IndexDataType.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.stanbol.entityhub.yard.solr.model;

import org.apache.stanbol.entityhub.servicesapi.defaults.NamespaceEnum;

/**
 * This class is used to define index types. It is only used to provide an unique ID and an human readable
 * name for such types.
 * <p>
 * This type is necessary, because we assume that indices only support string values. Therefore any java type
 * needs to be converted to its string representation. This type is used to preserve the type information.
 * <p>
 * How types are encoded within the index depends on the actual full text index used. The functionality of
 * mapping of this index data types to the actual types as supported by the index is provided by the used
 * {@link FieldMapper} implementation.
 * <p>
 * It is suggested to use the XSD Datatypes as id's for instances where suitable. see <a
 * herf=http://www.w3.org/TR/xmlschema-2/#built-in-datatypes> XSD built in datatypes</a> for more information.
 * 
 * @author Rupert Westenthaler
 * 
 */
public final class IndexDataType {
    /**
     * The default index type is defined as xsd:string (http://www.w3.org/2001/XMLSchema/string)
     */
    public static final IndexDataType DEFAULT = new IndexDataType(NamespaceEnum.xsd + "string");
    /**
     * Prefix used by this type
     */
    private final String id;
    /**
     * Suffix used by this type
     */
    private final String name;

    public IndexDataType(String id) {
        this(id, null);
    }

    /**
     * Creates a new index data type, by defining it's id and name. The id MUST NOT be <code>null</code> nor
     * empty. If the name is <code>null</code>, than the name is generated based on the id by searching the
     * last index of '#', '/' or ':'.
     * 
     * @param id
     *            the unique id used for this data type. Values MUST NOT be <code>null</code> nor empty.
     * @param name
     *            the name for this data type.
     * 
     */
    public IndexDataType(String id, String name) {
        this.id = id;
        if (name == null) {
            String defaultName;
            if (id.lastIndexOf('#') >= 0) {
                defaultName = id.substring(id.lastIndexOf('#') + 1);
            } else if (id.lastIndexOf('/') >= 0) {
                defaultName = id.substring(id.lastIndexOf('/') + 1);
            } else if (id.lastIndexOf(':') >= 0) {
                defaultName = id.substring(id.lastIndexOf(':') + 1);
            } else {
                defaultName = id;
            }
            // convert first char to lower case
            this.name = defaultName.substring(0, 1).toLowerCase() + defaultName.substring(1);
        } else {
            this.name = name;
        }
    }

    /**
     * Getter for the prefix
     * 
     * @return the prefix used by this type or <code>null</code> if this type does not use a prefix.
     */
    public final String getId() {
        return id;
    }

    /**
     * Getter for the name
     * 
     * @return the name of this dataType
     */
    public final String getName() {
        return name;
    }

    @Override
    public int hashCode() {
        return id.hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        return obj instanceof IndexDataType && ((IndexDataType) obj).id.equals(id);
    }

    /**
     * Returns the id of the dataType. Use {@link #getName()} if you need a short variant
     * 
     * @return the id of the dataType
     */
    @Override
    public String toString() {
        return name;
    }
}