InvocableMemberBodyBuilder.java

package org.springframework.roo.classpath.itd;

import org.apache.commons.lang3.Validate;
import org.springframework.roo.classpath.details.InvocableMemberMetadata;

import java.util.Arrays;

/**
 * A simple way of producing method bodies for
 * {@link InvocableMemberMetadata#getBody()}.
 * <p>
 * Method bodies immediately assume they are indented two levels.
 *
 * @author Ben Alex
 * @since 1.0
 */
public class InvocableMemberBodyBuilder {

  public static InvocableMemberBodyBuilder getInstance() {
    return new InvocableMemberBodyBuilder();
  }

  private int indentLevel;
  private boolean reset;
  private final StringBuilder stringBuilder = new StringBuilder();

  /**
   * Constructor for an empty body
   */
  public InvocableMemberBodyBuilder() {
    indentLevel++;
    indentLevel++;
  }

  /**
   * Prints the message, WITHOUT ANY INDENTATION.
   */
  public InvocableMemberBodyBuilder append(final String message) {
    if (message != null && !"".equals(message)) {
      stringBuilder.append(message);
    }
    return this;
  }

  /**
   * Prints the message, WITHOUT ANY INDENTATION.
   */
  public InvocableMemberBodyBuilder append(final String message, final Object... values) {
    if (message != null && !"".equals(message)) {
      stringBuilder.append(String.format(message, values));
    }
    return this;
  }

  /**
   * Prints the message, after adding indents and returns to a new line. This
   * is the most commonly used method.
   */
  public InvocableMemberBodyBuilder appendFormalLine(final String message) {
    appendIndent();
    if (message != null && !"".equals(message)) {
      stringBuilder.append(message);
    }
    return newLine(false);
  }

  /**
   * Prints the message formatted with values, after adding indents and returns to a new line. This
   * is the most commonly used method.
   *
   * @see String#format(String, Object...)
   */
  public InvocableMemberBodyBuilder appendFormalLine(final String message, final Object... values) {
    appendIndent();
    if (message != null && !"".equals(message)) {
      stringBuilder.append(String.format(message, values));
    }
    return newLine(false);
  }

  /**
   * Prints the relevant number of indents.
   */
  public InvocableMemberBodyBuilder appendIndent() {
    for (int i = 0; i < indentLevel; i++) {
      stringBuilder.append("    ");
    }
    return this;
  }

  public String getOutput() {
    if (reset) {
      Validate.isTrue(indentLevel == 0,
          "Indent level must be 0 (not %d) to terminate following a reset", indentLevel);
    } else {
      Validate.isTrue(indentLevel == 2,
          "Indent level must be 2 (not %d) to terminate (use reset to indent to level 0)",
          indentLevel);
    }
    return stringBuilder.toString();
  }

  /**
   * Increases the indent by one level.
   */
  public InvocableMemberBodyBuilder indent() {
    indentLevel++;
    return this;
  }

  /**
   * Decreases the indent by one level.
   */
  public InvocableMemberBodyBuilder indentRemove() {
    indentLevel--;
    return this;
  }

  public InvocableMemberBodyBuilder newLine() {
    newLine(true);
    return this;
  }

  /**
   * Prints a blank line, ensuring any indent is included before doing so.
   */
  public InvocableMemberBodyBuilder newLine(final boolean indentBefore) {
    if (indentBefore) {
      appendIndent();
    }
    // We use \n for consistency with JavaParser's DumpVisitor, which always
    // uses \n
    stringBuilder.append("\n");
    return this;
  }

  /**
   * Resets the indent to zero.
   */
  public InvocableMemberBodyBuilder reset() {
    indentLevel = 0;
    reset = true;
    return this;
  }
}