freemarker.ext.beans.SimpleMethodModel Maven / Gradle / Ivy
/*
* 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 freemarker.ext.beans;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Collections;
import java.util.List;
import freemarker.core._DelayedFTLTypeDescription;
import freemarker.core._DelayedToString;
import freemarker.core._ErrorDescriptionBuilder;
import freemarker.core._TemplateModelException;
import freemarker.core._UnexpectedTypeErrorExplainerTemplateModel;
import freemarker.template.SimpleNumber;
import freemarker.template.TemplateMethodModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateSequenceModel;
/**
* A class that will wrap a reflected method call into a
* {@link freemarker.template.TemplateMethodModel} interface.
* It is used by {@link BeanModel} to wrap reflected method calls
* for non-overloaded methods.
*/
public final class SimpleMethodModel extends SimpleMethod
implements
TemplateMethodModelEx,
TemplateSequenceModel,
_UnexpectedTypeErrorExplainerTemplateModel {
private final Object object;
private final BeansWrapper wrapper;
/**
* Creates a model for a specific method on a specific object.
* @param object the object to call the method on, or {@code null} for a static method.
* @param method the method that will be invoked.
* @param argTypes Either pass in {@code Method#getParameterTypes() method.getParameterTypes()} here,
* or reuse an earlier result of that call (for speed). Not {@code null}.
*/
SimpleMethodModel(Object object, Method method, Class[] argTypes,
BeansWrapper wrapper) {
super(method, argTypes);
this.object = object;
this.wrapper = wrapper;
}
/**
* Invokes the method, passing it the arguments from the list.
*/
public Object exec(List arguments)
throws TemplateModelException {
try {
return wrapper.invokeMethod(object, (Method) getMember(),
unwrapArguments(arguments, wrapper));
} catch (TemplateModelException e) {
throw e;
} catch (Exception e) {
throw _MethodUtil.newInvocationTemplateModelException(object, getMember(), e);
}
}
public TemplateModel get(int index) throws TemplateModelException {
return (TemplateModel) exec(Collections.singletonList(
new SimpleNumber(Integer.valueOf(index))));
}
public int size() throws TemplateModelException {
throw new _TemplateModelException(
new _ErrorDescriptionBuilder(
"Getting the number of items or listing the items is not supported on this ",
new _DelayedFTLTypeDescription(this), " value, because this value wraps the following Java method, "
+ "not a real listable value: ", new _DelayedToString(getMember()))
.tips(
"Maybe you should to call this method first and then do something with its return value.",
"obj.someMethod(i) and obj.someMethod[i] does the same for this method, hence it's a "
+ "\"+sequence\"."));
}
@Override
public String toString() {
return getMember().toString();
}
/**
* Implementation of experimental interface; don't use it, no backward compatibility guarantee!
*/
public Object[] explainTypeError(Class[] expectedClasses) {
final Member member = getMember();
if (!(member instanceof Method)) {
return null; // This shouldn't occur
}
Method m = (Method) member;
final Class returnType = m.getReturnType();
if (returnType == null || returnType == void.class || returnType == Void.class) {
return null; // Calling it won't help
}
String mName = m.getName();
if (mName.startsWith("get") && mName.length() > 3 && Character.isUpperCase(mName.charAt(3))
&& (m.getParameterTypes().length == 0)) {
return new Object[] {
"Maybe using obj.something instead of obj.getSomething will yield the desired value." };
} else if (mName.startsWith("is") && mName.length() > 2 && Character.isUpperCase(mName.charAt(2))
&& (m.getParameterTypes().length == 0)) {
return new Object[] {
"Maybe using obj.something instead of obj.isSomething will yield the desired value." };
} else {
return new Object[] {
"Maybe using obj.something(",
(m.getParameterTypes().length != 0 ? "params" : ""),
") instead of obj.something will yield the desired value" };
}
}
}