Field.java

/* Copyright 2013 The jeo project. All rights reserved.
 *
 * 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 io.jeo.vector;

import java.util.Locale;
import java.util.Map;

import org.osgeo.proj4j.CoordinateReferenceSystem;

import com.vividsolutions.jts.geom.Geometry;

/**
 * Describes an attribute of a {@link Feature}.
 * 
 * @author Justin Deoliveira, OpenGeo
 */
public class Field {

    /** field name */
    String name;

    /** field type */
    Class<?> type;

    /** field crs */
    CoordinateReferenceSystem crs;

    /** additional properties */
    Map<String,Object> props;

    public Field(String name, Class<?> type) {
        this(name, type, null, null);
    }

    public Field(String name, Class<?> type, Map<String,Object> props) {
        this(name, type, null, props);
    }

    public Field(String name, Class<?> type, CoordinateReferenceSystem crs) {
        this.name = name;
        this.type = type != null ? type : Object.class;
        this.crs = crs;
    }

    public Field(String name, Class<?> type, CoordinateReferenceSystem crs, Map<String,Object> props) {
        this.name = name;
        this.type = type != null ? type : Object.class;
        this.crs = crs;
        this.props = props;
    }
    
    /**
     * The name of the field.
     */
    public String name() {
        return name;
    }

    /**
     * The type of the field.
     */
    public Class<?> type() {
        return type;
    }

    /**
     * Determines if the field refers to a geometry type.
     * <p>
     * This method is short-hand for <code>Geometry.class.isAssignableFrom(geteType())</code>.
     * <p>
     * 
     * @return The crs object, or <code>null</code>.
     */
    public boolean geometry() {
        return Geometry.class.isAssignableFrom(type);
    }

    /**
     * Returns the coordinate reference system associated with the field, if set.
     * <p>
     * This value is typically only set when {@link #geometry()} returns <code>true</code>.
     * </p>
     */
    public CoordinateReferenceSystem crs() {
        return crs;
    }

    /**
     * Gets an extended property of the field.
     * <p>
     * Typically extended properties are specific to a particular driver that needs to associate
     * format specific information with a field.
     * </p> 
     * 
     * @param key The property key.
     * 
     * @return The property value or <code>null</code> if no such property is defined.
     */
    public <T> T property(String key, Class<T> clazz) {
        return props != null ? clazz.cast(props.get(key)) : null;
    }

    @Override
    public String toString() {
        return String.format(Locale.ROOT,"(%s,%s)", name, type().getSimpleName());
    }

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

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Field other = (Field) obj;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (type == null) {
            if (other.type != null)
                return false;
        } else if (!type.equals(other.type))
            return false;
        if (crs == null) {
            if (other.crs != null)
                return false;
        } else if (!crs.equals(other.crs))
            return false;
        return true;
    }

    
}