METValidator.java

package codetail.text.validation;

import android.support.annotation.NonNull;

/**
 * Base Validator class to either implement or inherit from for custom validation
 */
public abstract class METValidator {

    /**
     * Error message that the view will display if validation fails.
     * <p/>
     * This is protected, so you can change this dynamically in your {@link #isValid(CharSequence, boolean)}
     * implementation. If necessary, you can also interact with this via its getter and setter.
     */
    protected String errorMessage;

    public METValidator(@NonNull String errorMessage) {
        this.errorMessage = errorMessage;
    }

    @NonNull
    public String getErrorMessage() {
        return this.errorMessage;
    }

    public void setErrorMessage(@NonNull String errorMessage) {
        this.errorMessage = errorMessage;
    }

    /**
     * Abstract method to implement your own validation checking.
     *
     * @param text    The CharSequence representation of the text in the EditText field. Cannot be null, but may be empty.
     * @param isEmpty Boolean indicating whether or not the text param is empty
     * @return True if valid, false if not
     */
    public abstract boolean isValid(@NonNull CharSequence text, boolean isEmpty);

}