src/android/src/com/google/android/inputmethod/japanese/ui/CandidateLayout.java

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package org.mozc.android.inputmethod.japanese.ui;

import org.mozc.android.inputmethod.japanese.protobuf.ProtoCandidates.CandidateWord;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;

import android.text.Layout;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Represents the layout information calculated by a layouter.
 *
 */
public class CandidateLayout {

  /** Horizontal span which is occupied by a CandidateWord. */
  public static class Span {
    private final Optional<CandidateWord> candidateWord;
    private float left;
    private float right;

    private final float valueWidth;
    private final float descriptionWidth;
    private final List<String> splitDescriptionList;

    /**
     * This is a cache to improve the rendering performance.
     * In theory, it's better to have another structure to keep the cache,
     * but put this here for the simpler implementation.
     */
    private Optional<Layout> cachedLayout = Optional.absent();

    /** @param candidateWord the candidate word of this span. Absent if the span is
     * reserved empty one, which is for folding button. */
    public Span(Optional<CandidateWord> candidateWord,
                float valueWidth, float descriptionWidth,
                List<String> splitDescriptionList) {
      this.candidateWord = Preconditions.checkNotNull(candidateWord);
      this.valueWidth = valueWidth;
      this.descriptionWidth = descriptionWidth;
      this.splitDescriptionList = Preconditions.checkNotNull(splitDescriptionList);
    }

    public Optional<CandidateWord> getCandidateWord() {
      return candidateWord;
    }

    public float getLeft() {
      return left;
    }

    /** @param left the position of the left edge. Must be non negative value. */
    public void setLeft(float left) {
      Preconditions.checkArgument(left >= 0);
      this.left = left;
    }

    public float getRight() {
      return right;
    }

    /** @param right the position of the right edge. Must be equal or greater than left. */
    public void setRight(float right) {
      Preconditions.checkArgument(left <= right);
      this.right = right;
    }

    /** @return the width (== right - left) */
    public float getWidth() {
      return right - left;
    }

    public float getValueWidth() {
      return valueWidth;
    }

    public float getDescriptionWidth() {
      return descriptionWidth;
    }

    public List<String> getSplitDescriptionList() {
      return splitDescriptionList;
    }

    public Optional<Layout> getCachedLayout() {
      return cachedLayout;
    }

    public void setCachedLayout(Layout cachedLayout) {
      this.cachedLayout = Optional.of(Preconditions.checkNotNull(cachedLayout));
    }
  }

  public static class Row {
    /** Heuristic parameter for the number of spans in a row. */
    private static final int TYPICAL_SPANS_PER_ROW = 5;
    private final List<Span> spans = new ArrayList<Span>(TYPICAL_SPANS_PER_ROW);

    private float top;
    private float height;
    private float width;

    public float getTop() {
      return top;
    }

    public void setTop(float top) {
      this.top = top;
    }

    public float getHeight() {
      return height;
    }

    public void setHeight(float height) {
      this.height = height;
    }

    public float getWidth() {
      return width;
    }

    public void setWidth(float width) {
      this.width = width;
    }

    public List<Span> getSpanList() {
      return Collections.unmodifiableList(spans);
    }

    public void addSpan(Span span) {
      spans.add(Preconditions.checkNotNull(span));
    }
  }

  private final List<Row> rowList;
  private final float contentWidth;
  private final float contentHeight;

  public CandidateLayout(List<Row> rowList, float contentWidth, float contentHeight) {
    this.rowList = Preconditions.checkNotNull(rowList);
    this.contentWidth = contentWidth;
    this.contentHeight = contentHeight;
  }

  public List<Row> getRowList() {
    return rowList;
  }

  public float getContentWidth() {
    return contentWidth;
  }

  public float getContentHeight() {
    return contentHeight;
  }
}