LiteralToObject.java

/*
 * Copyright 2016 Christoph Böhme
 *
 * 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 org.culturegraph.mf.mangling;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.culturegraph.mf.framework.FluxCommand;
import org.culturegraph.mf.framework.ObjectReceiver;
import org.culturegraph.mf.framework.StreamReceiver;
import org.culturegraph.mf.framework.annotations.Description;
import org.culturegraph.mf.framework.annotations.In;
import org.culturegraph.mf.framework.annotations.Out;
import org.culturegraph.mf.framework.helpers.DefaultStreamPipe;

/**
 * Emits the values of literals matching {@literal #setPattern(String)}
 * as objects.
 * <p>
 * The matcher does only match the literal name and does not
 * take the enclosing entities into account.
 *
 * @author Christoph Böhme
 *
 */
@Description("Emits literal values as objects.")
@In(StreamReceiver.class)
@Out(String.class)
@FluxCommand("literal-to-object")
public final class LiteralToObject extends DefaultStreamPipe<ObjectReceiver<String>> {

	/**
	 * Default value for {@link #setPattern(String)}.
	 */
	public static final java.lang.String DEFAULT_PATTERN = ".*";

	private Matcher matcher = Pattern.compile(DEFAULT_PATTERN).matcher("");

	/**
	 * Sets the pattern against which literal names are matched. Only the
	 * values of matching literals are converted into objects.
	 * <p>
	 * The parameter can be changed at any time during processing. It becomes
	 * effective with the next literal being processed.
	 * <p>
	 * The default pattern matches all literal names including empty ones.
	 *
	 * @param pattern a Java regular expression
	 */
	public void setPattern(final String pattern) {
		this.matcher = Pattern.compile(pattern).matcher("");
	}

	public String getPattern() {
		return matcher.pattern().pattern();
	}

	@Override
	public void literal(final String name, final String value) {
		assert !isClosed();
		matcher.reset(name);
		if (matcher.matches()) {
			getReceiver().process(value);
		}
	}

}