CheckedSet.java

package org.inferred.freebuilder.processor.excerpt;

import static org.inferred.freebuilder.processor.util.StaticExcerpt.Type.TYPE;
import static org.inferred.freebuilder.processor.util.feature.FunctionPackage.FUNCTION_PACKAGE;

import com.google.common.collect.ImmutableSet;

import org.inferred.freebuilder.processor.util.ParameterizedType;
import org.inferred.freebuilder.processor.util.SourceBuilder;
import org.inferred.freebuilder.processor.util.StaticExcerpt;

import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Set;

/**
 * Excerpts defining a set implementation that delegates to a provided add method to perform
 * element validation and insertion into a backing set.
 */
public class CheckedSet {

  public static Set<StaticExcerpt> excerpts() {
    return ImmutableSet.of(CHECKED_SET);
  }

  private static final StaticExcerpt CHECKED_SET = new StaticExcerpt(TYPE, "CheckedSet") {
    @Override
    public void addTo(SourceBuilder code) {
      ParameterizedType consumer = code.feature(FUNCTION_PACKAGE).consumer().orNull();
      if (consumer != null) {
        code.addLine("")
            .addLine("/**")
            .addLine(" * A set implementation that delegates to a provided add method")
            .addLine(" * to perform element validation and insertion into a backing set.")
            .addLine(" */")
            .addLine("private static class CheckedSet<E> extends %s<E> {", AbstractSet.class)
            .addLine("")
            .addLine("  private final %s<E> set;", Set.class)
            .addLine("  private final %s<E> add;", consumer.getQualifiedName())
            .addLine("")
            .addLine("  CheckedSet(%s<E> set, %s<E> add) {", Set.class, consumer.getQualifiedName())
            .addLine("    this.set = set;")
            .addLine("    this.add = add;")
            .addLine("  }")
            .addLine("")
            .addLine("")
            .addLine("  @Override public %s<E> iterator() {", Iterator.class)
            .addLine("    return set.iterator();")
            .addLine("  }")
            .addLine("")
            .addLine("  @Override public int size() {")
            .addLine("    return set.size();")
            .addLine("  }")
            .addLine("")
            .addLine("  @Override public boolean contains(Object e) {")
            .addLine("    return set.contains(e);")
            .addLine("  }")
            .addLine("")
            .addLine("  @Override public boolean add(E e) {")
            .addLine("    if (!set.contains(e)) {")
            .addLine("      add.accept(e);")
            .addLine("      return true;")
            .addLine("    } else {")
            .addLine("      return false;")
            .addLine("    }")
            .addLine("  }")
            .addLine("")
            .addLine("  @Override public boolean remove(Object e) {")
            .addLine("    return set.remove(e);")
            .addLine("  }")
            .addLine("}");
      }
    }
  };

  private CheckedSet() {}

}