ParameterInfo.java

/*
 * Copyright 2012 Guido Steinacker
 *
 * 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 de.otto.jsonhome.generator;

import java.lang.annotation.Annotation;
import java.util.List;

/**
 * Information about a parameter of a method.
 *
 * @author Guido Steinacker
 * @since 03.10.12
 */
public final class ParameterInfo {
    private final String name;
    private final Class<?> type;
    private final List<Annotation> annotations;

    /**
     * Creates a ParameterInfo.
     *
     * @param name name of the parameter. Must neither be null nor empty.
     * @param type type of the parameter. Must not be null.
     * @param annotations annotations of the parameter. Must not be null.
     */
    public ParameterInfo(final String name, final Class<?> type, final List<Annotation> annotations) {
        this.name = name;
        this.type = type;
        this.annotations = annotations;
    }

    /**
     * Returns the name of the method parameter.
     *
     * @return neither null nor empty.
     */
    public String getName() {
        return name;
    }

    /**
     * Returns the type of the parameter.
     *
     * @return never null.
     */
    public Class<?> getType() {
        return type;
    }

    /**
     * Returns the annotations of the parameter.
     *
     * @return list of annotations, never null.
     */
    public List<Annotation> getAnnotations() {
        return annotations;
    }

    /**
     * Returns true if the parameter is annotated with the specified annotationType, false otherwise.
     *
     * @param annotationType the checked type of annotation.
     * @return boolean
     */
    public boolean hasAnnotation(final Class<? extends Annotation> annotationType) {
        for (final Annotation annotation : annotations) {
            if (annotationType.isAssignableFrom(annotation.annotationType())) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns the specified annotation or null, if the parameter is not annotated with the annotationType.
     *
     * @param annotationType the type of the expected annotation.
     * @param <T> the type of the expected annotation.
     * @return Annotation or null.
     */
    public <T extends Annotation> T getAnnotation(final Class<T> annotationType) {
        for (final Annotation annotation : annotations) {
            if (annotationType.isAssignableFrom(annotation.annotationType())) {
                return annotationType.cast(annotation);
            }
        }
        return null;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ParameterInfo that = (ParameterInfo) o;

        if (annotations != null ? !annotations.equals(that.annotations) : that.annotations != null) return false;
        if (name != null ? !name.equals(that.name) : that.name != null) return false;
        if (type != null ? !type.equals(that.type) : that.type != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = name != null ? name.hashCode() : 0;
        result = 31 * result + (type != null ? type.hashCode() : 0);
        result = 31 * result + (annotations != null ? annotations.hashCode() : 0);
        return result;
    }

    @Override
    public String toString() {
        return "ParameterInfo{" +
                "name='" + name + '\'' +
                ", type=" + type +
                ", annotations=" + annotations +
                '}';
    }
}