io.horizondb.model.protocol.ErrorPayload.java Source code

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Here is the source code for io.horizondb.model.protocol.ErrorPayload.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.protocol;

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

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;

/**
 * <code>Payload</code> used by the server to communicate an error to the client.
 * 
 * @author Benjamin
 * 
 */
@Immutable
public final class ErrorPayload implements Payload {

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

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

            int code = VarInts.readInt(reader);
            String message = VarInts.readString(reader);

            return new ErrorPayload(code, message);
        }
    };

    /**
     * The error message.
     */
    private final String message;

    /**
     * The error code.
     */
    private final int code;

    /**
     * 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 ErrorPayload(int code, String message) {

        notEmpty(message, "the message parameter must not be empty.");

        this.code = code;
        this.message = message;
    }

    /**
     * Returns the error message.
     * 
     * @return the error message.
     */
    public String getMessage() {
        return this.message;
    }

    /**
     * Returns the error code.
     * 
     * @return the error code.
     */
    public int getCode() {
        return this.code;
    }

    /**
     * Creates a new <code>ErrorPayload</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 ErrorPayload parseFrom(ByteReader reader) throws IOException {

        return getParser().parseFrom(reader);
    }

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

        return PARSER;
    }

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

        return new EqualsBuilder().append(this.code, rhs.code).append(this.message, rhs.message).isEquals();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode() {
        return new HashCodeBuilder(-992334025, -1668721805).append(this.message).append(this.code).toHashCode();
    }

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

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

        return VarInts.computeIntSize(this.code) + VarInts.computeStringSize(this.message);
    }

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

        VarInts.writeInt(writer, this.code);
        VarInts.writeString(writer, this.message);
    }
}