ConstantUsageCheck.java
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package com.qulice.checkstyle;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
/**
* Checks that constant, declared as private field of class is used more than
* once.
*
* @since 0.3
*/
public final class ConstantUsageCheck extends AbstractCheck {
@Override
public int[] getDefaultTokens() {
return new int[]{
TokenTypes.VARIABLE_DEF,
};
}
@Override
public int[] getAcceptableTokens() {
return this.getDefaultTokens();
}
@Override
public int[] getRequiredTokens() {
return this.getDefaultTokens();
}
// @checkstyle NestedIfDepth (35 lines)
@Override
public void visitToken(final DetailAST ast) {
if (ConstantUsageCheck.isField(ast)
&& ConstantUsageCheck.isFinal(ast)) {
final DetailAST namenode = ast.findFirstToken(TokenTypes.IDENT);
if (!"serialVersionUID".equals(this.getText(namenode))) {
this.checkField(ast, namenode);
}
}
}
/**
* Check that constant, declared as private field of class
* is used more than ones.
* @param ast Node which contains VARIABLE_DEF
* @param namenode Node which contains variable name
*/
private void checkField(final DetailAST ast, final DetailAST namenode) {
final String name = namenode.getText();
final int line = namenode.getLineNo();
DetailAST variable = ast.getNextSibling();
int counter = 0;
while (null != variable) {
switch (variable.getType()) {
case TokenTypes.VARIABLE_DEF:
counter += this.parseVarDef(variable, name);
break;
case TokenTypes.CLASS_DEF:
counter += this.parseDef(
variable, name, TokenTypes.OBJBLOCK
);
break;
default:
counter += this.parseDef(variable, name, TokenTypes.SLIST);
break;
}
variable = variable.getNextSibling();
}
if (counter == 0 && ConstantUsageCheck.isPrivate(ast)) {
this.log(
line,
String.format("Private constant \"%s\" is not used", name)
);
}
}
/**
* Parses the variable definition and increments the counter
* if name is found.
* @param variable DetailAST of variable definition
* @param name Name of constant we search for
* @return Zero if not found, 1 otherwise
*/
private int parseVarDef(final DetailAST variable, final String name) {
int counter = 0;
final DetailAST assign =
variable.findFirstToken(TokenTypes.ASSIGN);
if (assign != null) {
DetailAST expression =
assign.findFirstToken(TokenTypes.EXPR);
if (expression == null) {
expression = assign.findFirstToken(
TokenTypes.ARRAY_INIT
);
}
final String text = this.getText(expression);
if (text.contains(name)) {
++counter;
}
}
return counter;
}
/**
* Returns text representation of the specified node, including it's
* children.
* @param node Node, containing text.
* @return Text representation of the node.
*/
private String getText(final DetailAST node) {
final String ret;
if (node == null) {
ret = "";
} else if (0 == node.getChildCount()) {
ret = node.getText();
} else {
final StringBuilder result = new StringBuilder();
DetailAST child = node.getFirstChild();
while (null != child) {
final String text = this.getText(child);
result.append(text);
if (".".equals(node.getText())
&& child.getNextSibling() != null) {
result.append(node.getText());
}
child = child.getNextSibling();
}
ret = result.toString();
}
return ret;
}
/**
* Returns <code>true</code> if specified node has parent node of type
* <code>OBJBLOCK</code>.
* @param node Node to check.
* @return True if parent node is <code>OBJBLOCK</code>, else
* returns <code>false</code>.
*/
private static boolean isField(final DetailAST node) {
final DetailAST parent = node.getParent();
return TokenTypes.OBJBLOCK == parent.getType();
}
/**
* Returns true if specified node has modifiers of type <code>FINAL</code>.
* @param node Node to check.
* @return True if specified node contains modifiers of type
* <code>FINAL</code>, else returns <code>false</code>.
*/
private static boolean isFinal(final DetailAST node) {
final DetailAST modifiers = node.findFirstToken(TokenTypes.MODIFIERS);
return modifiers.getChildCount(TokenTypes.FINAL) > 0;
}
/**
* Returns true if specified node has modifiers of type
* <code>PRIVATE</code>.
* @param node Node to check.
* @return True if specified node contains modifiers of type
* <code>PRIVATE</code>, else returns <code>false</code>.
*/
private static boolean isPrivate(final DetailAST node) {
final DetailAST modifiers = node.findFirstToken(TokenTypes.MODIFIERS);
return modifiers.getChildCount(TokenTypes.LITERAL_PRIVATE) > 0;
}
/**
* Parses the body of the definition (either method or inner class) and
* increments counter each time when it founds constant name.
* @param definition Tree node, containing definition.
* @param name Constant name to search.
* @param type Type of definition start.
* @return Number of found constant usages.
*/
private int parseDef(final DetailAST definition, final String name,
final int type) {
int counter = 0;
final DetailAST modifiers =
definition.findFirstToken(TokenTypes.MODIFIERS);
if (modifiers != null) {
counter += this.parseAnnotation(modifiers, name);
}
final DetailAST opening = definition.findFirstToken(type);
if (null != opening) {
final DetailAST closing = opening.findFirstToken(TokenTypes.RCURLY);
final int start = opening.getLineNo();
final int end = closing.getLineNo() - 1;
final String[] lines = this.getLines();
for (int pos = start; pos < end; pos += 1) {
if (lines[pos].contains(name)) {
counter += 1;
}
}
}
return counter;
}
/**
* Parses the annotation value pair and increments the counter
* if name is found.
* @param modifiers DetailAST of variable definition
* @param name Name of constant we search for
* @return Zero if not found, 1 otherwise
*/
private int parseAnnotation(final DetailAST modifiers, final String name) {
int counter = 0;
final DetailAST variable =
modifiers.findFirstToken(TokenTypes.ANNOTATION);
if (variable != null) {
final String txt = this.getText(variable);
if (txt.contains(name)) {
++counter;
}
}
return counter;
}
}