// CSE 143, Homework 2: HTML Manager
// Instructor-provided code. You should not modify this file!
// Resource file for HTMLManager. Put this file in the same directory
// as HTMlManager.java, HTMLTag.java, HTMLTagType.java and HTMLMain.java.
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
/** An HTMLTag object represents an HTML tag, such as or . */
public class HTMLTag {
private static final Set SELF_CLOSING_TAGS =
new HashSet(Arrays.asList(
"!DOCTYPE", "area", "base", "basefont", "br",
"col", "command", "embed", "hr", "img", "input",
"keygen", "link", "meta", "param", "wbr", "track", "?xml"));
private final String element;
private final String attributes;
private final String contents;
private final HTMLTagType type;
public static final String INDENT_STRING = " ";
/**
* Constructs an HTML tag with the given element (e.g. "table"), type
* and content as internal content.
* Self-closing tags like
are considered to be "opening" tags,
* and return true from the isOpenTag method.
* Throws a NullPointerException if element is null.
*/
public HTMLTag(String element, HTMLTagType type, String contents) {
if (contents == null) {
contents = "";
}
if (element.startsWith("--")) {
this.element = element;
this.attributes = "";
} else {
int space = element.indexOf(" ");
if (space != -1) {
this.element = element.substring(0, space);
this.attributes = element.substring(space + 1);
} else {
this.element = element;
this.attributes = "";
}
}
if (SELF_CLOSING_TAGS.contains(this.element)) {
this.type = HTMLTagType.SELF_CLOSING;
} else {
this.type = type;
}
if (contents != null) {
contents = contents.replaceAll("\n$", "");
}
this.contents = contents;
}
/**
* Constructs an HTML tag with the given element (e.g. "table") and type.
* Self-closing tags like
are considered to be "opening" tags,
* and return true from the isOpenTag method.
* Throws a NullPointerException if element is null.
*/
public HTMLTag(String element, HTMLTagType type) {
this(element, type, null);
}
/**
* Returns true if this HTML tag is an "opening" (starting) tag.
* Self-closing tags like
are NOT considered to be "opening" tags.
*/
public boolean isOpening() {
return this.type == HTMLTagType.OPENING;
}
/**
* Returns true if this HTML tag is an "closing" (finishing) tag.
* Self-closing tags like
are NOT considered to be "closing" tags.
*/
public boolean isClosing() {
return this.type == HTMLTagType.CLOSING;
}
/**
* Returns true if this tag does not requires a matching closing tag,
* which is the case for certain elements such as br and img.
*/
public boolean isSelfClosing() {
return this.type == HTMLTagType.SELF_CLOSING;
}
/**
* Returns true if this tag is an HTML comment
*/
public boolean isComment() {
return this.element.startsWith("--");
}
/**
* Returns true if the given other tag matches this tag;
* that is, if they have the same element but opposite types,
* such as and .
*
* pre: If other is null, this method will throw a NullPointerException
*/
public boolean matches(HTMLTag other) {
boolean thisOpens = this.type == HTMLTagType.OPENING;
boolean thisCloses = this.type == HTMLTagType.CLOSING;
boolean otherOpens = other.type == HTMLTagType.OPENING;
boolean otherCloses = other.type == HTMLTagType.CLOSING;
return this.element.equalsIgnoreCase(other.element)
&& ((thisOpens && otherCloses) || (thisCloses && otherOpens));
}
/**
* Returns true if the given other tag equals this tag;
* that is, if they have the same element and the same types:
* such as and , or and
*
* pre: If other is null, this method will throw a NullPointerException
*/
public boolean equals(HTMLTag other) {
return this.element.equalsIgnoreCase(other.element)
&& this.type == other.type;
}
/**
* Returns a tag that matches this tag, and has the same element.
*
* pre: If this tag is a self-closing tag, it matches itself
*/
public HTMLTag getMatching() {
if (this.type == HTMLTagType.SELF_CLOSING) {
return new HTMLTag(this.element, HTMLTagType.SELF_CLOSING);
} else if (this.type == HTMLTagType.OPENING) {
return new HTMLTag(this.element, HTMLTagType.CLOSING);
} else if (this.type == HTMLTagType.CLOSING) {
return new HTMLTag(this.element, HTMLTagType.OPENING);
} else {
System.err.println("Invalid Tag Type.");
System.exit(1);
return null;
}
}
/**
* Returns a string representation of this HTML tag, such as "".
*/
public String toString() {
boolean hasAttributes = this.attributes.length() > 0;
String attr = (hasAttributes ? " " + this.attributes : "");
String contents = this.contents == null ? "" : this.contents;
if (this.isComment()) {
return "";
}
else if (this.type == HTMLTagType.OPENING) {
return "<" + this.element + attr + ">" + contents;
}
else if (this.type == HTMLTagType.CLOSING) {
return "" + contents;
}
else if (this.type == HTMLTagType.SELF_CLOSING) {
return "<" + this.element + attr + " />" + contents;
}
else {
System.err.println("Invalid Tag Type.");
System.exit(1);
return null;
}
}
/**
* Returns a String representation of the tag, with the given indent
*/
public String toString(int indent) {
StringBuilder result = new StringBuilder();
for (int j = 0; j < indent; j++) {
result.append(INDENT_STRING);
}
result.append(this);
return result.toString();
}
}