io.horizondb.model.schema.FieldDefinition.java Source code

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Here is the source code for io.horizondb.model.schema.FieldDefinition.java

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/**
 * Copyright 2013 Benjamin Lerer
 * 
 * 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.horizondb.model.schema;

import io.horizondb.io.ByteReader;
import io.horizondb.io.ByteWriter;
import io.horizondb.io.encoding.VarInts;
import io.horizondb.io.serialization.Parser;
import io.horizondb.io.serialization.Serializable;

import java.io.IOException;

import javax.annotation.concurrent.Immutable;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;

import static org.apache.commons.lang.Validate.notEmpty;
import static org.apache.commons.lang.Validate.notNull;

/**
 * The definition of a field in a record.
 * 
 * @author Benjamin
 */
@Immutable
public final class FieldDefinition implements Serializable {

    /**
     * The parser instance.
     */
    private static final Parser<FieldDefinition> PARSER = new Parser<FieldDefinition>() {

        /**
         * {@inheritDoc}
         */
        @Override
        public FieldDefinition parseFrom(ByteReader reader) throws IOException {

            return new FieldDefinition(VarInts.readString(reader), FieldType.parseFrom(reader));
        }
    };

    /**
     * The name of the field.
     */
    private final String name;

    /**
     * The type of the field.
     */
    private final FieldType type;

    /**
     * Creates a new <code>FieldDefinition</code> instance with the specified name and type.
     * 
     * @param name the field name
     * @param type the field type
     * @return a new <code>FieldDefinition</code> instance.
     */
    public static FieldDefinition newInstance(String name, FieldType type) {

        return new FieldDefinition(name, type);
    }

    /**
     * Creates a new <code>FieldDefinition</code> by reading the data from the specified reader.
     * 
     * @param reader the reader to read from.
     * @throws IOException if an I/O problem occurs
     */
    public static FieldDefinition parseFrom(ByteReader reader) throws IOException {

        return getParser().parseFrom(reader);
    }

    /**
     * Returns the parser that can be used to deserialize <code>FieldDefinition</code> instances.
     * 
     * @return the parser that can be used to deserialize <code>FieldDefinition</code> instances.
     */
    public static Parser<FieldDefinition> getParser() {

        return PARSER;
    }

    /**
     * Returns the field name.
     * 
     * @return the field name.
     */
    public String getName() {
        return this.name;
    }

    /**
     * Returns the type of this field.
     * 
     * @return the type of this field.
     */
    public FieldType getType() {
        return this.type;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals(Object object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof FieldDefinition)) {
            return false;
        }
        FieldDefinition rhs = (FieldDefinition) object;

        return new EqualsBuilder().append(this.name, rhs.name).append(this.type, rhs.type).isEquals();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode() {

        return new HashCodeBuilder(-424505767, -612153919).append(this.name).append(this.type).toHashCode();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE).append("name", this.name)
                .append("type", this.type).toString();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int computeSerializedSize() {

        return VarInts.computeStringSize(this.name) + this.type.computeSerializedSize();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void writeTo(ByteWriter writer) throws IOException {

        VarInts.writeString(writer, this.name);
        this.type.writeTo(writer);
    }

    /**
     * Returns the HQL corresponding to this <code>FieldDefinition</code>.
     * 
     * @return the HQL corresponding to this <code>FieldDefinition</code>.
     */
    public String toHql() {
        return new StringBuilder().append(this.name).append(' ').append(this.type).toString();
    }

    /**
     * Creates a new <code>FieldDefinition</code>.
     * 
     * @param name the field name.
     * @param type the field type.
     */
    private FieldDefinition(String name, FieldType type) {

        notEmpty(name, "the name parameter must not be empty.");
        notNull(type, "the type parameter must not be null.");

        this.name = name;
        this.type = type;
    }
}