Range.java

/*
 * Copyright 2015 JAXIO http://www.jaxio.com
 *
 * 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 com.jaxio.jpa.querybyexample;

import javax.persistence.metamodel.Attribute;
import java.io.Serializable;
import java.util.List;

/**
 * Range support for {@link Comparable} types.
 */
@SuppressWarnings("rawtypes")
public class Range<E, D extends Comparable> implements Serializable {

    /*
     * Range builder
     */
    public static <E, D extends Comparable> Range<E, D> newRange(Attribute<?, ?>... fields) {
        return new Range<E, D>(fields);
    }

    private static final long serialVersionUID = 1L;

    private final PathHolder pathHolder;
    private D from;
    private D to;
    private Boolean includeNull;

    /**
     * Constructs a new Range with no boundaries and no restrictions on field's nullability.
     *
     * @param attributes the path to the attribute of an existing entity.
     */
    public Range(Attribute<?, ?>... attributes) {
        pathHolder = new PathHolder(attributes);
    }

    /**
     * Constructs a new Range.
     *
     * @param from       the lower boundary of this range. Null means no lower boundary.
     * @param to         the upper boundary of this range. Null means no upper boundary.
     * @param attributes the path to the attribute of an existing entity.
     */
    public Range(D from, D to, Attribute<?, ?>... attributes) {
        this(attributes);
        this.from = from;
        this.to = to;
    }

    /**
     * Constructs a new Range.
     *
     * @param from        the lower boundary of this range. Null means no lower boundary.
     * @param to          the upper boundary of this range. Null means no upper boundary.
     * @param includeNull tells whether null should be filtered out or not.
     * @param attributes  the path to the attribute of an existing entity.
     */
    public Range(D from, D to, Boolean includeNull, Attribute<?, ?>... attributes) {
        this(from, to, attributes);
        this.includeNull = includeNull;
    }

    /*
     * Constructs a new Range by copy.
     */
    public Range(Range<E, D> other) {
        this.pathHolder = other.pathHolder;
        this.from = other.from;
        this.to = other.to;
        this.includeNull = other.includeNull;
    }

    /**
     * @return the entity's attribute this Range refers to.
     */
    public List<Attribute<?, ?>> getAttributes() {
        return pathHolder.getAttributes();
    }

    /**
     * @return the lower range boundary or null for unbound lower range.
     */
    public D getFrom() {
        return from;
    }

    /*
     * Sets the lower range boundary. Accepts null for unbound lower range.
     */
    public void setFrom(D from) {
        this.from = from;
    }

    public Range<E, D> from(D from) {
        setFrom(from);
        return this;
    }

    public boolean isFromSet() {
        return getFrom() != null;
    }

    /**
     * @return the upper range boundary or null for unbound upper range.
     */
    public D getTo() {
        return to;
    }

    public Range<E, D> to(D to) {
        setTo(to);
        return this;
    }

    /*
     * Sets the upper range boundary. Accepts null for unbound upper range.
     */
    public void setTo(D to) {
        this.to = to;
    }

    public boolean isToSet() {
        return getTo() != null;
    }

    public void setIncludeNull(Boolean includeNull) {
        this.includeNull = includeNull;
    }

    public Range<E, D> includeNull(Boolean includeNull) {
        setIncludeNull(includeNull);
        return this;
    }

    public Boolean getIncludeNull() {
        return includeNull;
    }

    public boolean isIncludeNullSet() {
        return includeNull != null;
    }

    public boolean isBetween() {
        return isFromSet() && isToSet();
    }

    public boolean isSet() {
        return isFromSet() || isToSet() || isIncludeNullSet();
    }

    @SuppressWarnings("unchecked")
    public boolean isValid() {
        if (isBetween()) {
            return getFrom().compareTo(getTo()) <= 0;
        }
        return true;
    }

    public void resetRange() {
        from = null;
        to = null;
        includeNull = null;
    }
}