org.springframework.binding.method.MethodKey Maven / Gradle / Ivy
/*
* Copyright 2004-2008 the original author or authors.
*
* 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 org.springframework.binding.method;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
/**
* A helper for resolving and caching a Java method by reflection.
*
* @author Keith Donald
*/
public class MethodKey implements Serializable {
/**
* The class the method is a member of.
*/
private Class declaredType;
/**
* The method name.
*/
private String methodName;
/**
* The method's actual parameter types. Could contain null values if the user did not specify a parameter type for
* the corresponding parameter
*/
private Class[] parameterTypes;
/**
* A cached handle to the resolved method (may be null).
*/
private transient Method method;
/**
* Create a new method key.
* @param declaredType the class the method is a member of
* @param methodName the method name
* @param parameterTypes the method's parameter types, or null if the method has no parameters
*/
public MethodKey(Class declaredType, String methodName, Class[] parameterTypes) {
Assert.notNull(declaredType, "The method's declared type is required");
Assert.notNull(methodName, "The method name is required");
this.declaredType = declaredType;
this.methodName = methodName;
this.parameterTypes = parameterTypes;
}
/**
* Return the class the method is a member of.
*/
public Class getDeclaredType() {
return declaredType;
}
/**
* Returns the method name.
*/
public String getMethodName() {
return methodName;
}
/**
* Returns the method parameter types. Could contain null values if no type was specified for the corresponding
* parameter.
*/
public Class[] getParameterTypes() {
return parameterTypes;
}
/**
* Returns the keyed method, resolving it if necessary via reflection.
*/
public Method getMethod() throws InvalidMethodKeyException {
if (method == null) {
method = resolveMethod();
}
return method;
}
// internal helpers
/**
* Resolve the keyed method.
*/
protected Method resolveMethod() throws InvalidMethodKeyException {
try {
return declaredType.getMethod(methodName, parameterTypes);
} catch (NoSuchMethodException e) {
Method method = findMethodConsiderAssignableParameterTypes();
if (method != null) {
return method;
} else {
throw new InvalidMethodKeyException(this, e);
}
}
}
/**
* Find the keyed method using 'relaxed' typing.
*/
protected Method findMethodConsiderAssignableParameterTypes() {
Method[] candidateMethods = getDeclaredType().getMethods();
for (int i = 0; i < candidateMethods.length; i++) {
if (candidateMethods[i].getName().equals(methodName)) {
// Check if the method has the correct number of parameters.
Class[] candidateParameterTypes = candidateMethods[i].getParameterTypes();
if (candidateParameterTypes.length == parameterTypes.length) {
int numberOfCorrectArguments = 0;
for (int j = 0; j < candidateParameterTypes.length; j++) {
// Check if the candidate type is assignable to the sig
// parameter type.
Class candidateType = candidateParameterTypes[j];
Class parameterType = parameterTypes[j];
if (parameterType != null) {
if (isAssignable(candidateType, parameterType)) {
numberOfCorrectArguments++;
}
} else {
// just match on a null param type (effectively 'any')
numberOfCorrectArguments++;
}
}
if (numberOfCorrectArguments == parameterTypes.length) {
return candidateMethods[i];
}
}
}
}
return null;
}
public boolean equals(Object obj) {
if (!(obj instanceof MethodKey)) {
return false;
}
MethodKey other = (MethodKey) obj;
return declaredType.equals(other.declaredType) && methodName.equals(other.methodName)
&& parameterTypesEqual(other.parameterTypes);
}
private boolean parameterTypesEqual(Class[] other) {
if (parameterTypes == other) {
return true;
}
if (parameterTypes.length != other.length) {
return false;
}
for (int i = 0; i < this.parameterTypes.length; i++) {
if (!ObjectUtils.nullSafeEquals(parameterTypes[i], other[i])) {
return false;
}
}
return true;
}
public int hashCode() {
return declaredType.hashCode() + methodName.hashCode() + parameterTypesHash();
}
private int parameterTypesHash() {
if (parameterTypes == null) {
return 0;
}
int hash = 0;
for (int i = 0; i < parameterTypes.length; i++) {
Class parameterType = parameterTypes[i];
if (parameterType != null) {
hash += parameterTypes[i].hashCode();
}
}
return hash;
}
public String toString() {
return methodName + "(" + parameterTypesString() + ")";
}
/**
* Convenience method that returns the parameter types describing the signature of the method as a string.
*/
private String parameterTypesString() {
StringBuffer parameterTypesString = new StringBuffer();
for (int i = 0; i < parameterTypes.length; i++) {
if (parameterTypes[i] == null) {
parameterTypesString.append("");
} else {
parameterTypesString.append(ClassUtils.getShortName(parameterTypes[i]));
}
if (i < parameterTypes.length - 1) {
parameterTypesString.append(',');
}
}
return parameterTypesString.toString();
}
// internal helpers
/**
* Determine if the given target type is assignable from the given value type, assuming setting by reflection.
* Considers primitive wrapper classes as assignable to the corresponding primitive types.
*
* NOTE: Pulled from ClassUtils in Spring 2.0 for 1.2.8 compatability.
* @param targetType the target type
* @param valueType the value type that should be assigned to the target type
* @return if the target type is assignable from the value type
*/
private static boolean isAssignable(Class targetType, Class valueType) {
return (targetType.isAssignableFrom(valueType) || targetType.equals(primitiveWrapperTypeMap.get(valueType)));
}
/**
* Map with primitive wrapper type as key and corresponding primitive type as value, for example: Integer.class ->
* int.class.
*/
private static final Map primitiveWrapperTypeMap = new HashMap(8);
static {
primitiveWrapperTypeMap.put(Boolean.class, boolean.class);
primitiveWrapperTypeMap.put(Byte.class, byte.class);
primitiveWrapperTypeMap.put(Character.class, char.class);
primitiveWrapperTypeMap.put(Double.class, double.class);
primitiveWrapperTypeMap.put(Float.class, float.class);
primitiveWrapperTypeMap.put(Integer.class, int.class);
primitiveWrapperTypeMap.put(Long.class, long.class);
primitiveWrapperTypeMap.put(Short.class, short.class);
}
}