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Diffstat (limited to 'sca-java-1.x/tags/java-stable-20060304/sca/core/src/main/java/org/apache/tuscany/core/config/JavaIntrospectionHelper.java')
| -rw-r--r-- | sca-java-1.x/tags/java-stable-20060304/sca/core/src/main/java/org/apache/tuscany/core/config/JavaIntrospectionHelper.java | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/sca-java-1.x/tags/java-stable-20060304/sca/core/src/main/java/org/apache/tuscany/core/config/JavaIntrospectionHelper.java b/sca-java-1.x/tags/java-stable-20060304/sca/core/src/main/java/org/apache/tuscany/core/config/JavaIntrospectionHelper.java new file mode 100644 index 0000000000..c10ff82310 --- /dev/null +++ b/sca-java-1.x/tags/java-stable-20060304/sca/core/src/main/java/org/apache/tuscany/core/config/JavaIntrospectionHelper.java @@ -0,0 +1,349 @@ +package org.apache.tuscany.core.config; + +import java.lang.reflect.AccessibleObject; +import java.lang.reflect.Constructor; +import java.lang.reflect.Field; +import java.lang.reflect.Method; +import java.util.ArrayList; +import java.util.HashSet; +import java.util.List; +import java.util.Set; + +/** + * Implements various reflection-related operations + * + * @version $Rev$ $Date$ + */ +public class JavaIntrospectionHelper { + + private static final Class[] EMPTY_CLASS_ARRY = new Class[0]; + + // ---------------------------------- + // Constructors + // ---------------------------------- + + /** + * Hide the constructor + */ + private JavaIntrospectionHelper() { + } + + // ---------------------------------- + // Methods + // ---------------------------------- + + /** + * Returns a collection of public, private, protected, or default fields declared by a class or one of its + * supertypes + */ + public static Set<Field> getAllFields(Class pClass) { + return getAllFields(pClass, new HashSet<Field>()); + } + + /** + * Recursively evaluates the type hierachy to return all fields on a given type + * + * @spec This raises an interesting issue - do we allow injection on private supertype fields in a subtype even if + * they are annotated? + */ + private static Set<Field> getAllFields(Class pClass, Set<Field> fields) { + if (pClass == null || pClass.isArray() || Object.class.equals(pClass)) { + return fields; + } + fields = getAllFields(pClass.getSuperclass(), fields); + Field[] declaredFields = pClass.getDeclaredFields(); + for (int i = 0; i < declaredFields.length; i++) { + declaredFields[i].setAccessible(true); // ignore Java accessibility + fields.add(declaredFields[i]); + } + return fields; + } + + /** + * Returns a collection of public, private, protected, or default methods declared by a class or one of its + * supertypes. Note that overriden methods will not be returned in the collection (i.e. only the method override + * will be). <p/> This method can potentially be expensive as reflection information is not cached. It is assumed + * that this method will be used during a configuration phase. + */ + public static Set<Method> getAllUniqueMethods(Class pClass) { + return getAllUniqueMethods(pClass, new HashSet<Method>()); + } + + /** + * Recursively evaluates the type hierarchy to return all unique methods + */ + private static Set<Method> getAllUniqueMethods(Class pClass, Set<Method> methods) { + if (pClass == null || pClass.isArray() || Object.class.equals(pClass)) { + return methods; + } + // we first evaluate methods of the subclass and then move to the parent + Method[] declaredMethods = pClass.getDeclaredMethods(); + for (int i = 0; i < declaredMethods.length; i++) { + if (methods.size() == 0) { + methods.add(declaredMethods[i]); + } else { + List temp = new ArrayList(); + boolean matched = false; + for (Method method : methods) { + // only add if not already in the set from a supclass (i.e. the + // method is not overrided) + if (exactMethodMatch(declaredMethods[i], method)) { + matched = true; + break; + } + } + if (!matched) { + // TODO ignore Java accessibility + declaredMethods[i].setAccessible(true); + temp.add(declaredMethods[i]); + + } + methods.addAll(temp); + temp.clear(); + } + } + // evaluate class hierarchy - this is done last to track inherited methods + methods = getAllUniqueMethods(pClass.getSuperclass(), methods); + return methods; + } + + /** + * Finds the closest matching field with the given name, that is, a field of the exact specified type or, + * alternately, of a supertype. + * + * @param name the name of the field + * @param type the field type + * @param fields the collection of fields to search + * @return the matching field or null if not found + * @throws NoSuchFieldException if no field found + */ + public static Field findClosestMatchingField(String name, Class type, Set<Field> fields) { + Field candidate = null; + for (Field field : fields) { + if (field.getName().equals(name)) { + if (field.getType().equals(type)) { + return field; // exact match + } else if (field.getType().isAssignableFrom(type) + || (field.getType().isPrimitive() && primitiveAssignable(field.getType(), type))) { + // We could have the situation where a field parameter is a primitive and the demarshalled value is + // an object counterpart (e.g. Integer and int) + // @spec issue + // either an interface or super class, so keep a reference until + // we know there are no closer types + candidate = field; + } + } + } + if (candidate != null) { + return candidate; + } else { + return null; + } + } + + /** + * Finds the closest matching method with the given name, that is, a method taking the exact parameter types or, + * alternately, parameter supertypes. + * + * @param name the name of the method + * @param types the method parameter types + * @param methods the collection of methods to search + * @return the matching method or null if not found + * @throws NoSuchFieldException if no field found + */ + public static Method findClosestMatchingMethod(String name, Class[] types, Set<Method> methods) { + if (types == null) { + types = EMPTY_CLASS_ARRY; + } + Method candidate = null; + for (Method method : methods) { + if (method.getName().equals(name) && method.getParameterTypes().length == types.length) { + Class[] params = method.getParameterTypes(); + boolean disqualify = false; + boolean exactMatch = true; + for (int i = 0; i < params.length; i++) { + if (!params[i].equals(types[i]) && !params[i].isAssignableFrom(types[i])) { + // no match + disqualify = true; + exactMatch = false; + break; + } else if (!params[i].equals(types[i]) && params[i].isAssignableFrom(types[i])) { + // not exact match + exactMatch = false; + } + } + if (disqualify) { + continue; + } else if (exactMatch) { + return method; + } else { + candidate = method; + } + } + } + if (candidate != null) { + return candidate; + } else { + return null; + } + } + + /** + * Returns a field or method defined in the given class or its superclasses matching a literal name and parameter + * types <p/> This method can potentially be expensive as reflection information is not cached. It is assumed that + * this method will be used during a configuration phase. + * + * @param clazz the class to introspect + * @param propertName the literal name of the property (i.e. JavaBean conventions are not applied) + * @param paramTypes the parameter types for a method or null for fields or methods with no parameters + * @return the field, method or null + */ + public static AccessibleObject getBeanProperty(Class clazz, String propertName, Class[] paramTypes) { + + Set<Method> methods = getAllUniqueMethods(clazz); + for (Method method : methods) { + if (method.getName().equals(propertName)) { + Class[] types = method.getParameterTypes(); + if (types.length == 0 && paramTypes == null) { + return method; + } else if (types.length != 0 && paramTypes == null) { + break; + } else if (types.length == paramTypes.length) { + for (int n = 0; n < types.length - 1; n++) { + if (!types[n].equals(paramTypes[n]) || !types[n].isAssignableFrom(paramTypes[n])) { + break; + } + } + return method; + } + } + } + + Set<Field> fields = getAllFields(clazz); + for (Field field : fields) { + if (field.getName().equals(propertName)) { + return field; + } + } + return null; + } + + /** + * Determines if two methods "match" - that is, they have the same method names and exact parameter types (one is + * not a supertype of the other) + */ + public static boolean exactMethodMatch(Method method1, Method method2) { + if (!method1.getName().equals(method2.getName())) { + return false; + } + Class[] types1 = method1.getParameterTypes(); + Class[] types2 = method2.getParameterTypes(); + if (types1.length == 0 && types2.length == 0) { + return true; + } else if (types1.length == types2.length) { + for (int n = 0; n < types1.length; n++) { + if (!types1[n].equals(types2[n])) { + return false; + } + } + return true; + } + return false; + } + + public static Constructor getDefaultConstructor(Class clazz) throws NoSuchMethodException { + return clazz.getConstructor((Class[]) null); + } + + /** + * Loads a class corresponding to the class name using the current context class loader. + * + * @throws ClassNotFoundException if the class was not found on the classpath + */ + public static Class loadClass(String pName) throws ClassNotFoundException { + ClassLoader loader = Thread.currentThread().getContextClassLoader(); + return Class.forName(pName, true, loader); + } + + /** + * Returns the simple name of a class - i.e. the class name devoid of its package qualifier + * + * @param implClass + * @return + */ + public static String getBaseName(Class<?> implClass) { + String baseName = implClass.getName(); + int lastDot = baseName.lastIndexOf('.'); + if (lastDot != -1) { + baseName = baseName.substring(lastDot + 1); + } + return baseName; + } + + public static boolean isImmutable(Class clazz) { + return (String.class == clazz || clazz.isPrimitive() || Number.class.isAssignableFrom(clazz) + || Boolean.class.isAssignableFrom(clazz) || Character.class.isAssignableFrom(clazz) || Byte.class + .isAssignableFrom(clazz)); + } + + /** + * Takes a property name and converts it to a getter method name according to JavaBean conventions. For example, + * property <code>foo<code> is returned as <code>getFoo</code> + */ + public static String toGetter(String name) { + return "get" + name.toUpperCase().substring(0, 1) + name.substring(1); + } + + /** + * Takes a setter or getter method name and converts it to a property name according to JavaBean conventions. For + * example, <code>setFoo(var)</code> is returned as property <code>foo<code> + */ + public static String toPropertyName(String name) { + return name.substring(3, 4).toLowerCase() + name.substring(4); + } + + /** + * Takes a property name and converts it to a setter method name according to JavaBean conventions. For example, the + * property <code>foo<code> is returned as <code>setFoo(var)</code> + */ + public static String toSetter(String name) { + return "set" + name.toUpperCase().substring(0, 1) + name.substring(1); + } + + /** + * Compares a two types, assuming one is a primitive, to dtermine if the other is its object counterpart + */ + private static boolean primitiveAssignable(Class memberType, Class param) { + if (memberType == Integer.class) { + return (param == Integer.TYPE); + } else if (memberType == Double.class) { + return (param == Double.TYPE); + } else if (memberType == Float.class) { + return (param == Float.TYPE); + } else if (memberType == Short.class) { + return (param == Short.TYPE); + } else if (memberType == Character.class) { + return (param == Character.TYPE); + } else if (memberType == Boolean.class) { + return (param == Boolean.TYPE); + } else if (memberType == Byte.class) { + return (param == Byte.TYPE); + } else if (param == Integer.class) { + return (memberType == Integer.TYPE); + } else if (param == Double.class) { + return (memberType == Double.TYPE); + } else if (param == Float.class) { + return (memberType == Float.TYPE); + } else if (param == Short.class) { + return (memberType == Short.TYPE); + } else if (param == Character.class) { + return (memberType == Character.TYPE); + } else if (param == Boolean.class) { + return (memberType == Boolean.TYPE); + } else if (param == Byte.class) { + return (memberType == Byte.TYPE); + } else { + return false; + } + } +} |