/*
* Copyright 2011-2012 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.shell.converters;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.shell.core.Completion;
import org.springframework.shell.core.Converter;
import org.springframework.shell.core.MethodTarget;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* A simple {@link Converter} for those classes which provide public static fields to represent possible textual values.
*
* @author Stefan Schmidt
* @author Ben Alex
* @since 1.0
*/
@Component
public class StaticFieldConverterImpl implements StaticFieldConverter {
// Fields
private final Map<Class<?>, Map<String, Field>> fields = new HashMap<Class<?>, Map<String, Field>>();
@Override
public void add(final Class<?> clazz) {
Assert.notNull(clazz, "A class to provide conversion services is required");
Assert.isNull(fields.get(clazz), "Class '" + clazz + "' is already registered for completion services");
Map<String, Field> ffields = new HashMap<String, Field>();
for (Field field : clazz.getFields()) {
int modifier = field.getModifiers();
if (Modifier.isStatic(modifier) && Modifier.isPublic(modifier)) {
ffields.put(field.getName(), field);
}
}
Assert.notEmpty(ffields, "Zero public static fields accessible in '" + clazz + "'");
fields.put(clazz, ffields);
}
@Override
public void remove(final Class<?> clazz) {
Assert.notNull(clazz, "A class that was providing conversion services is required");
fields.remove(clazz);
}
@Override
public Object convertFromText(final String value, final Class<?> requiredType, final String optionContext) {
if (!StringUtils.hasText(value)) {
return null;
}
Map<String, Field> ffields = fields.get(requiredType);
if (ffields == null) {
return null;
}
Field f = ffields.get(value);
if (f == null) {
// Fallback to case insensitive search
for (Field candidate : ffields.values()) {
if (candidate.getName().equalsIgnoreCase(value)) {
f = candidate;
break;
}
}
if (f == null) {
// Still not found, despite a case-insensitive search
return null;
}
}
try {
return f.get(null);
}
catch (Exception ex) {
throw new IllegalStateException("Unable to acquire field '" + value + "' from '" + requiredType.getName()
+ "'", ex);
}
}
@Override
public boolean getAllPossibleValues(final List<Completion> completions, final Class<?> requiredType,
final String existingData, final String optionContext, final MethodTarget target) {
Map<String, Field> ffields = fields.get(requiredType);
if (ffields == null) {
return true;
}
for (String field : ffields.keySet()) {
completions.add(new Completion(field));
}
return true;
}
@Override
public boolean supports(final Class<?> requiredType, final String optionContext) {
return fields.get(requiredType) != null;
}
}