uk.gov.gchq.gaffer.function.ConsumerFunction.java Source code

Introduction

Here is the source code for uk.gov.gchq.gaffer.function.ConsumerFunction.java

Source

/*
 * Copyright 2016 Crown Copyright
 *
 * 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 uk.gov.gchq.gaffer.function;

import com.fasterxml.jackson.annotation.JsonIgnore;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
import uk.gov.gchq.gaffer.function.annotation.Inputs;
import java.lang.annotation.AnnotationFormatError;
import java.util.Arrays;

/**
 * A <code>ConsumerFunction</code> is a {@link uk.gov.gchq.gaffer.function.Function} that consumes input records. Implementations
 * should be annotated with the {@link uk.gov.gchq.gaffer.function.annotation.Inputs} annotation specifying the input record
 * structure that the function accepts.
 */
public abstract class ConsumerFunction implements Function {
    protected Class<?>[] inputs;

    @Override
    public abstract ConsumerFunction statelessClone();

    /**
     * @return Input record structure accepted by this <code>ConsumerFunction</code>.
     */
    @JsonIgnore
    public Class<?>[] getInputClasses() {
        if (null == inputs) {
            processInputAnnotation();
        }

        return Arrays.copyOf(inputs, inputs.length);
    }

    /**
     * Retrieves the input record structure from the {@link uk.gov.gchq.gaffer.function.annotation.Inputs} annotation.
     */
    private void processInputAnnotation() {
        final Inputs annotation = getClass().getAnnotation(Inputs.class);
        if (null == annotation) {
            throw new AnnotationFormatError(
                    "All consumer function classes must have inputs defined using the 'Inputs' annotation on the class."
                            + " Class: " + getClass());
        }

        inputs = annotation.value();
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }

        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        final ConsumerFunction that = (ConsumerFunction) o;

        return new EqualsBuilder().append(inputs, that.inputs).isEquals();
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder(17, 37).append(inputs).toHashCode();
    }

    @Override
    public String toString() {
        return new ToStringBuilder(this).append("inputs", inputs).toString();
    }
}