StringOptionFieldAdapter.java

/**
 * Copyright 2011-2017 Asakusa Framework Team.
 *
 * 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 com.asakusafw.runtime.io.text.value;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.StandardCharsets;
import java.text.MessageFormat;

import org.apache.hadoop.io.Text;

import com.asakusafw.runtime.io.text.TextUtil;
import com.asakusafw.runtime.io.text.driver.FieldAdapter;
import com.asakusafw.runtime.value.StringOption;

/**
 * An implementation of {@link FieldAdapter} which accepts {@link StringOption}.
 * @since 0.9.1
 */
public final class StringOptionFieldAdapter extends ValueOptionFieldAdapter<StringOption> {

    private final CharsetEncoder encoder = StandardCharsets.UTF_8.newEncoder();

    private final ByteBuffer encodeBuffer = ByteBuffer.allocate(256);

    StringOptionFieldAdapter(String nullFormat) {
        super(nullFormat);
    }

    /**
     * Returns a new builder.
     * @return the created builder
     */
    public static Builder builder() {
        return new Builder();
    }

    @Override
    protected void doParse(CharSequence contents, StringOption property) {
        property.reset();
        Text text = property.get();
        CharBuffer cbuf = CharBuffer.wrap(contents);
        ByteBuffer bbuf = encodeBuffer;
        CharsetEncoder enc = encoder;
        enc.reset();
        while (cbuf.hasRemaining()) {
            bbuf.clear();
            CoderResult result = enc.encode(cbuf, bbuf, true);
            if (result.isError()) {
                throw new IllegalArgumentException(MessageFormat.format(
                        "cannot map input string to UTF-8: {0}",
                        TextUtil.quote(contents)));
            }
            bbuf.flip();
            if (bbuf.hasRemaining()) {
                text.append(bbuf.array(), bbuf.arrayOffset() + bbuf.position(), bbuf.remaining());
            }
            bbuf.clear();
            enc.flush(bbuf);
            bbuf.flip();
            if (bbuf.hasRemaining()) {
                text.append(bbuf.array(), bbuf.arrayOffset() + bbuf.position(), bbuf.remaining());
            }
        }
    }

    @Override
    protected void doEmit(StringOption property, StringBuilder output) {
        property.appendTo(output);
    }

    /**
     * A builder of {@link StringOptionFieldAdapter}.
     * @since 0.9.1
     */
    public static class Builder extends BuilderBase<Builder, StringOptionFieldAdapter> {
        @Override
        public StringOptionFieldAdapter build() {
            return new StringOptionFieldAdapter(getNullFormat());
        }
    }
}