (obj == this) { // not a mere optimization, // this is needed for consistency with hashCode() return true; } if (obj instanceof AnnotationMember) { AnnotationMember that = (AnnotationMember)obj; if (name.equals(that.name) && tag == that.tag) { if (tag == ARRAY) { return equalArrayValue(that.value); } else if (tag == ERROR) { // undefined value is incomparable (transcendent) return false; } else { return value.equals(that.value); } } } return false; } /** * Returns true if the contained value and a passed object are equal arrays, * false otherwise. Appropriate overloaded method of Arrays.equals() * is used for equality testing. * @see java.util.Arrays#equals(java.lang.Object[], java.lang.Object[]) * @return true if the value is array and is equal to specified object, * false otherwise */ public boolean equalArrayValue(Object otherValue) { if (value instanceof Object[] && otherValue instanceof Object[]) { return Arrays.equals((Object[])value, (Object[])otherValue); } Class type = value.getClass(); if (type != otherValue.getClass()) { return false; } if (type == int[].class) { return Arrays.equals((int[])value, (int[])otherValue); } else if (type == byte[].class) { return Arrays.equals((byte[])value, (byte[])otherValue); } else if (type == short[].class) { return Arrays.equals((short[])value, (short[])otherValue); } else if (type == long[].class) { return Arrays.equals((long[])value, (long[])otherValue); } else if (type == char[].class) { return Arrays.equals((char[])value, (char[])otherValue); } else if (type == boolean[].class) { return Arrays.equals((boolean[])value, (boolean[])otherValue); } else if (type == float[].class) { return Arrays.equals((float[])value, (float[])otherValue); } else if (type == double[].class) { return Arrays.equals((double[])value, (double[])otherValue); } return false; } /** * Computes hash code of this element. The formula is as follows: * (name.hashCode() * 127) ^ value.hashCode() *
If value is an array, one of overloaded Arrays.hashCode() * methods is used. * @return the hash code * @see java.util.Arrays#hashCode(java.lang.Object[]) * @see java.lang.annotation.Annotation#hashCode() */ public int hashCode() { int hash = name.hashCode() * 127; if (tag == ARRAY) { Class type = value.getClass(); if (type == int[].class) { return hash ^ Arrays.hashCode((int[])value); } else if (type == byte[].class) { return hash ^ Arrays.hashCode((byte[])value); } else if (type == short[].class) { return hash ^ Arrays.hashCode((short[])value); } else if (type == long[].class) { return hash ^ Arrays.hashCode((long[])value); } else if (type == char[].class) { return hash ^ Arrays.hashCode((char[])value); } else if (type == boolean[].class) { return hash ^ Arrays.hashCode((boolean[])value); } else if (type == float[].class) { return hash ^ Arrays.hashCode((float[])value); } else if (type == double[].class) { return hash ^ Arrays.hashCode((double[])value); } return hash ^ Arrays.hashCode((Object[])value); } else { return hash ^ value.hashCode(); } } /** * Throws contained error (if any) with a renewed stack trace. */ public void rethrowError() throws Throwable { if (tag == ERROR) { // need to throw cloned exception for thread safety // besides it is better to provide actual stack trace // rather than recorded during parsing // first check for expected types if (value instanceof TypeNotPresentException) { TypeNotPresentException tnpe = (TypeNotPresentException)value; throw new TypeNotPresentException(tnpe.typeName(), tnpe.getCause()); } else if (value instanceof EnumConstantNotPresentException) { EnumConstantNotPresentException ecnpe = (EnumConstantNotPresentException)value; throw new EnumConstantNotPresentException(ecnpe.enumType(), ecnpe.constantName()); } else if (value instanceof ArrayStoreException) { ArrayStoreException ase = (ArrayStoreException)value; throw new ArrayStoreException(ase.getMessage()); } // got some other error, have to go with deep cloning // via serialization mechanism Throwable error = (Throwable)value; StackTraceElement[] ste = error.getStackTrace(); ByteArrayOutputStream bos = new ByteArrayOutputStream( ste == null ? 512 : (ste.length + 1) * 80); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(error); oos.flush(); oos.close(); ByteArrayInputStream bis = new ByteArrayInputStream(bos .toByteArray()); ObjectInputStream ois = new ObjectInputStream(bis); error = (Throwable)ois.readObject(); ois.close(); throw error; } } /** * Validates contained value against its member definition * and if ok returns the value. * Otherwise, if the value type mismatches definition * or the value itself describes an error, * throws appropriate exception. *
Note, this method may return null if this element was constructed * with such value. * * @see #rethrowError() * @see #copyValue() * @return actual valid value or null if no value */ public Object validateValue() throws Throwable { if (tag == ERROR) { rethrowError(); } if (value == NO_VALUE) { return null; } if (elementType == value.getClass() || elementType.isInstance(value)) { // nested annotation value return copyValue(); } else { throw new AnnotationTypeMismatchException(definingMethod, value.getClass().getName()); } } /** * Provides mutation-safe access to contained value. That is, caller is free * to modify the returned value, it will not affect the contained data value. * @return cloned value if it is mutable or the original immutable value */ public Object copyValue() throws Throwable { if (tag != ARRAY || Array.getLength(value) == 0) { return value; } Class type = value.getClass(); if (type == int[].class) { return ((int[])value).clone(); } else if (type == byte[].class) { return ((byte[])value).clone(); } else if (type == short[].class) { return ((short[])value).clone(); } else if (type == long[].class) { return ((long[])value).clone(); } else if (type == char[].class) { return ((char[])value).clone(); } else if (type == boolean[].class) { return ((boolean[])value).clone(); } else if (type == float[].class) { return ((float[])value).clone(); } else if (type == double[].class) { return ((double[])value).clone(); } return ((Object[])value).clone(); } }




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