Path.java

package jpasearch.repository.query;

import java.io.Serializable;

import javax.persistence.metamodel.PluralAttribute;
import javax.persistence.metamodel.SingularAttribute;

import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;

/**
 * Holder class for path used by the {@link OrderBy},
 * {@link jpasearch.repository.query.selector.PropertySelector},
 * {@link jpasearch.repository.query.selector.TermSelector} and
 * {@link SearchParameters}.
 */
public class Path<FROM, TO> implements Serializable {
    private static final long serialVersionUID = 201403271745L;

    private final String path;
    private final Class<? super FROM> from;

    public Path(SingularAttribute<? super FROM, TO> attribute) {
        this(attribute.getDeclaringType().getJavaType(), attribute.getName());
    }

    public Path(PluralAttribute<? super FROM, ?, TO> attribute) {
        this(attribute.getDeclaringType().getJavaType(), attribute.getName());
    }

    private <T> Path(Path<FROM, T> old, SingularAttribute<? super T, TO> attribute) {
        this(old.from, old.path + "." + attribute.getName());
    }

    private <T> Path(Path<FROM, T> old, PluralAttribute<? super T, ?, TO> attribute) {
        this(old.from, old.path + "." + attribute.getName());
    }

    public Path(Class<? super FROM> from, String path) {
        this.from = from;
        this.path = path;
    }

    public <T> Path<FROM, T> add(SingularAttribute<? super TO, T> attribute) {
        return new Path<FROM, T>(this, attribute);
    }

    public <T> Path<FROM, T> add(PluralAttribute<? super TO, ?, T> attribute) {
        return new Path<FROM, T>(this, attribute);
    }

    public String getPath() {
        return path;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = (prime * result) + ((from == null) ? 0 : from.hashCode());
        result = (prime * result) + ((path == null) ? 0 : path.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        if (obj.getClass() != getClass()) {
            return false;
        }
        Path<?, ?> rhs = (Path<?, ?>) obj;
        return new EqualsBuilder().append(path, rhs.path).append(from, rhs.from).isEquals();
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE);
    }

}