UnnecessaryLocalRule.java
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package com.qulice.pmd.rules;
import java.util.List;
import java.util.Map;
import net.sourceforge.pmd.lang.java.ast.ASTArgumentList;
import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
import net.sourceforge.pmd.lang.java.ast.ASTReturnStatement;
import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclarator;
import net.sourceforge.pmd.lang.java.ast.JavaNode;
import net.sourceforge.pmd.lang.java.rule.AbstractJavaRule;
import net.sourceforge.pmd.lang.symboltable.NameDeclaration;
import net.sourceforge.pmd.lang.symboltable.NameOccurrence;
/**
* Rule to check unnecessary local variables.
*
* @since 0.4
*/
public final class UnnecessaryLocalRule extends AbstractJavaRule {
@Override
public Object visit(final ASTMethodDeclaration meth, final Object data) {
Object ndata = data;
if (!meth.isAbstract() && !meth.isNative()) {
ndata = super.visit(meth, data);
}
return ndata;
}
@Override
public Object visit(final ASTReturnStatement rtn, final Object data) {
final ASTVariableDeclarator name =
rtn.getFirstChildOfType(ASTVariableDeclarator.class);
if (name != null) {
this.usages(rtn, data, name);
}
return data;
}
@Override
public Object visit(final ASTArgumentList rtn, final Object data) {
final List<ASTVariableDeclarator> names =
rtn.findChildrenOfType(ASTVariableDeclarator.class);
for (final ASTVariableDeclarator name : names) {
this.usages(rtn, data, name);
}
return data;
}
/**
* Report when number of variable usages is equal to zero.
* @param node Node to check.
* @param data Context.
* @param name Variable name.
*/
@SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
private void usages(final JavaNode node, final Object data,
final ASTVariableDeclarator name) {
final Map<NameDeclaration, List<NameOccurrence>> vars = name
.getScope().getDeclarations();
// @checkstyle LineLength (1 line)
for (final Map.Entry<NameDeclaration, List<NameOccurrence>> entry
: vars.entrySet()) {
final List<NameOccurrence> usages = entry.getValue();
if (usages.size() > 1) {
continue;
}
for (final NameOccurrence occ: usages) {
if (occ.getLocation().equals(name)) {
this.addViolation(
data, node, new Object[]{name.getImage()}
);
}
}
}
}
}